Pianotech

I have a 1970s Grotrian with not-original hammer heads. A pianist I am trying to please says it feels heavy. Sample notes show balance weight of 43, 44, and 40. Friction for these notes is 15, 14, and 12. There is very little lead in the keys.

I attempted a Stanwood New Action Protocol test. I added front weight on C4 to get it up to 27 grams, reducing its BW to 32. Strike weight was 10.1. I had to increase SW to 11.1 to get a BW of 38.

Having a C4 strike weight of 11.1 would make for a pretty heavy strike weight curve. Am I to conclude from this test that I should add weight to the hammers and then add weight to the keys to compensate and that will give me a medium inertial playing quality?

Am I missing something here?

------------------------------
John Pope
University of Kentucky School of Music
Lexington, KY
------------------------------

Hi John,

Back a little...   Your close to  having a kind of definition of what your client feels is a heavy action.  Quoting from my PTJournal article SNap Method part I :  "Specific combinations of front weight and balance weight are associated with particular inertial playing qualities" .   So you client says the action is heavy but you only have balance weight data for three sample notes. What are the front weights for those notes?  Please report.  

The solution will be reducing hammer weight and or ratio because BW + FW is an expression of Strike Weight times Ratio.

Also a 15 and 14 friction in the middle of the keyboard is a little high.  What's the cause of that?  Key easing?  Hammer Flange friