Pianotech

Question about key ratios. I am about to replace the angled capstans on a 95 year old Hamburg Steinway model M grand with straight WNG capstans. I find the straight line drifts 3 mm from the balance hole #1 at 117.5mm to 120.5mm at #88. The balance rail holes are located precisely the same distance from the back of the key at #1 and #88. Key ratio of the naturals from rep center to balance hole is 1:1.89 on #1 and 1:1.94 on #88. Could this be intentional or just a manufacturing error?

Question about key ratios. I am about to replace the angled capstans on a 95 year old Hamburg Steinway model M grand with straight WNG capstans. I find the straight line drifts 3 mm from the balance hole #1 at 117.5mm to 120.5mm at #88. The balance rail holes are located precisely the same distance from the back of the key at #1 and #88. Key ratio of the naturals from rep center to balance hole is 1:1.89 on #1 and 1:1.94 on #88. Could this be intentional or just a manufacturing error?

I wouldn't worry about that.  It does happen fairly often.  I doubt it's by design but rather an execution error that probably relates to strike point determination, stack orientation followed by determining the capstan line last.  That system creates all kinds of problems with NY Steinways though I don't know the exactly procedure that Hamburg uses.  The key ratio being perfectly symmetrical from bass to treble is nice but not crucial and this difference is not huge and won't make that much difference in your final weight and balance. 

The ratio is a bit high though (depending on how you took the measurements) so I would certainly be using 17 mm shanks on this and it may be that the hammer weight will be a consideration even with that.  This can all be determined (if you're following my TW beta testing I'd be happy to run numbers for you).   

Question about key ratios. I am about to replace the angled capstans on a 95 year old Hamburg Steinway model M grand with straight WNG capstans. I find the straight line drifts 3 mm from the balance hole #1 at 117.5mm to 120.5mm at #88. The balance rail holes are located precisely the same distance from the back of the key at #1 and #88. Key ratio of the naturals from rep center to balance hole is 1:1.89 on #1 and 1:1.94 on #88. Could this be intentional or just a manufacturing error?

I wouldn't worry about that.  It does happen fairly often.  I doubt it's by design but rather an execution error that probably relates to strike point determination, stack orientation followed by determining the capstan line last.  That system creates all kinds of problems with NY Steinways though I don't know the exactly procedure that Hamburg uses.  The key ratio being perfectly symmetrical from bass to treble is nice but not crucial and this difference is not huge and won't make that much difference in your final weight and balance. 

The ratio is a bit high though (depending on how you took the measurements) so I would certainly be using 17 mm shanks on this and it may be that the hammer weight will be a consideration even with that.  This can all be determined (if you're following my TW beta testing I'd be happy to run numbers for you).   

Question about key ratios. I am about to replace the angled capstans on a 95 year old Hamburg Steinway model M grand with straight WNG capstans. I find the straight line drifts 3 mm from the balance hole #1 at 117.5mm to 120.5mm at #88. The balance rail holes are located precisely the same distance from the back of the key at #1 and #88. Key ratio of the naturals from rep center to balance hole is 1:1.89 on #1 and 1:1.94 on #88. Could this be intentional or just a manufacturing error?

Wow, 85 grams!!! Yipes

Contact me privately and I'll give you the info and the data I need to run numbers. I have a program I've been using for years that I'm beta testing with some other techs using their projects. It's a simple way to determine leverage/hammer weight compatibility and optimization and will give you  hammer weights, or strike weights, and the key leading to produce a target balance weight. Simple system that gives you the raw data you need to put together the action.

i would definitely turn the capstan to 90 degrees,  even if you used the same whole location, turning it to 90 degrees would lower the action ratio.

if you're familiar with Stanwood weigh off procedures for BW, FW and SW (or hammer weight is ok) that's helpful. 

I wouldn't worry about that.  It does happen fairly often.  I doubt it's by design but rather an execution error that probably relates to strike point determination, stack orientation followed by determining the capstan line last.  That system creates all kinds of problems with NY Steinways though I don't know the exactly procedure that Hamburg uses.  The key ratio being perfectly symmetrical from bass to treble is nice but not crucial and this difference is not huge and won't make that much difference in your final weight and balance. 

The ratio is a bit high though (depending on how you took the measurements) so I would certainly be using 17 mm shanks on this and it may be that the hammer weight will be a consideration even with that.  This can all be determined (if you're following my TW beta testing I'd be happy to run numbers for you).   

Question about key ratios. I am about to replace the angled capstans on a 95 year old Hamburg Steinway model M grand with straight WNG capstans. I find the straight line drifts 3 mm from the balance hole #1 at 117.5mm to 120.5mm at #88. The balance rail holes are located precisely the same distance from the back of the key at #1 and #88. Key ratio of the naturals from rep center to balance hole is 1:1.89 on #1 and 1:1.94 on #88. Could this be intentional or just a manufacturing error?

Key ratio screws up inertia by not being a leverage measurement. Its a ratio. A 12 inch key with a capstan set back 6 inches is the same ratio as a 4 foot key with a capstan set back 2 feet. 

FW screws up inertia because you're going by DW to locate. An easy test to perform to show the flaw of FW  lets say DW is 50 grams you could use up to 200 grams near the balance pin to achieve a 50 gram DW. And pre- conceived FW schemes also do not work. Its only an illusion of balance because DW is smooth. How about the FW difference between sharps and naturals. That's can be an even inertia buster, as well as a couple of others.

When inertia is actually smooth its an incredible experience, because a subconscious micro - finger management of constant correction is gone.

-chris

Wow, 85 grams!!! Yipes

Contact me privately and I'll give you the info and the data I need to run numbers. I have a program I've been using for years that I'm beta testing with some other techs using their projects. It's a simple way to determine leverage/hammer weight compatibility and optimization and will give you  hammer weights, or strike weights, and the key leading to produce a target balance weight. Simple system that gives you the raw data you need to put together the action.

i would definitely turn the capstan to 90 degrees,  even if you used the same whole location, turning it to 90 degrees would lower the action ratio.

if you're familiar with Stanwood weigh off procedures for BW, FW and SW (or hammer weight is ok) that's helpful. 

I wouldn't worry about that.  It does happen fairly often.  I doubt it's by design but rather an execution error that probably relates to strike point determination, stack orientation followed by determining the capstan line last.  That system creates all kinds of problems with NY Steinways though I don't know the exactly procedure that Hamburg uses.  The key ratio being perfectly symmetrical from bass to treble is nice but not crucial and this difference is not huge and won't make that much difference in your final weight and balance. 

The ratio is a bit high though (depending on how you took the measurements) so I would certainly be using 17 mm shanks on this and it may be that the hammer weight will be a consideration even with that.  This can all be determined (if you're following my TW beta testing I'd be happy to run numbers for you).   

Question about key ratios. I am about to replace the angled capstans on a 95 year old Hamburg Steinway model M grand with straight WNG capstans. I find the straight line drifts 3 mm from the balance hole #1 at 117.5mm to 120.5mm at #88. The balance rail holes are located precisely the same distance from the back of the key at #1 and #88. Key ratio of the naturals from rep center to balance hole is 1:1.89 on #1 and 1:1.94 on #88. Could this be intentional or just a manufacturing error?

Key ratio is a component of leverage.  When you calculate the overall leverage as the product of levers the key is one of those levers (hammer shank and hammer and wippen being the other two).  I don't find the key ratio particularly useful except as a sign post (reminds of that old saying "the sign points to Berlin but it doesn't go to Berlin") especially since I don't really use a calculation of AR in my system (or inertia for that matter).  But it tells you something since about the direction of the overall system. With Steinway pianos, and many others, the key ratio is the only real variable.  The hammer/shank lever is predictable with bore distance and knuckle hanging somewhat consistent and the wippen lever doesn't change either, though the capstan position under the wippen cushion can, certainly. 

While you are correct about lead placement skewing the results, try putting 200 grams of lead near the balance rail, good luck.  It's an unachievable hypothetical and something that no one would ever try, hopefully.  It's not a good example.  There's a practical limit to the options we have to install leads.  The lead contributes some to the inertia but less than you think.  The unleaded key contributes too, probably more than you think.  Putting more lead near the balance point (the Steinway "accelerated action") is questionable as a benefit because, as you suggest, it simply adds more mass to the key, though it's not quite that simple.  But the biggest driver of inertia is the overall leverage and the hammer mass.  

Ultimately, since you are looking for a smooth inertia curve (inertia is not uniform through the action either because of decreasing hammer mass) a smooth transition in the leading pattern is desirable. And with that the inertia always decreases as you ascend the scale.   And let's not forget that we don't actually play the keys at the end of the key where we measure things like DW and UW.  Our fingers are moving all over the keys, in and out, and every time that change in position happens the effective leverage changes and with it the inertia.  It's really pretty remarkable that the human brain, in spite of that, still has a perception of evenness, even though the action, as it is played with variable key contact points, is anything but.  

Key ratio screws up inertia by not being a leverage measurement. Its a ratio. A 12 inch key with a capstan set back 6 inches is the same ratio as a 4 foot key with a capstan set back 2 feet. 

FW screws up inertia because you're going by DW to locate. An easy test to perform to show the flaw of FW  lets say DW is 50 grams you could use up to 200 grams near the balance pin to achieve a 50 gram DW. And pre- conceived FW schemes also do not work. Its only an illusion of balance because DW is smooth. How about the FW difference between sharps and naturals. That's can be an even inertia buster, as well as a couple of others.

When inertia is actually smooth its an incredible experience, because a subconscious micro - finger management of constant correction is gone.

-chris

Wow, 85 grams!!! Yipes

Contact me privately and I'll give you the info and the data I need to run numbers. I have a program I've been using for years that I'm beta testing with some other techs using their projects. It's a simple way to determine leverage/hammer weight compatibility and optimization and will give you  hammer weights, or strike weights, and the key leading to produce a target balance weight. Simple system that gives you the raw data you need to put together the action.

i would definitely turn the capstan to 90 degrees,  even if you used the same whole location, turning it to 90 degrees would lower the action ratio.

if you're familiar with Stanwood weigh off procedures for BW, FW and SW (or hammer weight is ok) that's helpful. 

I wouldn't worry about that.  It does happen fairly often.  I doubt it's by design but rather an execution error that probably relates to strike point determination, stack orientation followed by determining the capstan line last.  That system creates all kinds of problems with NY Steinways though I don't know the exactly procedure that Hamburg uses.  The key ratio being perfectly symmetrical from bass to treble is nice but not crucial and this difference is not huge and won't make that much difference in your final weight and balance. 

The ratio is a bit high though (depending on how you took the measurements) so I would certainly be using 17 mm shanks on this and it may be that the hammer weight will be a consideration even with that.  This can all be determined (if you're following my TW beta testing I'd be happy to run numbers for you).   

Question about key ratios. I am about to replace the angled capstans on a 95 year old Hamburg Steinway model M grand with straight WNG capstans. I find the straight line drifts 3 mm from the balance hole #1 at 117.5mm to 120.5mm at #88. The balance rail holes are located precisely the same distance from the back of the key at #1 and #88. Key ratio of the naturals from rep center to balance hole is 1:1.89 on #1 and 1:1.94 on #88. Could this be intentional or just a manufacturing error?

A hub cap is a component of an automobile, but it doesn't tell you how much gas is in the tank.

"200 gram" was an illustration which comes from a video i did several months back. I was showing the range of weight possibilities in a key based on its positioning.

https://www.youtube.com/watch?v=KT1494-cDFM

I also see no practical purpose for stating which mass is more important, or why its dissected like that. Just a weird way of thinking if you ask me. For calculating inertia, all mass and where they are located on the levers are all in the equation.

Thus a direct measurement instead of numerous indirect ones.

Have a good day.

-chris

Key ratio is a component of leverage.  When you calculate the overall leverage as the product of levers the key is one of those levers (hammer shank and hammer and wippen being the other two).  I don't find the key ratio particularly useful except as a sign post (reminds of that old saying "the sign points to Berlin but it doesn't go to Berlin") especially since I don't really use a calculation of AR in my system (or inertia for that matter).  But it tells you something since about the direction of the overall system. With Steinway pianos, and many others, the key ratio is the only real variable.  The hammer/shank lever is predictable with bore distance and knuckle hanging somewhat consistent and the wippen lever doesn't change either, though the capstan position under the wippen cushion can, certainly. 

While you are correct about lead placement skewing the results, try putting 200 grams of lead near the balance rail, good luck.  It's an unachievable hypothetical and something that no one would ever try, hopefully.  It's not a good example.  There's a practical limit to the options we have to install leads.  The lead contributes some to the inertia but less than you think.  The unleaded key contributes too, probably more than you think.  Putting more lead near the balance point (the Steinway "accelerated action") is questionable as a benefit because, as you suggest, it simply adds more mass to the key, though it's not quite that simple.  But the biggest driver of inertia is the overall leverage and the hammer mass.  

Ultimately, since you are looking for a smooth inertia curve (inertia is not uniform through the action either because of decreasing hammer mass) a smooth transition in the leading pattern is desirable. And with that the inertia always decreases as you ascend the scale.   And let's not forget that we don't actually play the keys at the end of the key where we measure things like DW and UW.  Our fingers are moving all over the keys, in and out, and every time that change in position happens the effective leverage changes and with it the inertia.  It's really pretty remarkable that the human brain, in spite of that, still has a perception of evenness, even though the action, as it is played with variable key contact points, is anything but.  

Key ratio screws up inertia by not being a leverage measurement. Its a ratio. A 12 inch key with a capstan set back 6 inches is the same ratio as a 4 foot key with a capstan set back 2 feet. 

FW screws up inertia because you're going by DW to locate. An easy test to perform to show the flaw of FW  lets say DW is 50 grams you could use up to 200 grams near the balance pin to achieve a 50 gram DW. And pre- conceived FW schemes also do not work. Its only an illusion of balance because DW is smooth. How about the FW difference between sharps and naturals. That's can be an even inertia buster, as well as a couple of others.

When inertia is actually smooth its an incredible experience, because a subconscious micro - finger management of constant correction is gone.

-chris

Wow, 85 grams!!! Yipes

Contact me privately and I'll give you the info and the data I need to run numbers. I have a program I've been using for years that I'm beta testing with some other techs using their projects. It's a simple way to determine leverage/hammer weight compatibility and optimization and will give you  hammer weights, or strike weights, and the key leading to produce a target balance weight. Simple system that gives you the raw data you need to put together the action.

i would definitely turn the capstan to 90 degrees,  even if you used the same whole location, turning it to 90 degrees would lower the action ratio.

if you're familiar with Stanwood weigh off procedures for BW, FW and SW (or hammer weight is ok) that's helpful. 

I wouldn't worry about that.  It does happen fairly often.  I doubt it's by design but rather an execution error that probably relates to strike point determination, stack orientation followed by determining the capstan line last.  That system creates all kinds of problems with NY Steinways though I don't know the exactly procedure that Hamburg uses.  The key ratio being perfectly symmetrical from bass to treble is nice but not crucial and this difference is not huge and won't make that much difference in your final weight and balance. 

The ratio is a bit high though (depending on how you took the measurements) so I would certainly be using 17 mm shanks on this and it may be that the hammer weight will be a consideration even with that.  This can all be determined (if you're following my TW beta testing I'd be happy to run numbers for you).   

Question about key ratios. I am about to replace the angled capstans on a 95 year old Hamburg Steinway model M grand with straight WNG capstans. I find the straight line drifts 3 mm from the balance hole #1 at 117.5mm to 120.5mm at #88. The balance rail holes are located precisely the same distance from the back of the key at #1 and #88. Key ratio of the naturals from rep center to balance hole is 1:1.89 on #1 and 1:1.94 on #88. Could this be intentional or just a manufacturing error?

A cute but meaningless analogy.

Where the mass is located is extremely important in measuring its contribution to the overall inertia.  That's why drilling holes in wippens  is an exercise in futility.  The wippen contributes very little to the inertia, yet I see this done all the time. That's why taking lead out of an overleaded key to reduce inertia doesn't work.  That single key lead doesn't add much to the overall inertia.  Removing it just raises the minimum force required to actuate the key (also known as the downweight).  The primary source of inertia is hammer mass and its relationship to the action ratio.  I think you need a review of the basics Chris.

The practical purpose of knowing what is the prime source of inertia is so you can direct your efforts to where it will make a difference and not to where it doesn't.  That seems pretty practical to me. 

A hub cap is a component of an automobile, but it doesn't tell you how much gas is in the tank.

"200 gram" was an illustration which comes from a video i did several months back. I was showing the range of weight possibilities in a key based on its positioning.

https://www.youtube.com/watch?v=KT1494-cDFM

I also see no practical purpose for stating which mass is more important, or why its dissected like that. Just a weird way of thinking if you ask me. For calculating inertia, all mass and where they are located on the levers are all in the equation.

Thus a direct measurement instead of numerous indirect ones.

Have a good day.

-chris

Key ratio is a component of leverage.  When you calculate the overall leverage as the product of levers the key is one of those levers (hammer shank and hammer and wippen being the other two).  I don't find the key ratio particularly useful except as a sign post (reminds of that old saying "the sign points to Berlin but it doesn't go to Berlin") especially since I don't really use a calculation of AR in my system (or inertia for that matter).  But it tells you something since about the direction of the overall system. With Steinway pianos, and many others, the key ratio is the only real variable.  The hammer/shank lever is predictable with bore distance and knuckle hanging somewhat consistent and the wippen lever doesn't change either, though the capstan position under the wippen cushion can, certainly. 

While you are correct about lead placement skewing the results, try putting 200 grams of lead near the balance rail, good luck.  It's an unachievable hypothetical and something that no one would ever try, hopefully.  It's not a good example.  There's a practical limit to the options we have to install leads.  The lead contributes some to the inertia but less than you think.  The unleaded key contributes too, probably more than you think.  Putting more lead near the balance point (the Steinway "accelerated action") is questionable as a benefit because, as you suggest, it simply adds more mass to the key, though it's not quite that simple.  But the biggest driver of inertia is the overall leverage and the hammer mass.  

Ultimately, since you are looking for a smooth inertia curve (inertia is not uniform through the action either because of decreasing hammer mass) a smooth transition in the leading pattern is desirable. And with that the inertia always decreases as you ascend the scale.   And let's not forget that we don't actually play the keys at the end of the key where we measure things like DW and UW.  Our fingers are moving all over the keys, in and out, and every time that change in position happens the effective leverage changes and with it the inertia.  It's really pretty remarkable that the human brain, in spite of that, still has a perception of evenness, even though the action, as it is played with variable key contact points, is anything but.  

Key ratio screws up inertia by not being a leverage measurement. Its a ratio. A 12 inch key with a capstan set back 6 inches is the same ratio as a 4 foot key with a capstan set back 2 feet. 

FW screws up inertia because you're going by DW to locate. An easy test to perform to show the flaw of FW  lets say DW is 50 grams you could use up to 200 grams near the balance pin to achieve a 50 gram DW. And pre- conceived FW schemes also do not work. Its only an illusion of balance because DW is smooth. How about the FW difference between sharps and naturals. That's can be an even inertia buster, as well as a couple of others.

When inertia is actually smooth its an incredible experience, because a subconscious micro - finger management of constant correction is gone.

-chris

Wow, 85 grams!!! Yipes

Contact me privately and I'll give you the info and the data I need to run numbers. I have a program I've been using for years that I'm beta testing with some other techs using their projects. It's a simple way to determine leverage/hammer weight compatibility and optimization and will give you  hammer weights, or strike weights, and the key leading to produce a target balance weight. Simple system that gives you the raw data you need to put together the action.

i would definitely turn the capstan to 90 degrees,  even if you used the same whole location, turning it to 90 degrees would lower the action ratio.

if you're familiar with Stanwood weigh off procedures for BW, FW and SW (or hammer weight is ok) that's helpful. 

I wouldn't worry about that.  It does happen fairly often.  I doubt it's by design but rather an execution error that probably relates to strike point determination, stack orientation followed by determining the capstan line last.  That system creates all kinds of problems with NY Steinways though I don't know the exactly procedure that Hamburg uses.  The key ratio being perfectly symmetrical from bass to treble is nice but not crucial and this difference is not huge and won't make that much difference in your final weight and balance. 

The ratio is a bit high though (depending on how you took the measurements) so I would certainly be using 17 mm shanks on this and it may be that the hammer weight will be a consideration even with that.  This can all be determined (if you're following my TW beta testing I'd be happy to run numbers for you).   

Question about key ratios. I am about to replace the angled capstans on a 95 year old Hamburg Steinway model M grand with straight WNG capstans. I find the straight line drifts 3 mm from the balance hole #1 at 117.5mm to 120.5mm at #88. The balance rail holes are located precisely the same distance from the back of the key at #1 and #88. Key ratio of the naturals from rep center to balance hole is 1:1.89 on #1 and 1:1.94 on #88. Could this be intentional or just a manufacturing error?

Question about key ratios. I am about to replace the angled capstans on a 95 year old Hamburg Steinway model M grand with straight WNG capstans. I find the straight line drifts 3 mm from the balance hole #1 at 117.5mm to 120.5mm at #88. The balance rail holes are located precisely the same distance from the back of the key at #1 and #88. Key ratio of the naturals from rep center to balance hole is 1:1.89 on #1 and 1:1.94 on #88. Could this be intentional or just a manufacturing error?

Everyone involved in this touchweight/key ratio/action ratio/inertia/momentum discussion might enjoy a class next week at our annual convention in Arlington, VA titled "Weigh-Off 101". I understand from the two instructors it will get deeper into these topics than merely a "101" approach, though all the basics will be covered, too. Some eye-opening examples of exactly where the lead can (should?) be placed along the length of the keystick will be included. Oh boy, I'll be in the front row!

David G. Hughes, RPT

Baltimore Chapter 

Question about key ratios. I am about to replace the angled capstans on a 95 year old Hamburg Steinway model M grand with straight WNG capstans. I find the straight line drifts 3 mm from the balance hole #1 at 117.5mm to 120.5mm at #88. The balance rail holes are located precisely the same distance from the back of the key at #1 and #88. Key ratio of the naturals from rep center to balance hole is 1:1.89 on #1 and 1:1.94 on #88. Could this be intentional or just a manufacturing error?

Thanks David. Who are the two instructors?  Not going, unfortunately

Everyone involved in this touchweight/key ratio/action ratio/inertia/momentum discussion might enjoy a class next week at our annual convention in Arlington, VA titled "Weigh-Off 101". I understand from the two instructors it will get deeper into these topics than merely a "101" approach, though all the basics will be covered, too. Some eye-opening examples of exactly where the lead can (should?) be placed along the length of the keystick will be included. Oh boy, I'll be in the front row!

David G. Hughes, RPT

Baltimore Chapter 

Question about key ratios. I am about to replace the angled capstans on a 95 year old Hamburg Steinway model M grand with straight WNG capstans. I find the straight line drifts 3 mm from the balance hole #1 at 117.5mm to 120.5mm at #88. The balance rail holes are located precisely the same distance from the back of the key at #1 and #88. Key ratio of the naturals from rep center to balance hole is 1:1.89 on #1 and 1:1.94 on #88. Could this be intentional or just a manufacturing error?

Replying to David Love, message #12: I believe the two instructors are Dean Reyburn and some guy named Hughes something.

Thanks David. Who are the two instructors?  Not going, unfortunately

Everyone involved in this touchweight/key ratio/action ratio/inertia/momentum discussion might enjoy a class next week at our annual convention in Arlington, VA titled "Weigh-Off 101". I understand from the two instructors it will get deeper into these topics than merely a "101" approach, though all the basics will be covered, too. Some eye-opening examples of exactly where the lead can (should?) be placed along the length of the keystick will be included. Oh boy, I'll be in the front row!

David G. Hughes, RPT

Baltimore Chapter 

Question about key ratios. I am about to replace the angled capstans on a 95 year old Hamburg Steinway model M grand with straight WNG capstans. I find the straight line drifts 3 mm from the balance hole #1 at 117.5mm to 120.5mm at #88. The balance rail holes are located precisely the same distance from the back of the key at #1 and #88. Key ratio of the naturals from rep center to balance hole is 1:1.89 on #1 and 1:1.94 on #88. Could this be intentional or just a manufacturing error?

David H, I guess that explains why you'll be in the front row. 😂 See you at convention!

Replying to David Love, message #12: I believe the two instructors are Dean Reyburn and some guy named Hughes something.

Thanks David. Who are the two instructors?  Not going, unfortunately

Everyone involved in this touchweight/key ratio/action ratio/inertia/momentum discussion might enjoy a class next week at our annual convention in Arlington, VA titled "Weigh-Off 101". I understand from the two instructors it will get deeper into these topics than merely a "101" approach, though all the basics will be covered, too. Some eye-opening examples of exactly where the lead can (should?) be placed along the length of the keystick will be included. Oh boy, I'll be in the front row!

David G. Hughes, RPT

Baltimore Chapter 

Question about key ratios. I am about to replace the angled capstans on a 95 year old Hamburg Steinway model M grand with straight WNG capstans. I find the straight line drifts 3 mm from the balance hole #1 at 117.5mm to 120.5mm at #88. The balance rail holes are located precisely the same distance from the back of the key at #1 and #88. Key ratio of the naturals from rep center to balance hole is 1:1.89 on #1 and 1:1.94 on #88. Could this be intentional or just a manufacturing error?

Replying to David Love, message #12: I believe the two instructors are Dean Reyburn and some guy named Hughes something.

Thanks David. Who are the two instructors?  Not going, unfortunately

Everyone involved in this touchweight/key ratio/action ratio/inertia/momentum discussion might enjoy a class next week at our annual convention in Arlington, VA titled "Weigh-Off 101". I understand from the two instructors it will get deeper into these topics than merely a "101" approach, though all the basics will be covered, too. Some eye-opening examples of exactly where the lead can (should?) be placed along the length of the keystick will be included. Oh boy, I'll be in the front row!

David G. Hughes, RPT

Baltimore Chapter 

Question about key ratios. I am about to replace the angled capstans on a 95 year old Hamburg Steinway model M grand with straight WNG capstans. I find the straight line drifts 3 mm from the balance hole #1 at 117.5mm to 120.5mm at #88. The balance rail holes are located precisely the same distance from the back of the key at #1 and #88. Key ratio of the naturals from rep center to balance hole is 1:1.89 on #1 and 1:1.94 on #88. Could this be intentional or just a manufacturing error?

David H

Sounds like a class not to be missed.  My beta testing is more to do with determining optimum hammer weight and then calculating a specific note for note weight curve based on the set you are choosing (rather than a somewhat predetermined "zone") and then the accompanying calculated FW curve to yield a specific BW that you choose.  From those numbers I can tell if you have an inertia problem or not (either too much or not enough).   It achieves that without having to measure action ratios at all, something most techs don't seem that comfortable with plus there's an inconsistency in measurement styles and what certain ARs mean in different methods. 

But once you have those two weight curves then where to place the leads (if you're starting from scratch which most of us aren't) is certainly in interesting topic.  It's been addressed in the past as it relates to key return (the accelerated action) but in spite of that slight benefit it's interesting to note that Steinway abandoned the more leads nearer the balance pin approach in favor of the 3-2-1-0 approach of the past.  

Interesting topic though.  Sorry I can't be there.  

Replying to David Love, message #12: I believe the two instructors are Dean Reyburn and some guy named Hughes something.

Thanks David. Who are the two instructors?  Not going, unfortunately

Everyone involved in this touchweight/key ratio/action ratio/inertia/momentum discussion might enjoy a class next week at our annual convention in Arlington, VA titled "Weigh-Off 101". I understand from the two instructors it will get deeper into these topics than merely a "101" approach, though all the basics will be covered, too. Some eye-opening examples of exactly where the lead can (should?) be placed along the length of the keystick will be included. Oh boy, I'll be in the front row!

David G. Hughes, RPT

Baltimore Chapter 

Question about key ratios. I am about to replace the angled capstans on a 95 year old Hamburg Steinway model M grand with straight WNG capstans. I find the straight line drifts 3 mm from the balance hole #1 at 117.5mm to 120.5mm at #88. The balance rail holes are located precisely the same distance from the back of the key at #1 and #88. Key ratio of the naturals from rep center to balance hole is 1:1.89 on #1 and 1:1.94 on #88. Could this be intentional or just a manufacturing error?

One problem with using FW as a measure. Lets say you have 10 keys with 2 leads each. because the hammer gets lights you have to slide them backwards so they have less effect. This is an admission a lighter weight would do the same thing.

That's just one way FW screws up inertia. 

Also, saying an action is light, medium, or heavy is not inertia control. Those are ballpark guesses that use terms that are relative. Its equivalent to saying that a weighted wheel will reach the bottom of a hill slowly, in due time, or quickly. Because i use inertia as a direct measure, i can say the weighted wheel will reach the bottom in 10 seconds. With that capability inertia can be communicated to others precisely, duplicated, and the smoothness across the compass controlled unlike what you can do with FW based systems.

-chris

-chris

David H

Sounds like a class not to be missed.  My beta testing is more to do with determining optimum hammer weight and then calculating a specific note for note weight curve based on the set you are choosing (rather than a somewhat predetermined "zone") and then the accompanying calculated FW curve to yield a specific BW that you choose.  From those numbers I can tell if you have an inertia problem or not (either too much or not enough).   It achieves that without having to measure action ratios at all, something most techs don't seem that comfortable with plus there's an inconsistency in measurement styles and what certain ARs mean in different methods. 

But once you have those two weight curves then where to place the leads (if you're starting from scratch which most of us aren't) is certainly in interesting topic.  It's been addressed in the past as it relates to key return (the accelerated action) but in spite of that slight benefit it's interesting to note that Steinway abandoned the more leads nearer the balance pin approach in favor of the 3-2-1-0 approach of the past.  

Interesting topic though.  Sorry I can't be there.  

Replying to David Love, message #12: I believe the two instructors are Dean Reyburn and some guy named Hughes something.

Thanks David. Who are the two instructors?  Not going, unfortunately

Everyone involved in this touchweight/key ratio/action ratio/inertia/momentum discussion might enjoy a class next week at our annual convention in Arlington, VA titled "Weigh-Off 101". I understand from the two instructors it will get deeper into these topics than merely a "101" approach, though all the basics will be covered, too. Some eye-opening examples of exactly where the lead can (should?) be placed along the length of the keystick will be included. Oh boy, I'll be in the front row!

David G. Hughes, RPT

Baltimore Chapter 

Question about key ratios. I am about to replace the angled capstans on a 95 year old Hamburg Steinway model M grand with straight WNG capstans. I find the straight line drifts 3 mm from the balance hole #1 at 117.5mm to 120.5mm at #88. The balance rail holes are located precisely the same distance from the back of the key at #1 and #88. Key ratio of the naturals from rep center to balance hole is 1:1.89 on #1 and 1:1.94 on #88. Could this be intentional or just a manufacturing error?

Chris

I read this 3+ times. I really tried. I even tried altering the 'em-PHA-sis on different syl-LA-bles. I still have no idea what you're talking about. But don't try again on my account, please. 

One problem with using FW as a measure. Lets say you have 10 keys with 2 leads each. because the hammer gets lights you have to slide them backwards so they have less effect. This is an admission a lighter weight would do the same thing.

That's just one way FW screws up inertia. 

Also, saying an action is light, medium, or heavy is not inertia control. Those are ballpark guesses that use terms that are relative. Its equivalent to saying that a weighted wheel will reach the bottom of a hill slowly, in due time, or quickly. Because i use inertia as a direct measure, i can say the weighted wheel will reach the bottom in 10 seconds. With that capability inertia can be communicated to others precisely, duplicated, and the smoothness across the compass controlled unlike what you can do with FW based systems.

-chris

-chris

David H

Sounds like a class not to be missed.  My beta testing is more to do with determining optimum hammer weight and then calculating a specific note for note weight curve based on the set you are choosing (rather than a somewhat predetermined "zone") and then the accompanying calculated FW curve to yield a specific BW that you choose.  From those numbers I can tell if you have an inertia problem or not (either too much or not enough).   It achieves that without having to measure action ratios at all, something most techs don't seem that comfortable with plus there's an inconsistency in measurement styles and what certain ARs mean in different methods. 

But once you have those two weight curves then where to place the leads (if you're starting from scratch which most of us aren't) is certainly in interesting topic.  It's been addressed in the past as it relates to key return (the accelerated action) but in spite of that slight benefit it's interesting to note that Steinway abandoned the more leads nearer the balance pin approach in favor of the 3-2-1-0 approach of the past.  

Interesting topic though.  Sorry I can't be there.  

Replying to David Love, message #12: I believe the two instructors are Dean Reyburn and some guy named Hughes something.

Thanks David. Who are the two instructors?  Not going, unfortunately

Everyone involved in this touchweight/key ratio/action ratio/inertia/momentum discussion might enjoy a class next week at our annual convention in Arlington, VA titled "Weigh-Off 101". I understand from the two instructors it will get deeper into these topics than merely a "101" approach, though all the basics will be covered, too. Some eye-opening examples of exactly where the lead can (should?) be placed along the length of the keystick will be included. Oh boy, I'll be in the front row!

David G. Hughes, RPT

Baltimore Chapter 

Question about key ratios. I am about to replace the angled capstans on a 95 year old Hamburg Steinway model M grand with straight WNG capstans. I find the straight line drifts 3 mm from the balance hole #1 at 117.5mm to 120.5mm at #88. The balance rail holes are located precisely the same distance from the back of the key at #1 and #88. Key ratio of the naturals from rep center to balance hole is 1:1.89 on #1 and 1:1.94 on #88. Could this be intentional or just a manufacturing error?

Its a public forum David, i didn't write it to you specifically in the first place.

I guess i should put "to all" from now on.

To all,

When a weight is being slid along a key to match a DW target or a FW target on a scale, it is equivalent to sliding a hammer along the shank to get a SW target. Both methods are/would be using leverage disadvantageously and at the cost of controlling the mass and inertia.

-chris

Chris

I read this 3+ times. I really tried. I even tried altering the 'em-PHA-sis on different syl-LA-bles. I still have no idea what you're talking about. But don't try again on my account, please. 

One problem with using FW as a measure. Lets say you have 10 keys with 2 leads each. because the hammer gets lights you have to slide them backwards so they have less effect. This is an admission a lighter weight would do the same thing.

That's just one way FW screws up inertia. 

Also, saying an action is light, medium, or heavy is not inertia control. Those are ballpark guesses that use terms that are relative. Its equivalent to saying that a weighted wheel will reach the bottom of a hill slowly, in due time, or quickly. Because i use inertia as a direct measure, i can say the weighted wheel will reach the bottom in 10 seconds. With that capability inertia can be communicated to others precisely, duplicated, and the smoothness across the compass controlled unlike what you can do with FW based systems.

-chris

-chris

David H

Sounds like a class not to be missed.  My beta testing is more to do with determining optimum hammer weight and then calculating a specific note for note weight curve based on the set you are choosing (rather than a somewhat predetermined "zone") and then the accompanying calculated FW curve to yield a specific BW that you choose.  From those numbers I can tell if you have an inertia problem or not (either too much or not enough).   It achieves that without having to measure action ratios at all, something most techs don't seem that comfortable with plus there's an inconsistency in measurement styles and what certain ARs mean in different methods. 

But once you have those two weight curves then where to place the leads (if you're starting from scratch which most of us aren't) is certainly in interesting topic.  It's been addressed in the past as it relates to key return (the accelerated action) but in spite of that slight benefit it's interesting to note that Steinway abandoned the more leads nearer the balance pin approach in favor of the 3-2-1-0 approach of the past.  

Interesting topic though.  Sorry I can't be there.  

Replying to David Love, message #12: I believe the two instructors are Dean Reyburn and some guy named Hughes something.

Thanks David. Who are the two instructors?  Not going, unfortunately

Everyone involved in this touchweight/key ratio/action ratio/inertia/momentum discussion might enjoy a class next week at our annual convention in Arlington, VA titled "Weigh-Off 101". I understand from the two instructors it will get deeper into these topics than merely a "101" approach, though all the basics will be covered, too. Some eye-opening examples of exactly where the lead can (should?) be placed along the length of the keystick will be included. Oh boy, I'll be in the front row!

David G. Hughes, RPT

Baltimore Chapter 

Question about key ratios. I am about to replace the angled capstans on a 95 year old Hamburg Steinway model M grand with straight WNG capstans. I find the straight line drifts 3 mm from the balance hole #1 at 117.5mm to 120.5mm at #88. The balance rail holes are located precisely the same distance from the back of the key at #1 and #88. Key ratio of the naturals from rep center to balance hole is 1:1.89 on #1 and 1:1.94 on #88. Could this be intentional or just a manufacturing error?

To All

I still don't know what Chris is talking about. It makes no sense. Maybe someone else can explain it to me. There's no equivalence to the examples he gave. It's like asking for further explanation and having the person repeat what they said but louder. 

------------------------------
David Love RPT
www.davidlovepianos.com
davidlovepianos@comcast.net
415 407 8320

Original Message:
Sent: 07-28-2023 09:03
From: Chris Chernobieff
Subject: Key ratio

Its a public forum David, i didn't write it to you specifically in the first place.

I guess i should put "to all" from now on.

To all,

When a weight is being slid along a key to match a DW target or a FW target on a scale, it is equivalent to sliding a hammer along the shank to get a SW target. Both methods are/would be using leverage disadvantageously and at the cost of controlling the mass and inertia.

-chris

------------------------------
Chernobieff Piano Restorations
All the elements are known, and yet no combination there of creates life. Yet we are here.
865-986-7720 (text only please)

Original Message:
Sent: 07-28-2023 01:48
From: David Love
Subject: Key ratio

Chris

I read this 3+ times. I really tried. I even tried altering the 'em-PHA-sis on different syl-LA-bles. I still have no idea what you're talking about. But don't try again on my account, please. 

------------------------------
David Love RPT
www.davidlovepianos.com
davidlovepianos@comcast.net
415 407 8320

Original Message:
Sent: 07-28-2023 01:09
From: Chris Chernobieff
Subject: Key ratio

One problem with using FW as a measure. Lets say you have 10 keys with 2 leads each. because the hammer gets lights you have to slide them backwards so they have less effect. This is an admission a lighter weight would do the same thing.

That's just one way FW screws up inertia. 

Also, saying an action is light, medium, or heavy is not inertia control. Those are ballpark guesses that use terms that are relative. Its equivalent to saying that a weighted wheel will reach the bottom of a hill slowly, in due time, or quickly. Because i use inertia as a direct measure, i can say the weighted wheel will reach the bottom in 10 seconds. With that capability inertia can be communicated to others precisely, duplicated, and the smoothness across the compass controlled unlike what you can do with FW based systems.

-chris

-chris

------------------------------
Chernobieff Piano Restorations
All the elements are known, and yet no combination there of creates life. Yet we are here.
865-986-7720 (text only please)

Original Message:
Sent: 07-24-2023 13:06
From: David Love
Subject: Key ratio

David H

Sounds like a class not to be missed.  My beta testing is more to do with determining optimum hammer weight and then calculating a specific note for note weight curve based on the set you are choosing (rather than a somewhat predetermined "zone") and then the accompanying calculated FW curve to yield a specific BW that you choose.  From those numbers I can tell if you have an inertia problem or not (either too much or not enough).   It achieves that without having to measure action ratios at all, something most techs don't seem that comfortable with plus there's an inconsistency in measurement styles and what certain ARs mean in different methods. 

But once you have those two weight curves then where to place the leads (if you're starting from scratch which most of us aren't) is certainly in interesting topic.  It's been addressed in the past as it relates to key return (the accelerated action) but in spite of that slight benefit it's interesting to note that Steinway abandoned the more leads nearer the balance pin approach in favor of the 3-2-1-0 approach of the past.  

Interesting topic though.  Sorry I can't be there.  

------------------------------
David Love RPT
www.davidlovepianos.com
davidlovepianos@comcast.net
415 407 8320

Original Message:
Sent: 07-23-2023 07:45
From: David Hughes
Subject: Key ratio

Replying to David Love, message #12: I believe the two instructors are Dean Reyburn and some guy named Hughes something.

------------------------------
David Hughes RPT
Vintage Case Parts
Glyndon MD
(443) 522-2201

Original Message:
Sent: 07-23-2023 00:03
From: David Love
Subject: Key ratio

Thanks David. Who are the two instructors?  Not going, unfortunately

------------------------------
David Love RPT
www.davidlovepianos.com
davidlovepianos@comcast.net
415 407 8320

Original Message:
Sent: 07-21-2023 09:28
From: David Hughes
Subject: Key ratio

Everyone involved in this touchweight/key ratio/action ratio/inertia/momentum discussion might enjoy a class next week at our annual convention in Arlington, VA titled "Weigh-Off 101". I understand from the two instructors it will get deeper into these topics than merely a "101" approach, though all the basics will be covered, too. Some eye-opening examples of exactly where the lead can (should?) be placed along the length of the keystick will be included. Oh boy, I'll be in the front row!

David G. Hughes, RPT

Baltimore Chapter 

------------------------------
David Hughes RPT
Vintage Case Parts
Glyndon MD
(443) 522-2201

Original Message:
Sent: 07-18-2023 10:57
From: Dave Conte
Subject: Key ratio

Question about key ratios. I am about to replace the angled capstans on a 95 year old Hamburg Steinway model M grand with straight WNG capstans. I find the straight line drifts 3 mm from the balance hole #1 at 117.5mm to 120.5mm at #88. The balance rail holes are located precisely the same distance from the back of the key at #1 and #88. Key ratio of the naturals from rep center to balance hole is 1:1.89 on #1 and 1:1.94 on #88. Could this be intentional or just a manufacturing error?

------------------------------
Dave Conte, RPT

Piano Technician in Residence
The University of Tennessee
College of Music
Knoxville TN
(817) 307-5656
Owner: Rocky Top Piano
------------------------------

Let me just add:

Chris wrote:

"When a weight is being slid along a key to match a DW target or a FW target on a scale, it is equivalent to sliding a hammer along the shank to get a SW target."

That is completely and utterly false.  Moving the hammer in on the shank to achieve a SW target changes the output on the hammer/shank assembly lever and with it the overall action ratio.  Sliding a lead along the key to achieve a specific FW target has no effect on the action ratio, zero, zip. That's a very major difference and your comment belies a fundamental understanding of this process. 

Since inertia in the system is largely a function of the AR (leverage) and mass it's trying to move (and where that mass is located), no matter how many leads you put in a key the AR remains unchanged and the relationship between AR and hammers mass remains unchanged.  The added leads required to achieve a certain BW or FW (however you want to think about it) will, to some degree, add to the inertia but the inertia problem that exists in many overleaded keyboards is not because of the excess lead, rather it's the poor relationship between the AR and hammer mass (which we refer to as SW in the Stanwood system) that is responsible for the major part of that.  The excess lead contributes some but pales in comparison to the AR/SW relationship and removing lead will not fix that problem.  Excess leading (or very high FWs) simply tell us that there's a problem.  The only way to fix a high inertia situation is to either lower the AR or lower the SW, or some combination of both. 

In the model I am using one can infer that AR/SW relationship using FW, SW, BW data to see if you have a problem, plus I can tell you what needs to be modified and by how much.  Since most of us don't work with inertia formulas because they don't give us much in terms of practical solutions (how much should I change the SW or AR by to achieve my goal), it's not very useful.  I know some programs, like Gravagne's, give an inertia number but it's of little value other than curiosity for the nerds. (Last I checked Gravagne was also still using "downweight" which doesn't tease out the friction variability and thus is somewhat antiquated.)  That's especially true because the inertia in all pianos graduates from relatively high to relatively low from bottom to top of the scale since the hammers are always decreasing in mass and, generally, the AR is remaining constant, or fairly constant.  Because of that fact the Fandrich/Rhodes system used A4 as their target note for evaluation of the entire action.  Those same formulas (whatever it was that they used) would yield something quite different if a target was chosen higher or lower in the scale and would have to be modified accordingly.

------------------------------
David Love RPT
www.davidlovepianos.com
davidlovepianos@comcast.net
415 407 8320

Original Message:
Sent: 07-28-2023 12:34
From: David Love
Subject: Key ratio

To All

I still don't know what Chris is talking about. It makes no sense. Maybe someone else can explain it to me. There's no equivalence to the examples he gave. It's like asking for further explanation and having the person repeat what they said but louder. 

------------------------------
David Love RPT
www.davidlovepianos.com
davidlovepianos@comcast.net
415 407 8320

Original Message:
Sent: 07-28-2023 09:03
From: Chris Chernobieff
Subject: Key ratio

Its a public forum David, i didn't write it to you specifically in the first place.

I guess i should put "to all" from now on.

To all,

When a weight is being slid along a key to match a DW target or a FW target on a scale, it is equivalent to sliding a hammer along the shank to get a SW target. Both methods are/would be using leverage disadvantageously and at the cost of controlling the mass and inertia.

-chris

------------------------------
Chernobieff Piano Restorations
All the elements are known, and yet no combination there of creates life. Yet we are here.
865-986-7720 (text only please)

Original Message:
Sent: 07-28-2023 01:48
From: David Love
Subject: Key ratio

Chris

I read this 3+ times. I really tried. I even tried altering the 'em-PHA-sis on different syl-LA-bles. I still have no idea what you're talking about. But don't try again on my account, please. 

------------------------------
David Love RPT
www.davidlovepianos.com
davidlovepianos@comcast.net
415 407 8320

Original Message:
Sent: 07-28-2023 01:09
From: Chris Chernobieff
Subject: Key ratio

One problem with using FW as a measure. Lets say you have 10 keys with 2 leads each. because the hammer gets lights you have to slide them backwards so they have less effect. This is an admission a lighter weight would do the same thing.

That's just one way FW screws up inertia. 

Also, saying an action is light, medium, or heavy is not inertia control. Those are ballpark guesses that use terms that are relative. Its equivalent to saying that a weighted wheel will reach the bottom of a hill slowly, in due time, or quickly. Because i use inertia as a direct measure, i can say the weighted wheel will reach the bottom in 10 seconds. With that capability inertia can be communicated to others precisely, duplicated, and the smoothness across the compass controlled unlike what you can do with FW based systems.

-chris

-chris

------------------------------
Chernobieff Piano Restorations
All the elements are known, and yet no combination there of creates life. Yet we are here.
865-986-7720 (text only please)

Original Message:
Sent: 07-24-2023 13:06
From: David Love
Subject: Key ratio

David H

Sounds like a class not to be missed.  My beta testing is more to do with determining optimum hammer weight and then calculating a specific note for note weight curve based on the set you are choosing (rather than a somewhat predetermined "zone") and then the accompanying calculated FW curve to yield a specific BW that you choose.  From those numbers I can tell if you have an inertia problem or not (either too much or not enough).   It achieves that without having to measure action ratios at all, something most techs don't seem that comfortable with plus there's an inconsistency in measurement styles and what certain ARs mean in different methods. 

But once you have those two weight curves then where to place the leads (if you're starting from scratch which most of us aren't) is certainly in interesting topic.  It's been addressed in the past as it relates to key return (the accelerated action) but in spite of that slight benefit it's interesting to note that Steinway abandoned the more leads nearer the balance pin approach in favor of the 3-2-1-0 approach of the past.  

Interesting topic though.  Sorry I can't be there.  

------------------------------
David Love RPT
www.davidlovepianos.com
davidlovepianos@comcast.net
415 407 8320

Original Message:
Sent: 07-23-2023 07:45
From: David Hughes
Subject: Key ratio

Replying to David Love, message #12: I believe the two instructors are Dean Reyburn and some guy named Hughes something.

------------------------------
David Hughes RPT
Vintage Case Parts
Glyndon MD
(443) 522-2201

Original Message:
Sent: 07-23-2023 00:03
From: David Love
Subject: Key ratio

Thanks David. Who are the two instructors?  Not going, unfortunately

------------------------------
David Love RPT
www.davidlovepianos.com
davidlovepianos@comcast.net
415 407 8320

Original Message:
Sent: 07-21-2023 09:28
From: David Hughes
Subject: Key ratio

Everyone involved in this touchweight/key ratio/action ratio/inertia/momentum discussion might enjoy a class next week at our annual convention in Arlington, VA titled "Weigh-Off 101". I understand from the two instructors it will get deeper into these topics than merely a "101" approach, though all the basics will be covered, too. Some eye-opening examples of exactly where the lead can (should?) be placed along the length of the keystick will be included. Oh boy, I'll be in the front row!

David G. Hughes, RPT

Baltimore Chapter 

------------------------------
David Hughes RPT
Vintage Case Parts
Glyndon MD
(443) 522-2201

Original Message:
Sent: 07-18-2023 10:57
From: Dave Conte
Subject: Key ratio

Question about key ratios. I am about to replace the angled capstans on a 95 year old Hamburg Steinway model M grand with straight WNG capstans. I find the straight line drifts 3 mm from the balance hole #1 at 117.5mm to 120.5mm at #88. The balance rail holes are located precisely the same distance from the back of the key at #1 and #88. Key ratio of the naturals from rep center to balance hole is 1:1.89 on #1 and 1:1.94 on #88. Could this be intentional or just a manufacturing error?

------------------------------
Dave Conte, RPT

Piano Technician in Residence
The University of Tennessee
College of Music
Knoxville TN
(817) 307-5656
Owner: Rocky Top Piano
------------------------------

All,

I'll address two fallacies (AR and FW).

Action Ratio is NOT a component of Leverage. Because you can change the leverage and keep the same action ratio. Its just not a reliable measurement for calculating leverage. For calculating leverage accurately, you simply want the actual lengths of the parts.

Front weight. When you slide a weight backwards towards the balance rail, you are reducing the effect of the leveraged mass to manipulate down weight. So as neighboring hammers get lighter a weight gets slid further back instead of being reduced. Plus, another problem with FW is that it accepts the varying weight of the parts themselves That's why the leads often end up in non sequential locations.

Using these two inaccurate means of measurement leads to unpredictable results when different masses and leverages occur from piano to piano. Using inertia as a measurement provides a consistent numbering system that every touch of every piano can conform to.

-chris

------------------------------
Chernobieff Piano Restorations
All the elements are known, and yet no combination there of creates life. Yet we are here.
865-986-7720 (text only please)

Original Message:
Sent: 07-28-2023 14:00
From: David Love
Subject: Key ratio

Let me just add:

Chris wrote:

"When a weight is being slid along a key to match a DW target or a FW target on a scale, it is equivalent to sliding a hammer along the shank to get a SW target."

That is completely and utterly false.  Moving the hammer in on the shank to achieve a SW target changes the output on the hammer/shank assembly lever and with it the overall action ratio.  Sliding a lead along the key to achieve a specific FW target has no effect on the action ratio, zero, zip. That's a very major difference and your comment belies a fundamental understanding of this process. 

Since inertia in the system is largely a function of the AR (leverage) and mass it's trying to move (and where that mass is located), no matter how many leads you put in a key the AR remains unchanged and the relationship between AR and hammers mass remains unchanged.  The added leads required to achieve a certain BW or FW (however you want to think about it) will, to some degree, add to the inertia but the inertia problem that exists in many overleaded keyboards is not because of the excess lead, rather it's the poor relationship between the AR and hammer mass (which we refer to as SW in the Stanwood system) that is responsible for the major part of that.  The excess lead contributes some but pales in comparison to the AR/SW relationship and removing lead will not fix that problem.  Excess leading (or very high FWs) simply tell us that there's a problem.  The only way to fix a high inertia situation is to either lower the AR or lower the SW, or some combination of both. 

In the model I am using one can infer that AR/SW relationship using FW, SW, BW data to see if you have a problem, plus I can tell you what needs to be modified and by how much.  Since most of us don't work with inertia formulas because they don't give us much in terms of practical solutions (how much should I change the SW or AR by to achieve my goal), it's not very useful.  I know some programs, like Gravagne's, give an inertia number but it's of little value other than curiosity for the nerds. (Last I checked Gravagne was also still using "downweight" which doesn't tease out the friction variability and thus is somewhat antiquated.)  That's especially true because the inertia in all pianos graduates from relatively high to relatively low from bottom to top of the scale since the hammers are always decreasing in mass and, generally, the AR is remaining constant, or fairly constant.  Because of that fact the Fandrich/Rhodes system used A4 as their target note for evaluation of the entire action.  Those same formulas (whatever it was that they used) would yield something quite different if a target was chosen higher or lower in the scale and would have to be modified accordingly.

------------------------------
David Love RPT
www.davidlovepianos.com
davidlovepianos@comcast.net
415 407 8320

Original Message:
Sent: 07-28-2023 12:34
From: David Love
Subject: Key ratio

To All

I still don't know what Chris is talking about. It makes no sense. Maybe someone else can explain it to me. There's no equivalence to the examples he gave. It's like asking for further explanation and having the person repeat what they said but louder. 

------------------------------
David Love RPT
www.davidlovepianos.com
davidlovepianos@comcast.net
415 407 8320

Original Message:
Sent: 07-28-2023 09:03
From: Chris Chernobieff
Subject: Key ratio

Its a public forum David, i didn't write it to you specifically in the first place.

I guess i should put "to all" from now on.

To all,

When a weight is being slid along a key to match a DW target or a FW target on a scale, it is equivalent to sliding a hammer along the shank to get a SW target. Both methods are/would be using leverage disadvantageously and at the cost of controlling the mass and inertia.

-chris

------------------------------
Chernobieff Piano Restorations
All the elements are known, and yet no combination there of creates life. Yet we are here.
865-986-7720 (text only please)

Original Message:
Sent: 07-28-2023 01:48
From: David Love
Subject: Key ratio

Chris

I read this 3+ times. I really tried. I even tried altering the 'em-PHA-sis on different syl-LA-bles. I still have no idea what you're talking about. But don't try again on my account, please. 

------------------------------
David Love RPT
www.davidlovepianos.com
davidlovepianos@comcast.net
415 407 8320

Original Message:
Sent: 07-28-2023 01:09
From: Chris Chernobieff
Subject: Key ratio

One problem with using FW as a measure. Lets say you have 10 keys with 2 leads each. because the hammer gets lights you have to slide them backwards so they have less effect. This is an admission a lighter weight would do the same thing.

That's just one way FW screws up inertia. 

Also, saying an action is light, medium, or heavy is not inertia control. Those are ballpark guesses that use terms that are relative. Its equivalent to saying that a weighted wheel will reach the bottom of a hill slowly, in due time, or quickly. Because i use inertia as a direct measure, i can say the weighted wheel will reach the bottom in 10 seconds. With that capability inertia can be communicated to others precisely, duplicated, and the smoothness across the compass controlled unlike what you can do with FW based systems.

-chris

-chris

------------------------------
Chernobieff Piano Restorations
All the elements are known, and yet no combination there of creates life. Yet we are here.
865-986-7720 (text only please)

Original Message:
Sent: 07-24-2023 13:06
From: David Love
Subject: Key ratio

David H

Sounds like a class not to be missed.  My beta testing is more to do with determining optimum hammer weight and then calculating a specific note for note weight curve based on the set you are choosing (rather than a somewhat predetermined "zone") and then the accompanying calculated FW curve to yield a specific BW that you choose.  From those numbers I can tell if you have an inertia problem or not (either too much or not enough).   It achieves that without having to measure action ratios at all, something most techs don't seem that comfortable with plus there's an inconsistency in measurement styles and what certain ARs mean in different methods. 

But once you have those two weight curves then where to place the leads (if you're starting from scratch which most of us aren't) is certainly in interesting topic.  It's been addressed in the past as it relates to key return (the accelerated action) but in spite of that slight benefit it's interesting to note that Steinway abandoned the more leads nearer the balance pin approach in favor of the 3-2-1-0 approach of the past.  

Interesting topic though.  Sorry I can't be there.  

------------------------------
David Love RPT
www.davidlovepianos.com
davidlovepianos@comcast.net
415 407 8320

Original Message:
Sent: 07-23-2023 07:45
From: David Hughes
Subject: Key ratio

Replying to David Love, message #12: I believe the two instructors are Dean Reyburn and some guy named Hughes something.

------------------------------
David Hughes RPT
Vintage Case Parts
Glyndon MD
(443) 522-2201

Original Message:
Sent: 07-23-2023 00:03
From: David Love
Subject: Key ratio

Thanks David. Who are the two instructors?  Not going, unfortunately

------------------------------
David Love RPT
www.davidlovepianos.com
davidlovepianos@comcast.net
415 407 8320

Original Message:
Sent: 07-21-2023 09:28
From: David Hughes
Subject: Key ratio

Everyone involved in this touchweight/key ratio/action ratio/inertia/momentum discussion might enjoy a class next week at our annual convention in Arlington, VA titled "Weigh-Off 101". I understand from the two instructors it will get deeper into these topics than merely a "101" approach, though all the basics will be covered, too. Some eye-opening examples of exactly where the lead can (should?) be placed along the length of the keystick will be included. Oh boy, I'll be in the front row!

David G. Hughes, RPT

Baltimore Chapter 

------------------------------
David Hughes RPT
Vintage Case Parts
Glyndon MD
(443) 522-2201

Original Message:
Sent: 07-18-2023 10:57
From: Dave Conte
Subject: Key ratio

Question about key ratios. I am about to replace the angled capstans on a 95 year old Hamburg Steinway model M grand with straight WNG capstans. I find the straight line drifts 3 mm from the balance hole #1 at 117.5mm to 120.5mm at #88. The balance rail holes are located precisely the same distance from the back of the key at #1 and #88. Key ratio of the naturals from rep center to balance hole is 1:1.89 on #1 and 1:1.94 on #88. Could this be intentional or just a manufacturing error?

------------------------------
Dave Conte, RPT

Piano Technician in Residence
The University of Tennessee
College of Music
Knoxville TN
(817) 307-5656
Owner: Rocky Top Piano
------------------------------

In this discussion leverage, referring to the mechanical advantage gained by using a lever, or series of levers as you see in a piano, to magnify the force applied to an object and action ratio are used interchangeably.  If you change the AR, the product of those three levers, you necessarily change the mechanical advantage. That's just a physical fact.

Please explain to me how you can change one and not the other. I'll make it simple, let's just talk about the key lever, a simple Teeter-Totter with a 1:1 ratio (fulcrum in the middle). Please show me how you can move the fulcrum changing the ratio and not affect the mechanical advantage that that lever provides.

Please show your work

With respect to the front weight I still have no idea what you're talking about. I think you are conflating the front weight and the mass of the lead. Of course the lead moves to a different position with a lighter hammer as the FW changes to accommodate the weight of the hammer 🤫. The mass of the lead doesn't change, of course, but its new position changes the MOI of the key lever (by changing the center mass) which changes the MOI of the whole system. The lighter hammer also changes the MOI via the hammer-shank lever assembly. But the effective contribution of each is not equal. The lighter hammer reduces the MOI and the movement of the lead does too. But the contribution of the hammer weight reduction is much greater than the contribution of the slight movement of the lead in terms of MOI. You should be able to do the math if your calculations claims are true.  If not I can refer you to an article on the subject, which I've already done at least once. 

All,

I'll address two fallacies (AR and FW).

Action Ratio is NOT a component of Leverage. Because you can change the leverage and keep the same action ratio. Its just not a reliable measurement for calculating leverage. For calculating leverage accurately, you simply want the actual lengths of the parts.

Front weight. When you slide a weight backwards towards the balance rail, you are reducing the effect of the leveraged mass to manipulate down weight. So as neighboring hammers get lighter a weight gets slid further back instead of being reduced. Plus, another problem with FW is that it accepts the varying weight of the parts themselves That's why the leads often end up in non sequential locations.

Using these two inaccurate means of measurement leads to unpredictable results when different masses and leverages occur from piano to piano. Using inertia as a measurement provides a consistent numbering system that every touch of every piano can conform to.

-chris

------------------------------
Chernobieff Piano Restorations
All the elements are known, and yet no combination there of creates life. Yet we are here.
865-986-7720 (text only please)

Original Message:
Sent: 07-28-2023 14:00
From: David Love
Subject: Key ratio

Let me just add:

Chris wrote:

"When a weight is being slid along a key to match a DW target or a FW target on a scale, it is equivalent to sliding a hammer along the shank to get a SW target."

That is completely and utterly false.  Moving the hammer in on the shank to achieve a SW target changes the output on the hammer/shank assembly lever and with it the overall action ratio.  Sliding a lead along the key to achieve a specific FW target has no effect on the action ratio, zero, zip. That's a very major difference and your comment belies a fundamental understanding of this process. 

Since inertia in the system is largely a function of the AR (leverage) and mass it's trying to move (and where that mass is located), no matter how many leads you put in a key the AR remains unchanged and the relationship between AR and hammers mass remains unchanged.  The added leads required to achieve a certain BW or FW (however you want to think about it) will, to some degree, add to the inertia but the inertia problem that exists in many overleaded keyboards is not because of the excess lead, rather it's the poor relationship between the AR and hammer mass (which we refer to as SW in the Stanwood system) that is responsible for the major part of that.  The excess lead contributes some but pales in comparison to the AR/SW relationship and removing lead will not fix that problem.  Excess leading (or very high FWs) simply tell us that there's a problem.  The only way to fix a high inertia situation is to either lower the AR or lower the SW, or some combination of both. 

In the model I am using one can infer that AR/SW relationship using FW, SW, BW data to see if you have a problem, plus I can tell you what needs to be modified and by how much.  Since most of us don't work with inertia formulas because they don't give us much in terms of practical solutions (how much should I change the SW or AR by to achieve my goal), it's not very useful.  I know some programs, like Gravagne's, give an inertia number but it's of little value other than curiosity for the nerds. (Last I checked Gravagne was also still using "downweight" which doesn't tease out the friction variability and thus is somewhat antiquated.)  That's especially true because the inertia in all pianos graduates from relatively high to relatively low from bottom to top of the scale since the hammers are always decreasing in mass and, generally, the AR is remaining constant, or fairly constant.  Because of that fact the Fandrich/Rhodes system used A4 as their target note for evaluation of the entire action.  Those same formulas (whatever it was that they used) would yield something quite different if a target was chosen higher or lower in the scale and would have to be modified accordingly.

------------------------------
David Love RPT
www.davidlovepianos.com
davidlovepianos@comcast.net
415 407 8320

Original Message:
Sent: 07-28-2023 12:34
From: David Love
Subject: Key ratio

To All

I still don't know what Chris is talking about. It makes no sense. Maybe someone else can explain it to me. There's no equivalence to the examples he gave. It's like asking for further explanation and having the person repeat what they said but louder. 

------------------------------
David Love RPT
www.davidlovepianos.com
davidlovepianos@comcast.net
415 407 8320

Original Message:
Sent: 07-28-2023 09:03
From: Chris Chernobieff
Subject: Key ratio

Its a public forum David, i didn't write it to you specifically in the first place.

I guess i should put "to all" from now on.

To all,

When a weight is being slid along a key to match a DW target or a FW target on a scale, it is equivalent to sliding a hammer along the shank to get a SW target. Both methods are/would be using leverage disadvantageously and at the cost of controlling the mass and inertia.

-chris

------------------------------
Chernobieff Piano Restorations
All the elements are known, and yet no combination there of creates life. Yet we are here.
865-986-7720 (text only please)

Original Message:
Sent: 07-28-2023 01:48
From: David Love
Subject: Key ratio

Chris

I read this 3+ times. I really tried. I even tried altering the 'em-PHA-sis on different syl-LA-bles. I still have no idea what you're talking about. But don't try again on my account, please. 

------------------------------
David Love RPT
www.davidlovepianos.com
davidlovepianos@comcast.net
415 407 8320

Original Message:
Sent: 07-28-2023 01:09
From: Chris Chernobieff
Subject: Key ratio

One problem with using FW as a measure. Lets say you have 10 keys with 2 leads each. because the hammer gets lights you have to slide them backwards so they have less effect. This is an admission a lighter weight would do the same thing.

That's just one way FW screws up inertia. 

Also, saying an action is light, medium, or heavy is not inertia control. Those are ballpark guesses that use terms that are relative. Its equivalent to saying that a weighted wheel will reach the bottom of a hill slowly, in due time, or quickly. Because i use inertia as a direct measure, i can say the weighted wheel will reach the bottom in 10 seconds. With that capability inertia can be communicated to others precisely, duplicated, and the smoothness across the compass controlled unlike what you can do with FW based systems.

-chris

-chris

------------------------------
Chernobieff Piano Restorations
All the elements are known, and yet no combination there of creates life. Yet we are here.
865-986-7720 (text only please)

Original Message:
Sent: 07-24-2023 13:06
From: David Love
Subject: Key ratio

David H

Sounds like a class not to be missed.  My beta testing is more to do with determining optimum hammer weight and then calculating a specific note for note weight curve based on the set you are choosing (rather than a somewhat predetermined "zone") and then the accompanying calculated FW curve to yield a specific BW that you choose.  From those numbers I can tell if you have an inertia problem or not (either too much or not enough).   It achieves that without having to measure action ratios at all, something most techs don't seem that comfortable with plus there's an inconsistency in measurement styles and what certain ARs mean in different methods. 

But once you have those two weight curves then where to place the leads (if you're starting from scratch which most of us aren't) is certainly in interesting topic.  It's been addressed in the past as it relates to key return (the accelerated action) but in spite of that slight benefit it's interesting to note that Steinway abandoned the more leads nearer the balance pin approach in favor of the 3-2-1-0 approach of the past.  

Interesting topic though.  Sorry I can't be there.  

------------------------------
David Love RPT
www.davidlovepianos.com
davidlovepianos@comcast.net
415 407 8320

Original Message:
Sent: 07-23-2023 07:45
From: David Hughes
Subject: Key ratio

Replying to David Love, message #12: I believe the two instructors are Dean Reyburn and some guy named Hughes something.

------------------------------
David Hughes RPT
Vintage Case Parts
Glyndon MD
(443) 522-2201

Original Message:
Sent: 07-23-2023 00:03
From: David Love
Subject: Key ratio

Thanks David. Who are the two instructors?  Not going, unfortunately

------------------------------
David Love RPT
www.davidlovepianos.com
davidlovepianos@comcast.net
415 407 8320

Original Message:
Sent: 07-21-2023 09:28
From: David Hughes
Subject: Key ratio

Everyone involved in this touchweight/key ratio/action ratio/inertia/momentum discussion might enjoy a class next week at our annual convention in Arlington, VA titled "Weigh-Off 101". I understand from the two instructors it will get deeper into these topics than merely a "101" approach, though all the basics will be covered, too. Some eye-opening examples of exactly where the lead can (should?) be placed along the length of the keystick will be included. Oh boy, I'll be in the front row!

David G. Hughes, RPT

Baltimore Chapter 

------------------------------
David Hughes RPT
Vintage Case Parts
Glyndon MD
(443) 522-2201

Original Message:
Sent: 07-18-2023 10:57
From: Dave Conte
Subject: Key ratio

Question about key ratios. I am about to replace the angled capstans on a 95 year old Hamburg Steinway model M grand with straight WNG capstans. I find the straight line drifts 3 mm from the balance hole #1 at 117.5mm to 120.5mm at #88. The balance rail holes are located precisely the same distance from the back of the key at #1 and #88. Key ratio of the naturals from rep center to balance hole is 1:1.89 on #1 and 1:1.94 on #88. Could this be intentional or just a manufacturing error?

------------------------------
Dave Conte, RPT

Piano Technician in Residence
The University of Tennessee
College of Music
Knoxville TN
(817) 307-5656
Owner: Rocky Top Piano
------------------------------

Mr. Love and Mr. Chernobieff,

It sure would have been sparkling (and sparring) to have the two of you present in the Action Weigh-Off 101 class offered by Mr. Reyburn and Mr. Hughes this past week at our national convention. :-)

In this discussion leverage, referring to the mechanical advantage gained by using a lever, or series of levers as you see in a piano, to magnify the force applied to an object and action ratio are used interchangeably.  If you change the AR, the product of those three levers, you necessarily change the mechanical advantage. That's just a physical fact.

Please explain to me how you can change one and not the other. I'll make it simple, let's just talk about the key lever, a simple Teeter-Totter with a 1:1 ratio (fulcrum in the middle). Please show me how you can move the fulcrum changing the ratio and not affect the mechanical advantage that that lever provides.

Please show your work

With respect to the front weight I still have no idea what you're talking about. I think you are conflating the front weight and the mass of the lead. Of course the lead moves to a different position with a lighter hammer as the FW changes to accommodate the weight of the hammer 🤫. The mass of the lead doesn't change, of course, but its new position changes the MOI of the key lever (by changing the center mass) which changes the MOI of the whole system. The lighter hammer also changes the MOI via the hammer-shank lever assembly. But the effective contribution of each is not equal. The lighter hammer reduces the MOI and the movement of the lead does too. But the contribution of the hammer weight reduction is much greater than the contribution of the slight movement of the lead in terms of MOI. You should be able to do the math if your calculations claims are true.  If not I can refer you to an article on the subject, which I've already done at least once. 

All,

I'll address two fallacies (AR and FW).

Action Ratio is NOT a component of Leverage. Because you can change the leverage and keep the same action ratio. Its just not a reliable measurement for calculating leverage. For calculating leverage accurately, you simply want the actual lengths of the parts.

Front weight. When you slide a weight backwards towards the balance rail, you are reducing the effect of the leveraged mass to manipulate down weight. So as neighboring hammers get lighter a weight gets slid further back instead of being reduced. Plus, another problem with FW is that it accepts the varying weight of the parts themselves That's why the leads often end up in non sequential locations.

Using these two inaccurate means of measurement leads to unpredictable results when different masses and leverages occur from piano to piano. Using inertia as a measurement provides a consistent numbering system that every touch of every piano can conform to.

-chris

------------------------------
Chernobieff Piano Restorations
All the elements are known, and yet no combination there of creates life. Yet we are here.
865-986-7720 (text only please)

Original Message:
Sent: 07-28-2023 14:00
From: David Love
Subject: Key ratio

Let me just add:

Chris wrote:

"When a weight is being slid along a key to match a DW target or a FW target on a scale, it is equivalent to sliding a hammer along the shank to get a SW target."

That is completely and utterly false.  Moving the hammer in on the shank to achieve a SW target changes the output on the hammer/shank assembly lever and with it the overall action ratio.  Sliding a lead along the key to achieve a specific FW target has no effect on the action ratio, zero, zip. That's a very major difference and your comment belies a fundamental understanding of this process. 

Since inertia in the system is largely a function of the AR (leverage) and mass it's trying to move (and where that mass is located), no matter how many leads you put in a key the AR remains unchanged and the relationship between AR and hammers mass remains unchanged.  The added leads required to achieve a certain BW or FW (however you want to think about it) will, to some degree, add to the inertia but the inertia problem that exists in many overleaded keyboards is not because of the excess lead, rather it's the poor relationship between the AR and hammer mass (which we refer to as SW in the Stanwood system) that is responsible for the major part of that.  The excess lead contributes some but pales in comparison to the AR/SW relationship and removing lead will not fix that problem.  Excess leading (or very high FWs) simply tell us that there's a problem.  The only way to fix a high inertia situation is to either lower the AR or lower the SW, or some combination of both. 

In the model I am using one can infer that AR/SW relationship using FW, SW, BW data to see if you have a problem, plus I can tell you what needs to be modified and by how much.  Since most of us don't work with inertia formulas because they don't give us much in terms of practical solutions (how much should I change the SW or AR by to achieve my goal), it's not very useful.  I know some programs, like Gravagne's, give an inertia number but it's of little value other than curiosity for the nerds. (Last I checked Gravagne was also still using "downweight" which doesn't tease out the friction variability and thus is somewhat antiquated.)  That's especially true because the inertia in all pianos graduates from relatively high to relatively low from bottom to top of the scale since the hammers are always decreasing in mass and, generally, the AR is remaining constant, or fairly constant.  Because of that fact the Fandrich/Rhodes system used A4 as their target note for evaluation of the entire action.  Those same formulas (whatever it was that they used) would yield something quite different if a target was chosen higher or lower in the scale and would have to be modified accordingly.

------------------------------
David Love RPT
www.davidlovepianos.com
davidlovepianos@comcast.net
415 407 8320

Original Message:
Sent: 07-28-2023 12:34
From: David Love
Subject: Key ratio

To All

I still don't know what Chris is talking about. It makes no sense. Maybe someone else can explain it to me. There's no equivalence to the examples he gave. It's like asking for further explanation and having the person repeat what they said but louder. 

------------------------------
David Love RPT
www.davidlovepianos.com
davidlovepianos@comcast.net
415 407 8320

Original Message:
Sent: 07-28-2023 09:03
From: Chris Chernobieff
Subject: Key ratio

Its a public forum David, i didn't write it to you specifically in the first place.

I guess i should put "to all" from now on.

To all,

When a weight is being slid along a key to match a DW target or a FW target on a scale, it is equivalent to sliding a hammer along the shank to get a SW target. Both methods are/would be using leverage disadvantageously and at the cost of controlling the mass and inertia.

-chris

------------------------------
Chernobieff Piano Restorations
All the elements are known, and yet no combination there of creates life. Yet we are here.
865-986-7720 (text only please)

Original Message:
Sent: 07-28-2023 01:48
From: David Love
Subject: Key ratio

Chris

I read this 3+ times. I really tried. I even tried altering the 'em-PHA-sis on different syl-LA-bles. I still have no idea what you're talking about. But don't try again on my account, please. 

------------------------------
David Love RPT
www.davidlovepianos.com
davidlovepianos@comcast.net
415 407 8320

Original Message:
Sent: 07-28-2023 01:09
From: Chris Chernobieff
Subject: Key ratio

One problem with using FW as a measure. Lets say you have 10 keys with 2 leads each. because the hammer gets lights you have to slide them backwards so they have less effect. This is an admission a lighter weight would do the same thing.

That's just one way FW screws up inertia. 

Also, saying an action is light, medium, or heavy is not inertia control. Those are ballpark guesses that use terms that are relative. Its equivalent to saying that a weighted wheel will reach the bottom of a hill slowly, in due time, or quickly. Because i use inertia as a direct measure, i can say the weighted wheel will reach the bottom in 10 seconds. With that capability inertia can be communicated to others precisely, duplicated, and the smoothness across the compass controlled unlike what you can do with FW based systems.

-chris

-chris

------------------------------
Chernobieff Piano Restorations
All the elements are known, and yet no combination there of creates life. Yet we are here.
865-986-7720 (text only please)

Original Message:
Sent: 07-24-2023 13:06
From: David Love
Subject: Key ratio

David H

Sounds like a class not to be missed.  My beta testing is more to do with determining optimum hammer weight and then calculating a specific note for note weight curve based on the set you are choosing (rather than a somewhat predetermined "zone") and then the accompanying calculated FW curve to yield a specific BW that you choose.  From those numbers I can tell if you have an inertia problem or not (either too much or not enough).   It achieves that without having to measure action ratios at all, something most techs don't seem that comfortable with plus there's an inconsistency in measurement styles and what certain ARs mean in different methods. 

But once you have those two weight curves then where to place the leads (if you're starting from scratch which most of us aren't) is certainly in interesting topic.  It's been addressed in the past as it relates to key return (the accelerated action) but in spite of that slight benefit it's interesting to note that Steinway abandoned the more leads nearer the balance pin approach in favor of the 3-2-1-0 approach of the past.  

Interesting topic though.  Sorry I can't be there.  

------------------------------
David Love RPT
www.davidlovepianos.com
davidlovepianos@comcast.net
415 407 8320

Original Message:
Sent: 07-23-2023 07:45
From: David Hughes
Subject: Key ratio

Replying to David Love, message #12: I believe the two instructors are Dean Reyburn and some guy named Hughes something.

------------------------------
David Hughes RPT
Vintage Case Parts
Glyndon MD
(443) 522-2201

Original Message:
Sent: 07-23-2023 00:03
From: David Love
Subject: Key ratio

Thanks David. Who are the two instructors?  Not going, unfortunately

------------------------------
David Love RPT
www.davidlovepianos.com
davidlovepianos@comcast.net
415 407 8320

Original Message:
Sent: 07-21-2023 09:28
From: David Hughes
Subject: Key ratio

Everyone involved in this touchweight/key ratio/action ratio/inertia/momentum discussion might enjoy a class next week at our annual convention in Arlington, VA titled "Weigh-Off 101". I understand from the two instructors it will get deeper into these topics than merely a "101" approach, though all the basics will be covered, too. Some eye-opening examples of exactly where the lead can (should?) be placed along the length of the keystick will be included. Oh boy, I'll be in the front row!

David G. Hughes, RPT

Baltimore Chapter 

------------------------------
David Hughes RPT
Vintage Case Parts
Glyndon MD
(443) 522-2201

Original Message:
Sent: 07-18-2023 10:57
From: Dave Conte
Subject: Key ratio

Question about key ratios. I am about to replace the angled capstans on a 95 year old Hamburg Steinway model M grand with straight WNG capstans. I find the straight line drifts 3 mm from the balance hole #1 at 117.5mm to 120.5mm at #88. The balance rail holes are located precisely the same distance from the back of the key at #1 and #88. Key ratio of the naturals from rep center to balance hole is 1:1.89 on #1 and 1:1.94 on #88. Could this be intentional or just a manufacturing error?

------------------------------
Dave Conte, RPT

Piano Technician in Residence
The University of Tennessee
College of Music
Knoxville TN
(817) 307-5656
Owner: Rocky Top Piano
------------------------------

I attended the class to which Mr. Hughes refers, and wholeheartedly agree with his suggestion.

Peace,

Alan 

Mr. Love and Mr. Chernobieff,

It sure would have been sparkling (and sparring) to have the two of you present in the Action Weigh-Off 101 class offered by Mr. Reyburn and Mr. Hughes this past week at our national convention. :-)

In this discussion leverage, referring to the mechanical advantage gained by using a lever, or series of levers as you see in a piano, to magnify the force applied to an object and action ratio are used interchangeably.  If you change the AR, the product of those three levers, you necessarily change the mechanical advantage. That's just a physical fact.

Please explain to me how you can change one and not the other. I'll make it simple, let's just talk about the key lever, a simple Teeter-Totter with a 1:1 ratio (fulcrum in the middle). Please show me how you can move the fulcrum changing the ratio and not affect the mechanical advantage that that lever provides.

Please show your work

With respect to the front weight I still have no idea what you're talking about. I think you are conflating the front weight and the mass of the lead. Of course the lead moves to a different position with a lighter hammer as the FW changes to accommodate the weight of the hammer 🤫. The mass of the lead doesn't change, of course, but its new position changes the MOI of the key lever (by changing the center mass) which changes the MOI of the whole system. The lighter hammer also changes the MOI via the hammer-shank lever assembly. But the effective contribution of each is not equal. The lighter hammer reduces the MOI and the movement of the lead does too. But the contribution of the hammer weight reduction is much greater than the contribution of the slight movement of the lead in terms of MOI. You should be able to do the math if your calculations claims are true.  If not I can refer you to an article on the subject, which I've already done at least once. 

All,

I'll address two fallacies (AR and FW).

Action Ratio is NOT a component of Leverage. Because you can change the leverage and keep the same action ratio. Its just not a reliable measurement for calculating leverage. For calculating leverage accurately, you simply want the actual lengths of the parts.

Front weight. When you slide a weight backwards towards the balance rail, you are reducing the effect of the leveraged mass to manipulate down weight. So as neighboring hammers get lighter a weight gets slid further back instead of being reduced. Plus, another problem with FW is that it accepts the varying weight of the parts themselves That's why the leads often end up in non sequential locations.

Using these two inaccurate means of measurement leads to unpredictable results when different masses and leverages occur from piano to piano. Using inertia as a measurement provides a consistent numbering system that every touch of every piano can conform to.

-chris

------------------------------
Chernobieff Piano Restorations
All the elements are known, and yet no combination there of creates life. Yet we are here.
865-986-7720 (text only please)

Original Message:
Sent: 07-28-2023 14:00
From: David Love
Subject: Key ratio

Let me just add:

Chris wrote:

"When a weight is being slid along a key to match a DW target or a FW target on a scale, it is equivalent to sliding a hammer along the shank to get a SW target."

That is completely and utterly false.  Moving the hammer in on the shank to achieve a SW target changes the output on the hammer/shank assembly lever and with it the overall action ratio.  Sliding a lead along the key to achieve a specific FW target has no effect on the action ratio, zero, zip. That's a very major difference and your comment belies a fundamental understanding of this process. 

Since inertia in the system is largely a function of the AR (leverage) and mass it's trying to move (and where that mass is located), no matter how many leads you put in a key the AR remains unchanged and the relationship between AR and hammers mass remains unchanged.  The added leads required to achieve a certain BW or FW (however you want to think about it) will, to some degree, add to the inertia but the inertia problem that exists in many overleaded keyboards is not because of the excess lead, rather it's the poor relationship between the AR and hammer mass (which we refer to as SW in the Stanwood system) that is responsible for the major part of that.  The excess lead contributes some but pales in comparison to the AR/SW relationship and removing lead will not fix that problem.  Excess leading (or very high FWs) simply tell us that there's a problem.  The only way to fix a high inertia situation is to either lower the AR or lower the SW, or some combination of both. 

In the model I am using one can infer that AR/SW relationship using FW, SW, BW data to see if you have a problem, plus I can tell you what needs to be modified and by how much.  Since most of us don't work with inertia formulas because they don't give us much in terms of practical solutions (how much should I change the SW or AR by to achieve my goal), it's not very useful.  I know some programs, like Gravagne's, give an inertia number but it's of little value other than curiosity for the nerds. (Last I checked Gravagne was also still using "downweight" which doesn't tease out the friction variability and thus is somewhat antiquated.)  That's especially true because the inertia in all pianos graduates from relatively high to relatively low from bottom to top of the scale since the hammers are always decreasing in mass and, generally, the AR is remaining constant, or fairly constant.  Because of that fact the Fandrich/Rhodes system used A4 as their target note for evaluation of the entire action.  Those same formulas (whatever it was that they used) would yield something quite different if a target was chosen higher or lower in the scale and would have to be modified accordingly.

------------------------------
David Love RPT
www.davidlovepianos.com
davidlovepianos@comcast.net
415 407 8320

Original Message:
Sent: 07-28-2023 12:34
From: David Love
Subject: Key ratio

To All

I still don't know what Chris is talking about. It makes no sense. Maybe someone else can explain it to me. There's no equivalence to the examples he gave. It's like asking for further explanation and having the person repeat what they said but louder. 

------------------------------
David Love RPT
www.davidlovepianos.com
davidlovepianos@comcast.net
415 407 8320

Original Message:
Sent: 07-28-2023 09:03
From: Chris Chernobieff
Subject: Key ratio

Its a public forum David, i didn't write it to you specifically in the first place.

I guess i should put "to all" from now on.

To all,

When a weight is being slid along a key to match a DW target or a FW target on a scale, it is equivalent to sliding a hammer along the shank to get a SW target. Both methods are/would be using leverage disadvantageously and at the cost of controlling the mass and inertia.

-chris

------------------------------
Chernobieff Piano Restorations
All the elements are known, and yet no combination there of creates life. Yet we are here.
865-986-7720 (text only please)

Original Message:
Sent: 07-28-2023 01:48
From: David Love
Subject: Key ratio

Chris

I read this 3+ times. I really tried. I even tried altering the 'em-PHA-sis on different syl-LA-bles. I still have no idea what you're talking about. But don't try again on my account, please. 

------------------------------
David Love RPT
www.davidlovepianos.com
davidlovepianos@comcast.net
415 407 8320

Original Message:
Sent: 07-28-2023 01:09
From: Chris Chernobieff
Subject: Key ratio

One problem with using FW as a measure. Lets say you have 10 keys with 2 leads each. because the hammer gets lights you have to slide them backwards so they have less effect. This is an admission a lighter weight would do the same thing.

That's just one way FW screws up inertia. 

Also, saying an action is light, medium, or heavy is not inertia control. Those are ballpark guesses that use terms that are relative. Its equivalent to saying that a weighted wheel will reach the bottom of a hill slowly, in due time, or quickly. Because i use inertia as a direct measure, i can say the weighted wheel will reach the bottom in 10 seconds. With that capability inertia can be communicated to others precisely, duplicated, and the smoothness across the compass controlled unlike what you can do with FW based systems.

-chris

-chris

------------------------------
Chernobieff Piano Restorations
All the elements are known, and yet no combination there of creates life. Yet we are here.
865-986-7720 (text only please)

Original Message:
Sent: 07-24-2023 13:06
From: David Love
Subject: Key ratio

David H

Sounds like a class not to be missed.  My beta testing is more to do with determining optimum hammer weight and then calculating a specific note for note weight curve based on the set you are choosing (rather than a somewhat predetermined "zone") and then the accompanying calculated FW curve to yield a specific BW that you choose.  From those numbers I can tell if you have an inertia problem or not (either too much or not enough).   It achieves that without having to measure action ratios at all, something most techs don't seem that comfortable with plus there's an inconsistency in measurement styles and what certain ARs mean in different methods. 

But once you have those two weight curves then where to place the leads (if you're starting from scratch which most of us aren't) is certainly in interesting topic.  It's been addressed in the past as it relates to key return (the accelerated action) but in spite of that slight benefit it's interesting to note that Steinway abandoned the more leads nearer the balance pin approach in favor of the 3-2-1-0 approach of the past.  

Interesting topic though.  Sorry I can't be there.  

------------------------------
David Love RPT
www.davidlovepianos.com
davidlovepianos@comcast.net
415 407 8320

Original Message:
Sent: 07-23-2023 07:45
From: David Hughes
Subject: Key ratio

Replying to David Love, message #12: I believe the two instructors are Dean Reyburn and some guy named Hughes something.

------------------------------
David Hughes RPT
Vintage Case Parts
Glyndon MD
(443) 522-2201

Original Message:
Sent: 07-23-2023 00:03
From: David Love
Subject: Key ratio

Thanks David. Who are the two instructors?  Not going, unfortunately

------------------------------
David Love RPT
www.davidlovepianos.com
davidlovepianos@comcast.net
415 407 8320

Original Message:
Sent: 07-21-2023 09:28
From: David Hughes
Subject: Key ratio

Everyone involved in this touchweight/key ratio/action ratio/inertia/momentum discussion might enjoy a class next week at our annual convention in Arlington, VA titled "Weigh-Off 101". I understand from the two instructors it will get deeper into these topics than merely a "101" approach, though all the basics will be covered, too. Some eye-opening examples of exactly where the lead can (should?) be placed along the length of the keystick will be included. Oh boy, I'll be in the front row!

David G. Hughes, RPT

Baltimore Chapter 

------------------------------
David Hughes RPT
Vintage Case Parts
Glyndon MD
(443) 522-2201

Original Message:
Sent: 07-18-2023 10:57
From: Dave Conte
Subject: Key ratio

Question about key ratios. I am about to replace the angled capstans on a 95 year old Hamburg Steinway model M grand with straight WNG capstans. I find the straight line drifts 3 mm from the balance hole #1 at 117.5mm to 120.5mm at #88. The balance rail holes are located precisely the same distance from the back of the key at #1 and #88. Key ratio of the naturals from rep center to balance hole is 1:1.89 on #1 and 1:1.94 on #88. Could this be intentional or just a manufacturing error?

------------------------------
Dave Conte, RPT

Piano Technician in Residence
The University of Tennessee
College of Music
Knoxville TN
(817) 307-5656
Owner: Rocky Top Piano
------------------------------

Suggest this as a round table to the convention team for next year.

I attended the class to which Mr. Hughes refers, and wholeheartedly agree with his suggestion.

Peace,

Alan 

Mr. Love and Mr. Chernobieff,

It sure would have been sparkling (and sparring) to have the two of you present in the Action Weigh-Off 101 class offered by Mr. Reyburn and Mr. Hughes this past week at our national convention. :-)

In this discussion leverage, referring to the mechanical advantage gained by using a lever, or series of levers as you see in a piano, to magnify the force applied to an object and action ratio are used interchangeably.  If you change the AR, the product of those three levers, you necessarily change the mechanical advantage. That's just a physical fact.

Please explain to me how you can change one and not the other. I'll make it simple, let's just talk about the key lever, a simple Teeter-Totter with a 1:1 ratio (fulcrum in the middle). Please show me how you can move the fulcrum changing the ratio and not affect the mechanical advantage that that lever provides.

Please show your work

With respect to the front weight I still have no idea what you're talking about. I think you are conflating the front weight and the mass of the lead. Of course the lead moves to a different position with a lighter hammer as the FW changes to accommodate the weight of the hammer 🤫. The mass of the lead doesn't change, of course, but its new position changes the MOI of the key lever (by changing the center mass) which changes the MOI of the whole system. The lighter hammer also changes the MOI via the hammer-shank lever assembly. But the effective contribution of each is not equal. The lighter hammer reduces the MOI and the movement of the lead does too. But the contribution of the hammer weight reduction is much greater than the contribution of the slight movement of the lead in terms of MOI. You should be able to do the math if your calculations claims are true.  If not I can refer you to an article on the subject, which I've already done at least once. 

All,

I'll address two fallacies (AR and FW).

Action Ratio is NOT a component of Leverage. Because you can change the leverage and keep the same action ratio. Its just not a reliable measurement for calculating leverage. For calculating leverage accurately, you simply want the actual lengths of the parts.

Front weight. When you slide a weight backwards towards the balance rail, you are reducing the effect of the leveraged mass to manipulate down weight. So as neighboring hammers get lighter a weight gets slid further back instead of being reduced. Plus, another problem with FW is that it accepts the varying weight of the parts themselves That's why the leads often end up in non sequential locations.

Using these two inaccurate means of measurement leads to unpredictable results when different masses and leverages occur from piano to piano. Using inertia as a measurement provides a consistent numbering system that every touch of every piano can conform to.

-chris

------------------------------
Chernobieff Piano Restorations
All the elements are known, and yet no combination there of creates life. Yet we are here.
865-986-7720 (text only please)

Original Message:
Sent: 07-28-2023 14:00
From: David Love
Subject: Key ratio

Let me just add:

Chris wrote:

"When a weight is being slid along a key to match a DW target or a FW target on a scale, it is equivalent to sliding a hammer along the shank to get a SW target."

That is completely and utterly false.  Moving the hammer in on the shank to achieve a SW target changes the output on the hammer/shank assembly lever and with it the overall action ratio.  Sliding a lead along the key to achieve a specific FW target has no effect on the action ratio, zero, zip. That's a very major difference and your comment belies a fundamental understanding of this process. 

Since inertia in the system is largely a function of the AR (leverage) and mass it's trying to move (and where that mass is located), no matter how many leads you put in a key the AR remains unchanged and the relationship between AR and hammers mass remains unchanged.  The added leads required to achieve a certain BW or FW (however you want to think about it) will, to some degree, add to the inertia but the inertia problem that exists in many overleaded keyboards is not because of the excess lead, rather it's the poor relationship between the AR and hammer mass (which we refer to as SW in the Stanwood system) that is responsible for the major part of that.  The excess lead contributes some but pales in comparison to the AR/SW relationship and removing lead will not fix that problem.  Excess leading (or very high FWs) simply tell us that there's a problem.  The only way to fix a high inertia situation is to either lower the AR or lower the SW, or some combination of both. 

In the model I am using one can infer that AR/SW relationship using FW, SW, BW data to see if you have a problem, plus I can tell you what needs to be modified and by how much.  Since most of us don't work with inertia formulas because they don't give us much in terms of practical solutions (how much should I change the SW or AR by to achieve my goal), it's not very useful.  I know some programs, like Gravagne's, give an inertia number but it's of little value other than curiosity for the nerds. (Last I checked Gravagne was also still using "downweight" which doesn't tease out the friction variability and thus is somewhat antiquated.)  That's especially true because the inertia in all pianos graduates from relatively high to relatively low from bottom to top of the scale since the hammers are always decreasing in mass and, generally, the AR is remaining constant, or fairly constant.  Because of that fact the Fandrich/Rhodes system used A4 as their target note for evaluation of the entire action.  Those same formulas (whatever it was that they used) would yield something quite different if a target was chosen higher or lower in the scale and would have to be modified accordingly.

------------------------------
David Love RPT
www.davidlovepianos.com
davidlovepianos@comcast.net
415 407 8320

Original Message:
Sent: 07-28-2023 12:34
From: David Love
Subject: Key ratio

To All

I still don't know what Chris is talking about. It makes no sense. Maybe someone else can explain it to me. There's no equivalence to the examples he gave. It's like asking for further explanation and having the person repeat what they said but louder. 

------------------------------
David Love RPT
www.davidlovepianos.com
davidlovepianos@comcast.net
415 407 8320

Original Message:
Sent: 07-28-2023 09:03
From: Chris Chernobieff
Subject: Key ratio

Its a public forum David, i didn't write it to you specifically in the first place.

I guess i should put "to all" from now on.

To all,

When a weight is being slid along a key to match a DW target or a FW target on a scale, it is equivalent to sliding a hammer along the shank to get a SW target. Both methods are/would be using leverage disadvantageously and at the cost of controlling the mass and inertia.

-chris

------------------------------
Chernobieff Piano Restorations
All the elements are known, and yet no combination there of creates life. Yet we are here.
865-986-7720 (text only please)

Original Message:
Sent: 07-28-2023 01:48
From: David Love
Subject: Key ratio

Chris

I read this 3+ times. I really tried. I even tried altering the 'em-PHA-sis on different syl-LA-bles. I still have no idea what you're talking about. But don't try again on my account, please. 

------------------------------
David Love RPT
www.davidlovepianos.com
davidlovepianos@comcast.net
415 407 8320

Original Message:
Sent: 07-28-2023 01:09
From: Chris Chernobieff
Subject: Key ratio

One problem with using FW as a measure. Lets say you have 10 keys with 2 leads each. because the hammer gets lights you have to slide them backwards so they have less effect. This is an admission a lighter weight would do the same thing.

That's just one way FW screws up inertia. 

Also, saying an action is light, medium, or heavy is not inertia control. Those are ballpark guesses that use terms that are relative. Its equivalent to saying that a weighted wheel will reach the bottom of a hill slowly, in due time, or quickly. Because i use inertia as a direct measure, i can say the weighted wheel will reach the bottom in 10 seconds. With that capability inertia can be communicated to others precisely, duplicated, and the smoothness across the compass controlled unlike what you can do with FW based systems.

-chris

-chris

------------------------------
Chernobieff Piano Restorations
All the elements are known, and yet no combination there of creates life. Yet we are here.
865-986-7720 (text only please)

Original Message:
Sent: 07-24-2023 13:06
From: David Love
Subject: Key ratio

David H

Sounds like a class not to be missed.  My beta testing is more to do with determining optimum hammer weight and then calculating a specific note for note weight curve based on the set you are choosing (rather than a somewhat predetermined "zone") and then the accompanying calculated FW curve to yield a specific BW that you choose.  From those numbers I can tell if you have an inertia problem or not (either too much or not enough).   It achieves that without having to measure action ratios at all, something most techs don't seem that comfortable with plus there's an inconsistency in measurement styles and what certain ARs mean in different methods. 

But once you have those two weight curves then where to place the leads (if you're starting from scratch which most of us aren't) is certainly in interesting topic.  It's been addressed in the past as it relates to key return (the accelerated action) but in spite of that slight benefit it's interesting to note that Steinway abandoned the more leads nearer the balance pin approach in favor of the 3-2-1-0 approach of the past.  

Interesting topic though.  Sorry I can't be there.  

------------------------------
David Love RPT
www.davidlovepianos.com
davidlovepianos@comcast.net
415 407 8320

Original Message:
Sent: 07-23-2023 07:45
From: David Hughes
Subject: Key ratio

Replying to David Love, message #12: I believe the two instructors are Dean Reyburn and some guy named Hughes something.

------------------------------
David Hughes RPT
Vintage Case Parts
Glyndon MD
(443) 522-2201

Original Message:
Sent: 07-23-2023 00:03
From: David Love
Subject: Key ratio

Thanks David. Who are the two instructors?  Not going, unfortunately

------------------------------
David Love RPT
www.davidlovepianos.com
davidlovepianos@comcast.net
415 407 8320

Original Message:
Sent: 07-21-2023 09:28
From: David Hughes
Subject: Key ratio

Everyone involved in this touchweight/key ratio/action ratio/inertia/momentum discussion might enjoy a class next week at our annual convention in Arlington, VA titled "Weigh-Off 101". I understand from the two instructors it will get deeper into these topics than merely a "101" approach, though all the basics will be covered, too. Some eye-opening examples of exactly where the lead can (should?) be placed along the length of the keystick will be included. Oh boy, I'll be in the front row!

David G. Hughes, RPT

Baltimore Chapter 

------------------------------
David Hughes RPT
Vintage Case Parts
Glyndon MD
(443) 522-2201

Original Message:
Sent: 07-18-2023 10:57
From: Dave Conte
Subject: Key ratio

Question about key ratios. I am about to replace the angled capstans on a 95 year old Hamburg Steinway model M grand with straight WNG capstans. I find the straight line drifts 3 mm from the balance hole #1 at 117.5mm to 120.5mm at #88. The balance rail holes are located precisely the same distance from the back of the key at #1 and #88. Key ratio of the naturals from rep center to balance hole is 1:1.89 on #1 and 1:1.94 on #88. Could this be intentional or just a manufacturing error?

------------------------------
Dave Conte, RPT

Piano Technician in Residence
The University of Tennessee
College of Music
Knoxville TN
(817) 307-5656
Owner: Rocky Top Piano
------------------------------

Mr. Love and Mr. Chernobieff,

It sure would have been sparkling (and sparring) to have the two of you present in the Action Weigh-Off 101 class offered by Mr. Reyburn and Mr. Hughes this past week at our national convention. :-)

In this discussion leverage, referring to the mechanical advantage gained by using a lever, or series of levers as you see in a piano, to magnify the force applied to an object and action ratio are used interchangeably.  If you change the AR, the product of those three levers, you necessarily change the mechanical advantage. That's just a physical fact.

Please explain to me how you can change one and not the other. I'll make it simple, let's just talk about the key lever, a simple Teeter-Totter with a 1:1 ratio (fulcrum in the middle). Please show me how you can move the fulcrum changing the ratio and not affect the mechanical advantage that that lever provides.

Please show your work

With respect to the front weight I still have no idea what you're talking about. I think you are conflating the front weight and the mass of the lead. Of course the lead moves to a different position with a lighter hammer as the FW changes to accommodate the weight of the hammer 🤫. The mass of the lead doesn't change, of course, but its new position changes the MOI of the key lever (by changing the center mass) which changes the MOI of the whole system. The lighter hammer also changes the MOI via the hammer-shank lever assembly. But the effective contribution of each is not equal. The lighter hammer reduces the MOI and the movement of the lead does too. But the contribution of the hammer weight reduction is much greater than the contribution of the slight movement of the lead in terms of MOI. You should be able to do the math if your calculations claims are true.  If not I can refer you to an article on the subject, which I've already done at least once. 

All,

I'll address two fallacies (AR and FW).

Action Ratio is NOT a component of Leverage. Because you can change the leverage and keep the same action ratio. Its just not a reliable measurement for calculating leverage. For calculating leverage accurately, you simply want the actual lengths of the parts.

Front weight. When you slide a weight backwards towards the balance rail, you are reducing the effect of the leveraged mass to manipulate down weight. So as neighboring hammers get lighter a weight gets slid further back instead of being reduced. Plus, another problem with FW is that it accepts the varying weight of the parts themselves That's why the leads often end up in non sequential locations.

Using these two inaccurate means of measurement leads to unpredictable results when different masses and leverages occur from piano to piano. Using inertia as a measurement provides a consistent numbering system that every touch of every piano can conform to.

-chris

------------------------------
Chernobieff Piano Restorations
All the elements are known, and yet no combination there of creates life. Yet we are here.
865-986-7720 (text only please)

Original Message:
Sent: 07-28-2023 14:00
From: David Love
Subject: Key ratio

Let me just add:

Chris wrote:

"When a weight is being slid along a key to match a DW target or a FW target on a scale, it is equivalent to sliding a hammer along the shank to get a SW target."

That is completely and utterly false.  Moving the hammer in on the shank to achieve a SW target changes the output on the hammer/shank assembly lever and with it the overall action ratio.  Sliding a lead along the key to achieve a specific FW target has no effect on the action ratio, zero, zip. That's a very major difference and your comment belies a fundamental understanding of this process. 

Since inertia in the system is largely a function of the AR (leverage) and mass it's trying to move (and where that mass is located), no matter how many leads you put in a key the AR remains unchanged and the relationship between AR and hammers mass remains unchanged.  The added leads required to achieve a certain BW or FW (however you want to think about it) will, to some degree, add to the inertia but the inertia problem that exists in many overleaded keyboards is not because of the excess lead, rather it's the poor relationship between the AR and hammer mass (which we refer to as SW in the Stanwood system) that is responsible for the major part of that.  The excess lead contributes some but pales in comparison to the AR/SW relationship and removing lead will not fix that problem.  Excess leading (or very high FWs) simply tell us that there's a problem.  The only way to fix a high inertia situation is to either lower the AR or lower the SW, or some combination of both. 

In the model I am using one can infer that AR/SW relationship using FW, SW, BW data to see if you have a problem, plus I can tell you what needs to be modified and by how much.  Since most of us don't work with inertia formulas because they don't give us much in terms of practical solutions (how much should I change the SW or AR by to achieve my goal), it's not very useful.  I know some programs, like Gravagne's, give an inertia number but it's of little value other than curiosity for the nerds. (Last I checked Gravagne was also still using "downweight" which doesn't tease out the friction variability and thus is somewhat antiquated.)  That's especially true because the inertia in all pianos graduates from relatively high to relatively low from bottom to top of the scale since the hammers are always decreasing in mass and, generally, the AR is remaining constant, or fairly constant.  Because of that fact the Fandrich/Rhodes system used A4 as their target note for evaluation of the entire action.  Those same formulas (whatever it was that they used) would yield something quite different if a target was chosen higher or lower in the scale and would have to be modified accordingly.

------------------------------
David Love RPT
www.davidlovepianos.com
davidlovepianos@comcast.net
415 407 8320

Original Message:
Sent: 07-28-2023 12:34
From: David Love
Subject: Key ratio

To All

I still don't know what Chris is talking about. It makes no sense. Maybe someone else can explain it to me. There's no equivalence to the examples he gave. It's like asking for further explanation and having the person repeat what they said but louder. 

------------------------------
David Love RPT
www.davidlovepianos.com
davidlovepianos@comcast.net
415 407 8320

Original Message:
Sent: 07-28-2023 09:03
From: Chris Chernobieff
Subject: Key ratio

Its a public forum David, i didn't write it to you specifically in the first place.

I guess i should put "to all" from now on.

To all,

When a weight is being slid along a key to match a DW target or a FW target on a scale, it is equivalent to sliding a hammer along the shank to get a SW target. Both methods are/would be using leverage disadvantageously and at the cost of controlling the mass and inertia.

-chris

------------------------------
Chernobieff Piano Restorations
All the elements are known, and yet no combination there of creates life. Yet we are here.
865-986-7720 (text only please)

Original Message:
Sent: 07-28-2023 01:48
From: David Love
Subject: Key ratio

Chris

I read this 3+ times. I really tried. I even tried altering the 'em-PHA-sis on different syl-LA-bles. I still have no idea what you're talking about. But don't try again on my account, please. 

------------------------------
David Love RPT
www.davidlovepianos.com
davidlovepianos@comcast.net
415 407 8320

Original Message:
Sent: 07-28-2023 01:09
From: Chris Chernobieff
Subject: Key ratio

One problem with using FW as a measure. Lets say you have 10 keys with 2 leads each. because the hammer gets lights you have to slide them backwards so they have less effect. This is an admission a lighter weight would do the same thing.

That's just one way FW screws up inertia. 

Also, saying an action is light, medium, or heavy is not inertia control. Those are ballpark guesses that use terms that are relative. Its equivalent to saying that a weighted wheel will reach the bottom of a hill slowly, in due time, or quickly. Because i use inertia as a direct measure, i can say the weighted wheel will reach the bottom in 10 seconds. With that capability inertia can be communicated to others precisely, duplicated, and the smoothness across the compass controlled unlike what you can do with FW based systems.

-chris

-chris

------------------------------
Chernobieff Piano Restorations
All the elements are known, and yet no combination there of creates life. Yet we are here.
865-986-7720 (text only please)

Original Message:
Sent: 07-24-2023 13:06
From: David Love
Subject: Key ratio

David H

Sounds like a class not to be missed.  My beta testing is more to do with determining optimum hammer weight and then calculating a specific note for note weight curve based on the set you are choosing (rather than a somewhat predetermined "zone") and then the accompanying calculated FW curve to yield a specific BW that you choose.  From those numbers I can tell if you have an inertia problem or not (either too much or not enough).   It achieves that without having to measure action ratios at all, something most techs don't seem that comfortable with plus there's an inconsistency in measurement styles and what certain ARs mean in different methods. 

But once you have those two weight curves then where to place the leads (if you're starting from scratch which most of us aren't) is certainly in interesting topic.  It's been addressed in the past as it relates to key return (the accelerated action) but in spite of that slight benefit it's interesting to note that Steinway abandoned the more leads nearer the balance pin approach in favor of the 3-2-1-0 approach of the past.  

Interesting topic though.  Sorry I can't be there.  

------------------------------
David Love RPT
www.davidlovepianos.com
davidlovepianos@comcast.net
415 407 8320

Original Message:
Sent: 07-23-2023 07:45
From: David Hughes
Subject: Key ratio

Replying to David Love, message #12: I believe the two instructors are Dean Reyburn and some guy named Hughes something.

------------------------------
David Hughes RPT
Vintage Case Parts
Glyndon MD
(443) 522-2201

Original Message:
Sent: 07-23-2023 00:03
From: David Love
Subject: Key ratio

Thanks David. Who are the two instructors?  Not going, unfortunately

------------------------------
David Love RPT
www.davidlovepianos.com
davidlovepianos@comcast.net
415 407 8320

Original Message:
Sent: 07-21-2023 09:28
From: David Hughes
Subject: Key ratio

Everyone involved in this touchweight/key ratio/action ratio/inertia/momentum discussion might enjoy a class next week at our annual convention in Arlington, VA titled "Weigh-Off 101". I understand from the two instructors it will get deeper into these topics than merely a "101" approach, though all the basics will be covered, too. Some eye-opening examples of exactly where the lead can (should?) be placed along the length of the keystick will be included. Oh boy, I'll be in the front row!

David G. Hughes, RPT

Baltimore Chapter 

------------------------------
David Hughes RPT
Vintage Case Parts
Glyndon MD
(443) 522-2201

Original Message:
Sent: 07-18-2023 10:57
From: Dave Conte
Subject: Key ratio

Question about key ratios. I am about to replace the angled capstans on a 95 year old Hamburg Steinway model M grand with straight WNG capstans. I find the straight line drifts 3 mm from the balance hole #1 at 117.5mm to 120.5mm at #88. The balance rail holes are located precisely the same distance from the back of the key at #1 and #88. Key ratio of the naturals from rep center to balance hole is 1:1.89 on #1 and 1:1.94 on #88. Could this be intentional or just a manufacturing error?

------------------------------
Dave Conte, RPT

Piano Technician in Residence
The University of Tennessee
College of Music
Knoxville TN
(817) 307-5656
Owner: Rocky Top Piano
------------------------------

Since we didn't why don't you enlighten us

Mr. Love and Mr. Chernobieff,

It sure would have been sparkling (and sparring) to have the two of you present in the Action Weigh-Off 101 class offered by Mr. Reyburn and Mr. Hughes this past week at our national convention. :-)

In this discussion leverage, referring to the mechanical advantage gained by using a lever, or series of levers as you see in a piano, to magnify the force applied to an object and action ratio are used interchangeably.  If you change the AR, the product of those three levers, you necessarily change the mechanical advantage. That's just a physical fact.

Please explain to me how you can change one and not the other. I'll make it simple, let's just talk about the key lever, a simple Teeter-Totter with a 1:1 ratio (fulcrum in the middle). Please show me how you can move the fulcrum changing the ratio and not affect the mechanical advantage that that lever provides.

Please show your work

With respect to the front weight I still have no idea what you're talking about. I think you are conflating the front weight and the mass of the lead. Of course the lead moves to a different position with a lighter hammer as the FW changes to accommodate the weight of the hammer 🤫. The mass of the lead doesn't change, of course, but its new position changes the MOI of the key lever (by changing the center mass) which changes the MOI of the whole system. The lighter hammer also changes the MOI via the hammer-shank lever assembly. But the effective contribution of each is not equal. The lighter hammer reduces the MOI and the movement of the lead does too. But the contribution of the hammer weight reduction is much greater than the contribution of the slight movement of the lead in terms of MOI. You should be able to do the math if your calculations claims are true.  If not I can refer you to an article on the subject, which I've already done at least once. 

All,

I'll address two fallacies (AR and FW).

Action Ratio is NOT a component of Leverage. Because you can change the leverage and keep the same action ratio. Its just not a reliable measurement for calculating leverage. For calculating leverage accurately, you simply want the actual lengths of the parts.

Front weight. When you slide a weight backwards towards the balance rail, you are reducing the effect of the leveraged mass to manipulate down weight. So as neighboring hammers get lighter a weight gets slid further back instead of being reduced. Plus, another problem with FW is that it accepts the varying weight of the parts themselves That's why the leads often end up in non sequential locations.

Using these two inaccurate means of measurement leads to unpredictable results when different masses and leverages occur from piano to piano. Using inertia as a measurement provides a consistent numbering system that every touch of every piano can conform to.

-chris

------------------------------
Chernobieff Piano Restorations
All the elements are known, and yet no combination there of creates life. Yet we are here.
865-986-7720 (text only please)

Original Message:
Sent: 07-28-2023 14:00
From: David Love
Subject: Key ratio

Let me just add:

Chris wrote:

"When a weight is being slid along a key to match a DW target or a FW target on a scale, it is equivalent to sliding a hammer along the shank to get a SW target."

That is completely and utterly false.  Moving the hammer in on the shank to achieve a SW target changes the output on the hammer/shank assembly lever and with it the overall action ratio.  Sliding a lead along the key to achieve a specific FW target has no effect on the action ratio, zero, zip. That's a very major difference and your comment belies a fundamental understanding of this process. 

Since inertia in the system is largely a function of the AR (leverage) and mass it's trying to move (and where that mass is located), no matter how many leads you put in a key the AR remains unchanged and the relationship between AR and hammers mass remains unchanged.  The added leads required to achieve a certain BW or FW (however you want to think about it) will, to some degree, add to the inertia but the inertia problem that exists in many overleaded keyboards is not because of the excess lead, rather it's the poor relationship between the AR and hammer mass (which we refer to as SW in the Stanwood system) that is responsible for the major part of that.  The excess lead contributes some but pales in comparison to the AR/SW relationship and removing lead will not fix that problem.  Excess leading (or very high FWs) simply tell us that there's a problem.  The only way to fix a high inertia situation is to either lower the AR or lower the SW, or some combination of both. 

In the model I am using one can infer that AR/SW relationship using FW, SW, BW data to see if you have a problem, plus I can tell you what needs to be modified and by how much.  Since most of us don't work with inertia formulas because they don't give us much in terms of practical solutions (how much should I change the SW or AR by to achieve my goal), it's not very useful.  I know some programs, like Gravagne's, give an inertia number but it's of little value other than curiosity for the nerds. (Last I checked Gravagne was also still using "downweight" which doesn't tease out the friction variability and thus is somewhat antiquated.)  That's especially true because the inertia in all pianos graduates from relatively high to relatively low from bottom to top of the scale since the hammers are always decreasing in mass and, generally, the AR is remaining constant, or fairly constant.  Because of that fact the Fandrich/Rhodes system used A4 as their target note for evaluation of the entire action.  Those same formulas (whatever it was that they used) would yield something quite different if a target was chosen higher or lower in the scale and would have to be modified accordingly.

------------------------------
David Love RPT
www.davidlovepianos.com
davidlovepianos@comcast.net
415 407 8320

Original Message:
Sent: 07-28-2023 12:34
From: David Love
Subject: Key ratio

To All

I still don't know what Chris is talking about. It makes no sense. Maybe someone else can explain it to me. There's no equivalence to the examples he gave. It's like asking for further explanation and having the person repeat what they said but louder. 

------------------------------
David Love RPT
www.davidlovepianos.com
davidlovepianos@comcast.net
415 407 8320

Original Message:
Sent: 07-28-2023 09:03
From: Chris Chernobieff
Subject: Key ratio

Its a public forum David, i didn't write it to you specifically in the first place.

I guess i should put "to all" from now on.

To all,

When a weight is being slid along a key to match a DW target or a FW target on a scale, it is equivalent to sliding a hammer along the shank to get a SW target. Both methods are/would be using leverage disadvantageously and at the cost of controlling the mass and inertia.

-chris

------------------------------
Chernobieff Piano Restorations
All the elements are known, and yet no combination there of creates life. Yet we are here.
865-986-7720 (text only please)

Original Message:
Sent: 07-28-2023 01:48
From: David Love
Subject: Key ratio

Chris

I read this 3+ times. I really tried. I even tried altering the 'em-PHA-sis on different syl-LA-bles. I still have no idea what you're talking about. But don't try again on my account, please. 

------------------------------
David Love RPT
www.davidlovepianos.com
davidlovepianos@comcast.net
415 407 8320

Original Message:
Sent: 07-28-2023 01:09
From: Chris Chernobieff
Subject: Key ratio

One problem with using FW as a measure. Lets say you have 10 keys with 2 leads each. because the hammer gets lights you have to slide them backwards so they have less effect. This is an admission a lighter weight would do the same thing.

That's just one way FW screws up inertia. 

Also, saying an action is light, medium, or heavy is not inertia control. Those are ballpark guesses that use terms that are relative. Its equivalent to saying that a weighted wheel will reach the bottom of a hill slowly, in due time, or quickly. Because i use inertia as a direct measure, i can say the weighted wheel will reach the bottom in 10 seconds. With that capability inertia can be communicated to others precisely, duplicated, and the smoothness across the compass controlled unlike what you can do with FW based systems.

-chris

-chris

------------------------------
Chernobieff Piano Restorations
All the elements are known, and yet no combination there of creates life. Yet we are here.
865-986-7720 (text only please)

Original Message:
Sent: 07-24-2023 13:06
From: David Love
Subject: Key ratio

David H

Sounds like a class not to be missed.  My beta testing is more to do with determining optimum hammer weight and then calculating a specific note for note weight curve based on the set you are choosing (rather than a somewhat predetermined "zone") and then the accompanying calculated FW curve to yield a specific BW that you choose.  From those numbers I can tell if you have an inertia problem or not (either too much or not enough).   It achieves that without having to measure action ratios at all, something most techs don't seem that comfortable with plus there's an inconsistency in measurement styles and what certain ARs mean in different methods. 

But once you have those two weight curves then where to place the leads (if you're starting from scratch which most of us aren't) is certainly in interesting topic.  It's been addressed in the past as it relates to key return (the accelerated action) but in spite of that slight benefit it's interesting to note that Steinway abandoned the more leads nearer the balance pin approach in favor of the 3-2-1-0 approach of the past.  

Interesting topic though.  Sorry I can't be there.  

------------------------------
David Love RPT
www.davidlovepianos.com
davidlovepianos@comcast.net
415 407 8320

Original Message:
Sent: 07-23-2023 07:45
From: David Hughes
Subject: Key ratio

Replying to David Love, message #12: I believe the two instructors are Dean Reyburn and some guy named Hughes something.

------------------------------
David Hughes RPT
Vintage Case Parts
Glyndon MD
(443) 522-2201

Original Message:
Sent: 07-23-2023 00:03
From: David Love
Subject: Key ratio

Thanks David. Who are the two instructors?  Not going, unfortunately

------------------------------
David Love RPT
www.davidlovepianos.com
davidlovepianos@comcast.net
415 407 8320

Original Message:
Sent: 07-21-2023 09:28
From: David Hughes
Subject: Key ratio

Everyone involved in this touchweight/key ratio/action ratio/inertia/momentum discussion might enjoy a class next week at our annual convention in Arlington, VA titled "Weigh-Off 101". I understand from the two instructors it will get deeper into these topics than merely a "101" approach, though all the basics will be covered, too. Some eye-opening examples of exactly where the lead can (should?) be placed along the length of the keystick will be included. Oh boy, I'll be in the front row!

David G. Hughes, RPT

Baltimore Chapter 

------------------------------
David Hughes RPT
Vintage Case Parts
Glyndon MD
(443) 522-2201

Original Message:
Sent: 07-18-2023 10:57
From: Dave Conte
Subject: Key ratio

Question about key ratios. I am about to replace the angled capstans on a 95 year old Hamburg Steinway model M grand with straight WNG capstans. I find the straight line drifts 3 mm from the balance hole #1 at 117.5mm to 120.5mm at #88. The balance rail holes are located precisely the same distance from the back of the key at #1 and #88. Key ratio of the naturals from rep center to balance hole is 1:1.89 on #1 and 1:1.94 on #88. Could this be intentional or just a manufacturing error?

------------------------------
Dave Conte, RPT

Piano Technician in Residence
The University of Tennessee
College of Music
Knoxville TN
(817) 307-5656
Owner: Rocky Top Piano
------------------------------

David Love: First, send your checks to Dean Reyburn. He's the finacier of our little Keyboard Weigh-Off tag team! :-) Ha!

Since we didn't why don't you enlighten us

Mr. Love and Mr. Chernobieff,

It sure would have been sparkling (and sparring) to have the two of you present in the Action Weigh-Off 101 class offered by Mr. Reyburn and Mr. Hughes this past week at our national convention. :-)

In this discussion leverage, referring to the mechanical advantage gained by using a lever, or series of levers as you see in a piano, to magnify the force applied to an object and action ratio are used interchangeably.  If you change the AR, the product of those three levers, you necessarily change the mechanical advantage. That's just a physical fact.

Please explain to me how you can change one and not the other. I'll make it simple, let's just talk about the key lever, a simple Teeter-Totter with a 1:1 ratio (fulcrum in the middle). Please show me how you can move the fulcrum changing the ratio and not affect the mechanical advantage that that lever provides.

Please show your work

With respect to the front weight I still have no idea what you're talking about. I think you are conflating the front weight and the mass of the lead. Of course the lead moves to a different position with a lighter hammer as the FW changes to accommodate the weight of the hammer 🤫. The mass of the lead doesn't change, of course, but its new position changes the MOI of the key lever (by changing the center mass) which changes the MOI of the whole system. The lighter hammer also changes the MOI via the hammer-shank lever assembly. But the effective contribution of each is not equal. The lighter hammer reduces the MOI and the movement of the lead does too. But the contribution of the hammer weight reduction is much greater than the contribution of the slight movement of the lead in terms of MOI. You should be able to do the math if your calculations claims are true.  If not I can refer you to an article on the subject, which I've already done at least once. 

All,

I'll address two fallacies (AR and FW).

Action Ratio is NOT a component of Leverage. Because you can change the leverage and keep the same action ratio. Its just not a reliable measurement for calculating leverage. For calculating leverage accurately, you simply want the actual lengths of the parts.

Front weight. When you slide a weight backwards towards the balance rail, you are reducing the effect of the leveraged mass to manipulate down weight. So as neighboring hammers get lighter a weight gets slid further back instead of being reduced. Plus, another problem with FW is that it accepts the varying weight of the parts themselves That's why the leads often end up in non sequential locations.

Using these two inaccurate means of measurement leads to unpredictable results when different masses and leverages occur from piano to piano. Using inertia as a measurement provides a consistent numbering system that every touch of every piano can conform to.

-chris

------------------------------
Chernobieff Piano Restorations
All the elements are known, and yet no combination there of creates life. Yet we are here.
865-986-7720 (text only please)

Original Message:
Sent: 07-28-2023 14:00
From: David Love
Subject: Key ratio

Let me just add:

Chris wrote:

"When a weight is being slid along a key to match a DW target or a FW target on a scale, it is equivalent to sliding a hammer along the shank to get a SW target."

That is completely and utterly false.  Moving the hammer in on the shank to achieve a SW target changes the output on the hammer/shank assembly lever and with it the overall action ratio.  Sliding a lead along the key to achieve a specific FW target has no effect on the action ratio, zero, zip. That's a very major difference and your comment belies a fundamental understanding of this process. 

Since inertia in the system is largely a function of the AR (leverage) and mass it's trying to move (and where that mass is located), no matter how many leads you put in a key the AR remains unchanged and the relationship between AR and hammers mass remains unchanged.  The added leads required to achieve a certain BW or FW (however you want to think about it) will, to some degree, add to the inertia but the inertia problem that exists in many overleaded keyboards is not because of the excess lead, rather it's the poor relationship between the AR and hammer mass (which we refer to as SW in the Stanwood system) that is responsible for the major part of that.  The excess lead contributes some but pales in comparison to the AR/SW relationship and removing lead will not fix that problem.  Excess leading (or very high FWs) simply tell us that there's a problem.  The only way to fix a high inertia situation is to either lower the AR or lower the SW, or some combination of both. 

In the model I am using one can infer that AR/SW relationship using FW, SW, BW data to see if you have a problem, plus I can tell you what needs to be modified and by how much.  Since most of us don't work with inertia formulas because they don't give us much in terms of practical solutions (how much should I change the SW or AR by to achieve my goal), it's not very useful.  I know some programs, like Gravagne's, give an inertia number but it's of little value other than curiosity for the nerds. (Last I checked Gravagne was also still using "downweight" which doesn't tease out the friction variability and thus is somewhat antiquated.)  That's especially true because the inertia in all pianos graduates from relatively high to relatively low from bottom to top of the scale since the hammers are always decreasing in mass and, generally, the AR is remaining constant, or fairly constant.  Because of that fact the Fandrich/Rhodes system used A4 as their target note for evaluation of the entire action.  Those same formulas (whatever it was that they used) would yield something quite different if a target was chosen higher or lower in the scale and would have to be modified accordingly.

------------------------------
David Love RPT
www.davidlovepianos.com
davidlovepianos@comcast.net
415 407 8320

Original Message:
Sent: 07-28-2023 12:34
From: David Love
Subject: Key ratio

To All

I still don't know what Chris is talking about. It makes no sense. Maybe someone else can explain it to me. There's no equivalence to the examples he gave. It's like asking for further explanation and having the person repeat what they said but louder. 

------------------------------
David Love RPT
www.davidlovepianos.com
davidlovepianos@comcast.net
415 407 8320

Original Message:
Sent: 07-28-2023 09:03
From: Chris Chernobieff
Subject: Key ratio

Its a public forum David, i didn't write it to you specifically in the first place.

I guess i should put "to all" from now on.

To all,

When a weight is being slid along a key to match a DW target or a FW target on a scale, it is equivalent to sliding a hammer along the shank to get a SW target. Both methods are/would be using leverage disadvantageously and at the cost of controlling the mass and inertia.

-chris

------------------------------
Chernobieff Piano Restorations
All the elements are known, and yet no combination there of creates life. Yet we are here.
865-986-7720 (text only please)

Original Message:
Sent: 07-28-2023 01:48
From: David Love
Subject: Key ratio

Chris

I read this 3+ times. I really tried. I even tried altering the 'em-PHA-sis on different syl-LA-bles. I still have no idea what you're talking about. But don't try again on my account, please. 

------------------------------
David Love RPT
www.davidlovepianos.com
davidlovepianos@comcast.net
415 407 8320

Original Message:
Sent: 07-28-2023 01:09
From: Chris Chernobieff
Subject: Key ratio

One problem with using FW as a measure. Lets say you have 10 keys with 2 leads each. because the hammer gets lights you have to slide them backwards so they have less effect. This is an admission a lighter weight would do the same thing.

That's just one way FW screws up inertia. 

Also, saying an action is light, medium, or heavy is not inertia control. Those are ballpark guesses that use terms that are relative. Its equivalent to saying that a weighted wheel will reach the bottom of a hill slowly, in due time, or quickly. Because i use inertia as a direct measure, i can say the weighted wheel will reach the bottom in 10 seconds. With that capability inertia can be communicated to others precisely, duplicated, and the smoothness across the compass controlled unlike what you can do with FW based systems.

-chris

-chris

------------------------------
Chernobieff Piano Restorations
All the elements are known, and yet no combination there of creates life. Yet we are here.
865-986-7720 (text only please)

Original Message:
Sent: 07-24-2023 13:06
From: David Love
Subject: Key ratio

David H

Sounds like a class not to be missed.  My beta testing is more to do with determining optimum hammer weight and then calculating a specific note for note weight curve based on the set you are choosing (rather than a somewhat predetermined "zone") and then the accompanying calculated FW curve to yield a specific BW that you choose.  From those numbers I can tell if you have an inertia problem or not (either too much or not enough).   It achieves that without having to measure action ratios at all, something most techs don't seem that comfortable with plus there's an inconsistency in measurement styles and what certain ARs mean in different methods. 

But once you have those two weight curves then where to place the leads (if you're starting from scratch which most of us aren't) is certainly in interesting topic.  It's been addressed in the past as it relates to key return (the accelerated action) but in spite of that slight benefit it's interesting to note that Steinway abandoned the more leads nearer the balance pin approach in favor of the 3-2-1-0 approach of the past.  

Interesting topic though.  Sorry I can't be there.  

------------------------------
David Love RPT
www.davidlovepianos.com
davidlovepianos@comcast.net
415 407 8320

Original Message:
Sent: 07-23-2023 07:45
From: David Hughes
Subject: Key ratio

Replying to David Love, message #12: I believe the two instructors are Dean Reyburn and some guy named Hughes something.

------------------------------
David Hughes RPT
Vintage Case Parts
Glyndon MD
(443) 522-2201

Original Message:
Sent: 07-23-2023 00:03
From: David Love
Subject: Key ratio

Thanks David. Who are the two instructors?  Not going, unfortunately

------------------------------
David Love RPT
www.davidlovepianos.com
davidlovepianos@comcast.net
415 407 8320

Original Message:
Sent: 07-21-2023 09:28
From: David Hughes
Subject: Key ratio

Everyone involved in this touchweight/key ratio/action ratio/inertia/momentum discussion might enjoy a class next week at our annual convention in Arlington, VA titled "Weigh-Off 101". I understand from the two instructors it will get deeper into these topics than merely a "101" approach, though all the basics will be covered, too. Some eye-opening examples of exactly where the lead can (should?) be placed along the length of the keystick will be included. Oh boy, I'll be in the front row!

David G. Hughes, RPT

Baltimore Chapter 

------------------------------
David Hughes RPT
Vintage Case Parts
Glyndon MD
(443) 522-2201

Original Message:
Sent: 07-18-2023 10:57
From: Dave Conte
Subject: Key ratio

Question about key ratios. I am about to replace the angled capstans on a 95 year old Hamburg Steinway model M grand with straight WNG capstans. I find the straight line drifts 3 mm from the balance hole #1 at 117.5mm to 120.5mm at #88. The balance rail holes are located precisely the same distance from the back of the key at #1 and #88. Key ratio of the naturals from rep center to balance hole is 1:1.89 on #1 and 1:1.94 on #88. Could this be intentional or just a manufacturing error?

------------------------------
Dave Conte, RPT

Piano Technician in Residence
The University of Tennessee
College of Music
Knoxville TN
(817) 307-5656
Owner: Rocky Top Piano
------------------------------

That's not particularly helpful.  Personally, I'm generally an advocate for classes being given by those who aren't selling something, though if I had a key set to be made Dean is where I'd send it.

Why don't you post an outline of the class in the shared files area.  I'd be curious to know what was covered.  

David Love: First, send your checks to Dean Reyburn. He's the finacier of our little Keyboard Weigh-Off tag team! :-) Ha!

Since we didn't why don't you enlighten us

Mr. Love and Mr. Chernobieff,

It sure would have been sparkling (and sparring) to have the two of you present in the Action Weigh-Off 101 class offered by Mr. Reyburn and Mr. Hughes this past week at our national convention. :-)

In this discussion leverage, referring to the mechanical advantage gained by using a lever, or series of levers as you see in a piano, to magnify the force applied to an object and action ratio are used interchangeably.  If you change the AR, the product of those three levers, you necessarily change the mechanical advantage. That's just a physical fact.

Please explain to me how you can change one and not the other. I'll make it simple, let's just talk about the key lever, a simple Teeter-Totter with a 1:1 ratio (fulcrum in the middle). Please show me how you can move the fulcrum changing the ratio and not affect the mechanical advantage that that lever provides.

Please show your work

With respect to the front weight I still have no idea what you're talking about. I think you are conflating the front weight and the mass of the lead. Of course the lead moves to a different position with a lighter hammer as the FW changes to accommodate the weight of the hammer 🤫. The mass of the lead doesn't change, of course, but its new position changes the MOI of the key lever (by changing the center mass) which changes the MOI of the whole system. The lighter hammer also changes the MOI via the hammer-shank lever assembly. But the effective contribution of each is not equal. The lighter hammer reduces the MOI and the movement of the lead does too. But the contribution of the hammer weight reduction is much greater than the contribution of the slight movement of the lead in terms of MOI. You should be able to do the math if your calculations claims are true.  If not I can refer you to an article on the subject, which I've already done at least once. 

All,

I'll address two fallacies (AR and FW).

Action Ratio is NOT a component of Leverage. Because you can change the leverage and keep the same action ratio. Its just not a reliable measurement for calculating leverage. For calculating leverage accurately, you simply want the actual lengths of the parts.

Front weight. When you slide a weight backwards towards the balance rail, you are reducing the effect of the leveraged mass to manipulate down weight. So as neighboring hammers get lighter a weight gets slid further back instead of being reduced. Plus, another problem with FW is that it accepts the varying weight of the parts themselves That's why the leads often end up in non sequential locations.

Using these two inaccurate means of measurement leads to unpredictable results when different masses and leverages occur from piano to piano. Using inertia as a measurement provides a consistent numbering system that every touch of every piano can conform to.

-chris

------------------------------
Chernobieff Piano Restorations
All the elements are known, and yet no combination there of creates life. Yet we are here.
865-986-7720 (text only please)

Original Message:
Sent: 07-28-2023 14:00
From: David Love
Subject: Key ratio

Let me just add:

Chris wrote:

"When a weight is being slid along a key to match a DW target or a FW target on a scale, it is equivalent to sliding a hammer along the shank to get a SW target."

That is completely and utterly false.  Moving the hammer in on the shank to achieve a SW target changes the output on the hammer/shank assembly lever and with it the overall action ratio.  Sliding a lead along the key to achieve a specific FW target has no effect on the action ratio, zero, zip. That's a very major difference and your comment belies a fundamental understanding of this process. 

Since inertia in the system is largely a function of the AR (leverage) and mass it's trying to move (and where that mass is located), no matter how many leads you put in a key the AR remains unchanged and the relationship between AR and hammers mass remains unchanged.  The added leads required to achieve a certain BW or FW (however you want to think about it) will, to some degree, add to the inertia but the inertia problem that exists in many overleaded keyboards is not because of the excess lead, rather it's the poor relationship between the AR and hammer mass (which we refer to as SW in the Stanwood system) that is responsible for the major part of that.  The excess lead contributes some but pales in comparison to the AR/SW relationship and removing lead will not fix that problem.  Excess leading (or very high FWs) simply tell us that there's a problem.  The only way to fix a high inertia situation is to either lower the AR or lower the SW, or some combination of both. 

In the model I am using one can infer that AR/SW relationship using FW, SW, BW data to see if you have a problem, plus I can tell you what needs to be modified and by how much.  Since most of us don't work with inertia formulas because they don't give us much in terms of practical solutions (how much should I change the SW or AR by to achieve my goal), it's not very useful.  I know some programs, like Gravagne's, give an inertia number but it's of little value other than curiosity for the nerds. (Last I checked Gravagne was also still using "downweight" which doesn't tease out the friction variability and thus is somewhat antiquated.)  That's especially true because the inertia in all pianos graduates from relatively high to relatively low from bottom to top of the scale since the hammers are always decreasing in mass and, generally, the AR is remaining constant, or fairly constant.  Because of that fact the Fandrich/Rhodes system used A4 as their target note for evaluation of the entire action.  Those same formulas (whatever it was that they used) would yield something quite different if a target was chosen higher or lower in the scale and would have to be modified accordingly.

------------------------------
David Love RPT
www.davidlovepianos.com
davidlovepianos@comcast.net
415 407 8320

Original Message:
Sent: 07-28-2023 12:34
From: David Love
Subject: Key ratio

To All

I still don't know what Chris is talking about. It makes no sense. Maybe someone else can explain it to me. There's no equivalence to the examples he gave. It's like asking for further explanation and having the person repeat what they said but louder. 

------------------------------
David Love RPT
www.davidlovepianos.com
davidlovepianos@comcast.net
415 407 8320

Original Message:
Sent: 07-28-2023 09:03
From: Chris Chernobieff
Subject: Key ratio

Its a public forum David, i didn't write it to you specifically in the first place.

I guess i should put "to all" from now on.

To all,

When a weight is being slid along a key to match a DW target or a FW target on a scale, it is equivalent to sliding a hammer along the shank to get a SW target. Both methods are/would be using leverage disadvantageously and at the cost of controlling the mass and inertia.

-chris

------------------------------
Chernobieff Piano Restorations
All the elements are known, and yet no combination there of creates life. Yet we are here.
865-986-7720 (text only please)

Original Message:
Sent: 07-28-2023 01:48
From: David Love
Subject: Key ratio

Chris

I read this 3+ times. I really tried. I even tried altering the 'em-PHA-sis on different syl-LA-bles. I still have no idea what you're talking about. But don't try again on my account, please. 

------------------------------
David Love RPT
www.davidlovepianos.com
davidlovepianos@comcast.net
415 407 8320

Original Message:
Sent: 07-28-2023 01:09
From: Chris Chernobieff
Subject: Key ratio

One problem with using FW as a measure. Lets say you have 10 keys with 2 leads each. because the hammer gets lights you have to slide them backwards so they have less effect. This is an admission a lighter weight would do the same thing.

That's just one way FW screws up inertia. 

Also, saying an action is light, medium, or heavy is not inertia control. Those are ballpark guesses that use terms that are relative. Its equivalent to saying that a weighted wheel will reach the bottom of a hill slowly, in due time, or quickly. Because i use inertia as a direct measure, i can say the weighted wheel will reach the bottom in 10 seconds. With that capability inertia can be communicated to others precisely, duplicated, and the smoothness across the compass controlled unlike what you can do with FW based systems.

-chris

-chris

------------------------------
Chernobieff Piano Restorations
All the elements are known, and yet no combination there of creates life. Yet we are here.
865-986-7720 (text only please)

Original Message:
Sent: 07-24-2023 13:06
From: David Love
Subject: Key ratio

David H

Sounds like a class not to be missed.  My beta testing is more to do with determining optimum hammer weight and then calculating a specific note for note weight curve based on the set you are choosing (rather than a somewhat predetermined "zone") and then the accompanying calculated FW curve to yield a specific BW that you choose.  From those numbers I can tell if you have an inertia problem or not (either too much or not enough).   It achieves that without having to measure action ratios at all, something most techs don't seem that comfortable with plus there's an inconsistency in measurement styles and what certain ARs mean in different methods. 

But once you have those two weight curves then where to place the leads (if you're starting from scratch which most of us aren't) is certainly in interesting topic.  It's been addressed in the past as it relates to key return (the accelerated action) but in spite of that slight benefit it's interesting to note that Steinway abandoned the more leads nearer the balance pin approach in favor of the 3-2-1-0 approach of the past.  

Interesting topic though.  Sorry I can't be there.  

------------------------------
David Love RPT
www.davidlovepianos.com
davidlovepianos@comcast.net
415 407 8320

Original Message:
Sent: 07-23-2023 07:45
From: David Hughes
Subject: Key ratio

Replying to David Love, message #12: I believe the two instructors are Dean Reyburn and some guy named Hughes something.

------------------------------
David Hughes RPT
Vintage Case Parts
Glyndon MD
(443) 522-2201

Original Message:
Sent: 07-23-2023 00:03
From: David Love
Subject: Key ratio

Thanks David. Who are the two instructors?  Not going, unfortunately

------------------------------
David Love RPT
www.davidlovepianos.com
davidlovepianos@comcast.net
415 407 8320

Original Message:
Sent: 07-21-2023 09:28
From: David Hughes
Subject: Key ratio

Everyone involved in this touchweight/key ratio/action ratio/inertia/momentum discussion might enjoy a class next week at our annual convention in Arlington, VA titled "Weigh-Off 101". I understand from the two instructors it will get deeper into these topics than merely a "101" approach, though all the basics will be covered, too. Some eye-opening examples of exactly where the lead can (should?) be placed along the length of the keystick will be included. Oh boy, I'll be in the front row!

David G. Hughes, RPT

Baltimore Chapter 

------------------------------
David Hughes RPT
Vintage Case Parts
Glyndon MD
(443) 522-2201

Original Message:
Sent: 07-18-2023 10:57
From: Dave Conte
Subject: Key ratio

Question about key ratios. I am about to replace the angled capstans on a 95 year old Hamburg Steinway model M grand with straight WNG capstans. I find the straight line drifts 3 mm from the balance hole #1 at 117.5mm to 120.5mm at #88. The balance rail holes are located precisely the same distance from the back of the key at #1 and #88. Key ratio of the naturals from rep center to balance hole is 1:1.89 on #1 and 1:1.94 on #88. Could this be intentional or just a manufacturing error?

------------------------------
Dave Conte, RPT

Piano Technician in Residence
The University of Tennessee
College of Music
Knoxville TN
(817) 307-5656
Owner: Rocky Top Piano
------------------------------

David Love: I was joking about the $$. :-). Dean Reyburn was completely professional and education-oriented in class and made no sales pitch for his keyboards whatsoever. If anything, it was I who praised his work. And yes, I think he and I would be happy to post our two-page class handout. Stay tuned.

David G. Hughes, RPT

Baltimore Chapter 

------------------------------
David Hughes RPT
Vintage Case Parts
Glyndon MD
(443) 522-2201

Original Message:
Sent: 07-31-2023 11:49
From: David Love
Subject: Key ratio

That's not particularly helpful.  Personally, I'm generally an advocate for classes being given by those who aren't selling something, though if I had a key set to be made Dean is where I'd send it.

Why don't you post an outline of the class in the shared files area.  I'd be curious to know what was covered.  

------------------------------
David Love RPT
www.davidlovepianos.com
davidlovepianos@comcast.net
415 407 8320

Original Message:
Sent: 07-31-2023 10:57
From: David Hughes
Subject: Key ratio

David Love: First, send your checks to Dean Reyburn. He's the finacier of our little Keyboard Weigh-Off tag team! :-) Ha!

------------------------------
David Hughes RPT
Vintage Case Parts
Glyndon MD
(443) 522-2201

Original Message:
Sent: 07-31-2023 10:20
From: David Love
Subject: Key ratio

Since we didn't why don't you enlighten us

------------------------------
David Love RPT
www.davidlovepianos.com
davidlovepianos@comcast.net
415 407 8320

Original Message:
Sent: 07-30-2023 10:23
From: David Hughes
Subject: Key ratio

Mr. Love and Mr. Chernobieff,

It sure would have been sparkling (and sparring) to have the two of you present in the Action Weigh-Off 101 class offered by Mr. Reyburn and Mr. Hughes this past week at our national convention. :-)

------------------------------
David Hughes RPT
Vintage Case Parts
Glyndon MD
(443) 522-2201

Original Message:
Sent: 07-29-2023 23:23
From: David Love
Subject: Key ratio

In this discussion leverage, referring to the mechanical advantage gained by using a lever, or series of levers as you see in a piano, to magnify the force applied to an object and action ratio are used interchangeably.  If you change the AR, the product of those three levers, you necessarily change the mechanical advantage. That's just a physical fact.

Please explain to me how you can change one and not the other. I'll make it simple, let's just talk about the key lever, a simple Teeter-Totter with a 1:1 ratio (fulcrum in the middle). Please show me how you can move the fulcrum changing the ratio and not affect the mechanical advantage that that lever provides.

Please show your work

With respect to the front weight I still have no idea what you're talking about. I think you are conflating the front weight and the mass of the lead. Of course the lead moves to a different position with a lighter hammer as the FW changes to accommodate the weight of the hammer 🤫. The mass of the lead doesn't change, of course, but its new position changes the MOI of the key lever (by changing the center mass) which changes the MOI of the whole system. The lighter hammer also changes the MOI via the hammer-shank lever assembly. But the effective contribution of each is not equal. The lighter hammer reduces the MOI and the movement of the lead does too. But the contribution of the hammer weight reduction is much greater than the contribution of the slight movement of the lead in terms of MOI. You should be able to do the math if your calculations claims are true.  If not I can refer you to an article on the subject, which I've already done at least once. 

------------------------------
David Love RPT
www.davidlovepianos.com
davidlovepianos@comcast.net
415 407 8320

Original Message:
Sent: 07-29-2023 11:18
From: Chris Chernobieff
Subject: Key ratio

All,

I'll address two fallacies (AR and FW).

Action Ratio is NOT a component of Leverage. Because you can change the leverage and keep the same action ratio. Its just not a reliable measurement for calculating leverage. For calculating leverage accurately, you simply want the actual lengths of the parts.

Front weight. When you slide a weight backwards towards the balance rail, you are reducing the effect of the leveraged mass to manipulate down weight. So as neighboring hammers get lighter a weight gets slid further back instead of being reduced. Plus, another problem with FW is that it accepts the varying weight of the parts themselves That's why the leads often end up in non sequential locations.

Using these two inaccurate means of measurement leads to unpredictable results when different masses and leverages occur from piano to piano. Using inertia as a measurement provides a consistent numbering system that every touch of every piano can conform to.

-chris

------------------------------
Chernobieff Piano Restorations
All the elements are known, and yet no combination there of creates life. Yet we are here.
865-986-7720 (text only please)

Original Message:
Sent: 07-28-2023 14:00
From: David Love
Subject: Key ratio

Let me just add:

Chris wrote:

"When a weight is being slid along a key to match a DW target or a FW target on a scale, it is equivalent to sliding a hammer along the shank to get a SW target."

That is completely and utterly false.  Moving the hammer in on the shank to achieve a SW target changes the output on the hammer/shank assembly lever and with it the overall action ratio.  Sliding a lead along the key to achieve a specific FW target has no effect on the action ratio, zero, zip. That's a very major difference and your comment belies a fundamental understanding of this process. 

Since inertia in the system is largely a function of the AR (leverage) and mass it's trying to move (and where that mass is located), no matter how many leads you put in a key the AR remains unchanged and the relationship between AR and hammers mass remains unchanged.  The added leads required to achieve a certain BW or FW (however you want to think about it) will, to some degree, add to the inertia but the inertia problem that exists in many overleaded keyboards is not because of the excess lead, rather it's the poor relationship between the AR and hammer mass (which we refer to as SW in the Stanwood system) that is responsible for the major part of that.  The excess lead contributes some but pales in comparison to the AR/SW relationship and removing lead will not fix that problem.  Excess leading (or very high FWs) simply tell us that there's a problem.  The only way to fix a high inertia situation is to either lower the AR or lower the SW, or some combination of both. 

In the model I am using one can infer that AR/SW relationship using FW, SW, BW data to see if you have a problem, plus I can tell you what needs to be modified and by how much.  Since most of us don't work with inertia formulas because they don't give us much in terms of practical solutions (how much should I change the SW or AR by to achieve my goal), it's not very useful.  I know some programs, like Gravagne's, give an inertia number but it's of little value other than curiosity for the nerds. (Last I checked Gravagne was also still using "downweight" which doesn't tease out the friction variability and thus is somewhat antiquated.)  That's especially true because the inertia in all pianos graduates from relatively high to relatively low from bottom to top of the scale since the hammers are always decreasing in mass and, generally, the AR is remaining constant, or fairly constant.  Because of that fact the Fandrich/Rhodes system used A4 as their target note for evaluation of the entire action.  Those same formulas (whatever it was that they used) would yield something quite different if a target was chosen higher or lower in the scale and would have to be modified accordingly.

------------------------------
David Love RPT
www.davidlovepianos.com
davidlovepianos@comcast.net
415 407 8320

Original Message:
Sent: 07-28-2023 12:34
From: David Love
Subject: Key ratio

To All

I still don't know what Chris is talking about. It makes no sense. Maybe someone else can explain it to me. There's no equivalence to the examples he gave. It's like asking for further explanation and having the person repeat what they said but louder. 

------------------------------
David Love RPT
www.davidlovepianos.com
davidlovepianos@comcast.net
415 407 8320

Original Message:
Sent: 07-28-2023 09:03
From: Chris Chernobieff
Subject: Key ratio

Its a public forum David, i didn't write it to you specifically in the first place.

I guess i should put "to all" from now on.

To all,

When a weight is being slid along a key to match a DW target or a FW target on a scale, it is equivalent to sliding a hammer along the shank to get a SW target. Both methods are/would be using leverage disadvantageously and at the cost of controlling the mass and inertia.

-chris

------------------------------
Chernobieff Piano Restorations
All the elements are known, and yet no combination there of creates life. Yet we are here.
865-986-7720 (text only please)

Original Message:
Sent: 07-28-2023 01:48
From: David Love
Subject: Key ratio

Chris

I read this 3+ times. I really tried. I even tried altering the 'em-PHA-sis on different syl-LA-bles. I still have no idea what you're talking about. But don't try again on my account, please. 

------------------------------
David Love RPT
www.davidlovepianos.com
davidlovepianos@comcast.net
415 407 8320

Original Message:
Sent: 07-28-2023 01:09
From: Chris Chernobieff
Subject: Key ratio

One problem with using FW as a measure. Lets say you have 10 keys with 2 leads each. because the hammer gets lights you have to slide them backwards so they have less effect. This is an admission a lighter weight would do the same thing.

That's just one way FW screws up inertia. 

Also, saying an action is light, medium, or heavy is not inertia control. Those are ballpark guesses that use terms that are relative. Its equivalent to saying that a weighted wheel will reach the bottom of a hill slowly, in due time, or quickly. Because i use inertia as a direct measure, i can say the weighted wheel will reach the bottom in 10 seconds. With that capability inertia can be communicated to others precisely, duplicated, and the smoothness across the compass controlled unlike what you can do with FW based systems.

-chris

-chris

------------------------------
Chernobieff Piano Restorations
All the elements are known, and yet no combination there of creates life. Yet we are here.
865-986-7720 (text only please)

Original Message:
Sent: 07-24-2023 13:06
From: David Love
Subject: Key ratio

David H

Sounds like a class not to be missed.  My beta testing is more to do with determining optimum hammer weight and then calculating a specific note for note weight curve based on the set you are choosing (rather than a somewhat predetermined "zone") and then the accompanying calculated FW curve to yield a specific BW that you choose.  From those numbers I can tell if you have an inertia problem or not (either too much or not enough).   It achieves that without having to measure action ratios at all, something most techs don't seem that comfortable with plus there's an inconsistency in measurement styles and what certain ARs mean in different methods. 

But once you have those two weight curves then where to place the leads (if you're starting from scratch which most of us aren't) is certainly in interesting topic.  It's been addressed in the past as it relates to key return (the accelerated action) but in spite of that slight benefit it's interesting to note that Steinway abandoned the more leads nearer the balance pin approach in favor of the 3-2-1-0 approach of the past.  

Interesting topic though.  Sorry I can't be there.  

------------------------------
David Love RPT
www.davidlovepianos.com
davidlovepianos@comcast.net
415 407 8320

Original Message:
Sent: 07-23-2023 07:45
From: David Hughes
Subject: Key ratio

Replying to David Love, message #12: I believe the two instructors are Dean Reyburn and some guy named Hughes something.

------------------------------
David Hughes RPT
Vintage Case Parts
Glyndon MD
(443) 522-2201

Original Message:
Sent: 07-23-2023 00:03
From: David Love
Subject: Key ratio

Thanks David. Who are the two instructors?  Not going, unfortunately

------------------------------
David Love RPT
www.davidlovepianos.com
davidlovepianos@comcast.net
415 407 8320

Original Message:
Sent: 07-21-2023 09:28
From: David Hughes
Subject: Key ratio

Everyone involved in this touchweight/key ratio/action ratio/inertia/momentum discussion might enjoy a class next week at our annual convention in Arlington, VA titled "Weigh-Off 101". I understand from the two instructors it will get deeper into these topics than merely a "101" approach, though all the basics will be covered, too. Some eye-opening examples of exactly where the lead can (should?) be placed along the length of the keystick will be included. Oh boy, I'll be in the front row!

David G. Hughes, RPT

Baltimore Chapter 

------------------------------
David Hughes RPT
Vintage Case Parts
Glyndon MD
(443) 522-2201

Original Message:
Sent: 07-18-2023 10:57
From: Dave Conte
Subject: Key ratio

Question about key ratios. I am about to replace the angled capstans on a 95 year old Hamburg Steinway model M grand with straight WNG capstans. I find the straight line drifts 3 mm from the balance hole #1 at 117.5mm to 120.5mm at #88. The balance rail holes are located precisely the same distance from the back of the key at #1 and #88. Key ratio of the naturals from rep center to balance hole is 1:1.89 on #1 and 1:1.94 on #88. Could this be intentional or just a manufacturing error?

------------------------------
Dave Conte, RPT

Piano Technician in Residence
The University of Tennessee
College of Music
Knoxville TN
(817) 307-5656
Owner: Rocky Top Piano
------------------------------

You said that we should have both attended the class. Would that I could have.  The implication is that both our positions require some clarification or correction.  Why don't you do that then.  To say that  we should have attended the class is of little use.  Admittedly, I don't like being lumped together with spurious arguments.  

FWIW, I stand by my position on this.  I have no idea if it relates to the class or not.  I've heard and attended plenty of classes given by many reputable people on the issue of action geometry, action measurement, action ratios, inertia, yada yada yada.  Interesting that there are lots of different approaches each yielding a somewhat different outcome and everyone sticks to their belief. 

The information I was presenting was a very tried and true way of determining hammer weight and AR relationships.  Your comments seems to suggest otherwise.  Please elaborate. 

------------------------------
David Love RPT
www.davidlovepianos.com
davidlovepianos@comcast.net
415 407 8320

Original Message:
Sent: 07-31-2023 11:57
From: David Hughes
Subject: Key ratio

David Love: I was joking about the $$. :-). Dean Reyburn was completely professional and education-oriented in class and made no sales pitch for his keyboards whatsoever. If anything, it was I who praised his work. And yes, I think he and I would be happy to post our two-page class handout. Stay tuned.

David G. Hughes, RPT

Baltimore Chapter 

------------------------------
David Hughes RPT
Vintage Case Parts
Glyndon MD
(443) 522-2201

Original Message:
Sent: 07-31-2023 11:49
From: David Love
Subject: Key ratio

That's not particularly helpful.  Personally, I'm generally an advocate for classes being given by those who aren't selling something, though if I had a key set to be made Dean is where I'd send it.

Why don't you post an outline of the class in the shared files area.  I'd be curious to know what was covered.  

------------------------------
David Love RPT
www.davidlovepianos.com
davidlovepianos@comcast.net
415 407 8320

Original Message:
Sent: 07-31-2023 10:57
From: David Hughes
Subject: Key ratio

David Love: First, send your checks to Dean Reyburn. He's the finacier of our little Keyboard Weigh-Off tag team! :-) Ha!

------------------------------
David Hughes RPT
Vintage Case Parts
Glyndon MD
(443) 522-2201

Original Message:
Sent: 07-31-2023 10:20
From: David Love
Subject: Key ratio

Since we didn't why don't you enlighten us

------------------------------
David Love RPT
www.davidlovepianos.com
davidlovepianos@comcast.net
415 407 8320

Original Message:
Sent: 07-30-2023 10:23
From: David Hughes
Subject: Key ratio

Mr. Love and Mr. Chernobieff,

It sure would have been sparkling (and sparring) to have the two of you present in the Action Weigh-Off 101 class offered by Mr. Reyburn and Mr. Hughes this past week at our national convention. :-)

------------------------------
David Hughes RPT
Vintage Case Parts
Glyndon MD
(443) 522-2201

Original Message:
Sent: 07-29-2023 23:23
From: David Love
Subject: Key ratio

In this discussion leverage, referring to the mechanical advantage gained by using a lever, or series of levers as you see in a piano, to magnify the force applied to an object and action ratio are used interchangeably.  If you change the AR, the product of those three levers, you necessarily change the mechanical advantage. That's just a physical fact.

Please explain to me how you can change one and not the other. I'll make it simple, let's just talk about the key lever, a simple Teeter-Totter with a 1:1 ratio (fulcrum in the middle). Please show me how you can move the fulcrum changing the ratio and not affect the mechanical advantage that that lever provides.

Please show your work

With respect to the front weight I still have no idea what you're talking about. I think you are conflating the front weight and the mass of the lead. Of course the lead moves to a different position with a lighter hammer as the FW changes to accommodate the weight of the hammer 🤫. The mass of the lead doesn't change, of course, but its new position changes the MOI of the key lever (by changing the center mass) which changes the MOI of the whole system. The lighter hammer also changes the MOI via the hammer-shank lever assembly. But the effective contribution of each is not equal. The lighter hammer reduces the MOI and the movement of the lead does too. But the contribution of the hammer weight reduction is much greater than the contribution of the slight movement of the lead in terms of MOI. You should be able to do the math if your calculations claims are true.  If not I can refer you to an article on the subject, which I've already done at least once. 

------------------------------
David Love RPT
www.davidlovepianos.com
davidlovepianos@comcast.net
415 407 8320

Original Message:
Sent: 07-29-2023 11:18
From: Chris Chernobieff
Subject: Key ratio

All,

I'll address two fallacies (AR and FW).

Action Ratio is NOT a component of Leverage. Because you can change the leverage and keep the same action ratio. Its just not a reliable measurement for calculating leverage. For calculating leverage accurately, you simply want the actual lengths of the parts.

Front weight. When you slide a weight backwards towards the balance rail, you are reducing the effect of the leveraged mass to manipulate down weight. So as neighboring hammers get lighter a weight gets slid further back instead of being reduced. Plus, another problem with FW is that it accepts the varying weight of the parts themselves That's why the leads often end up in non sequential locations.

Using these two inaccurate means of measurement leads to unpredictable results when different masses and leverages occur from piano to piano. Using inertia as a measurement provides a consistent numbering system that every touch of every piano can conform to.

-chris

------------------------------
Chernobieff Piano Restorations
All the elements are known, and yet no combination there of creates life. Yet we are here.
865-986-7720 (text only please)

Original Message:
Sent: 07-28-2023 14:00
From: David Love
Subject: Key ratio

Let me just add:

Chris wrote:

"When a weight is being slid along a key to match a DW target or a FW target on a scale, it is equivalent to sliding a hammer along the shank to get a SW target."

That is completely and utterly false.  Moving the hammer in on the shank to achieve a SW target changes the output on the hammer/shank assembly lever and with it the overall action ratio.  Sliding a lead along the key to achieve a specific FW target has no effect on the action ratio, zero, zip. That's a very major difference and your comment belies a fundamental understanding of this process. 

Since inertia in the system is largely a function of the AR (leverage) and mass it's trying to move (and where that mass is located), no matter how many leads you put in a key the AR remains unchanged and the relationship between AR and hammers mass remains unchanged.  The added leads required to achieve a certain BW or FW (however you want to think about it) will, to some degree, add to the inertia but the inertia problem that exists in many overleaded keyboards is not because of the excess lead, rather it's the poor relationship between the AR and hammer mass (which we refer to as SW in the Stanwood system) that is responsible for the major part of that.  The excess lead contributes some but pales in comparison to the AR/SW relationship and removing lead will not fix that problem.  Excess leading (or very high FWs) simply tell us that there's a problem.  The only way to fix a high inertia situation is to either lower the AR or lower the SW, or some combination of both. 

In the model I am using one can infer that AR/SW relationship using FW, SW, BW data to see if you have a problem, plus I can tell you what needs to be modified and by how much.  Since most of us don't work with inertia formulas because they don't give us much in terms of practical solutions (how much should I change the SW or AR by to achieve my goal), it's not very useful.  I know some programs, like Gravagne's, give an inertia number but it's of little value other than curiosity for the nerds. (Last I checked Gravagne was also still using "downweight" which doesn't tease out the friction variability and thus is somewhat antiquated.)  That's especially true because the inertia in all pianos graduates from relatively high to relatively low from bottom to top of the scale since the hammers are always decreasing in mass and, generally, the AR is remaining constant, or fairly constant.  Because of that fact the Fandrich/Rhodes system used A4 as their target note for evaluation of the entire action.  Those same formulas (whatever it was that they used) would yield something quite different if a target was chosen higher or lower in the scale and would have to be modified accordingly.

------------------------------
David Love RPT
www.davidlovepianos.com
davidlovepianos@comcast.net
415 407 8320

Original Message:
Sent: 07-28-2023 12:34
From: David Love
Subject: Key ratio

To All

I still don't know what Chris is talking about. It makes no sense. Maybe someone else can explain it to me. There's no equivalence to the examples he gave. It's like asking for further explanation and having the person repeat what they said but louder. 

------------------------------
David Love RPT
www.davidlovepianos.com
davidlovepianos@comcast.net
415 407 8320

Original Message:
Sent: 07-28-2023 09:03
From: Chris Chernobieff
Subject: Key ratio

Its a public forum David, i didn't write it to you specifically in the first place.

I guess i should put "to all" from now on.

To all,

When a weight is being slid along a key to match a DW target or a FW target on a scale, it is equivalent to sliding a hammer along the shank to get a SW target. Both methods are/would be using leverage disadvantageously and at the cost of controlling the mass and inertia.

-chris

------------------------------
Chernobieff Piano Restorations
All the elements are known, and yet no combination there of creates life. Yet we are here.
865-986-7720 (text only please)

Original Message:
Sent: 07-28-2023 01:48
From: David Love
Subject: Key ratio

Chris

I read this 3+ times. I really tried. I even tried altering the 'em-PHA-sis on different syl-LA-bles. I still have no idea what you're talking about. But don't try again on my account, please. 

------------------------------
David Love RPT
www.davidlovepianos.com
davidlovepianos@comcast.net
415 407 8320

Original Message:
Sent: 07-28-2023 01:09
From: Chris Chernobieff
Subject: Key ratio

One problem with using FW as a measure. Lets say you have 10 keys with 2 leads each. because the hammer gets lights you have to slide them backwards so they have less effect. This is an admission a lighter weight would do the same thing.

That's just one way FW screws up inertia. 

Also, saying an action is light, medium, or heavy is not inertia control. Those are ballpark guesses that use terms that are relative. Its equivalent to saying that a weighted wheel will reach the bottom of a hill slowly, in due time, or quickly. Because i use inertia as a direct measure, i can say the weighted wheel will reach the bottom in 10 seconds. With that capability inertia can be communicated to others precisely, duplicated, and the smoothness across the compass controlled unlike what you can do with FW based systems.

-chris

-chris

------------------------------
Chernobieff Piano Restorations
All the elements are known, and yet no combination there of creates life. Yet we are here.
865-986-7720 (text only please)

Original Message:
Sent: 07-24-2023 13:06
From: David Love
Subject: Key ratio

David H

Sounds like a class not to be missed.  My beta testing is more to do with determining optimum hammer weight and then calculating a specific note for note weight curve based on the set you are choosing (rather than a somewhat predetermined "zone") and then the accompanying calculated FW curve to yield a specific BW that you choose.  From those numbers I can tell if you have an inertia problem or not (either too much or not enough).   It achieves that without having to measure action ratios at all, something most techs don't seem that comfortable with plus there's an inconsistency in measurement styles and what certain ARs mean in different methods. 

But once you have those two weight curves then where to place the leads (if you're starting from scratch which most of us aren't) is certainly in interesting topic.  It's been addressed in the past as it relates to key return (the accelerated action) but in spite of that slight benefit it's interesting to note that Steinway abandoned the more leads nearer the balance pin approach in favor of the 3-2-1-0 approach of the past.  

Interesting topic though.  Sorry I can't be there.  

------------------------------
David Love RPT
www.davidlovepianos.com
davidlovepianos@comcast.net
415 407 8320

Original Message:
Sent: 07-23-2023 07:45
From: David Hughes
Subject: Key ratio

Replying to David Love, message #12: I believe the two instructors are Dean Reyburn and some guy named Hughes something.

------------------------------
David Hughes RPT
Vintage Case Parts
Glyndon MD
(443) 522-2201

Original Message:
Sent: 07-23-2023 00:03
From: David Love
Subject: Key ratio

Thanks David. Who are the two instructors?  Not going, unfortunately

------------------------------
David Love RPT
www.davidlovepianos.com
davidlovepianos@comcast.net
415 407 8320

Original Message:
Sent: 07-21-2023 09:28
From: David Hughes
Subject: Key ratio

Everyone involved in this touchweight/key ratio/action ratio/inertia/momentum discussion might enjoy a class next week at our annual convention in Arlington, VA titled "Weigh-Off 101". I understand from the two instructors it will get deeper into these topics than merely a "101" approach, though all the basics will be covered, too. Some eye-opening examples of exactly where the lead can (should?) be placed along the length of the keystick will be included. Oh boy, I'll be in the front row!

David G. Hughes, RPT

Baltimore Chapter 

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David Hughes RPT
Vintage Case Parts
Glyndon MD
(443) 522-2201

Original Message:
Sent: 07-18-2023 10:57
From: Dave Conte
Subject: Key ratio

Question about key ratios. I am about to replace the angled capstans on a 95 year old Hamburg Steinway model M grand with straight WNG capstans. I find the straight line drifts 3 mm from the balance hole #1 at 117.5mm to 120.5mm at #88. The balance rail holes are located precisely the same distance from the back of the key at #1 and #88. Key ratio of the naturals from rep center to balance hole is 1:1.89 on #1 and 1:1.94 on #88. Could this be intentional or just a manufacturing error?

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Dave Conte, RPT

Piano Technician in Residence
The University of Tennessee
College of Music
Knoxville TN
(817) 307-5656
Owner: Rocky Top Piano
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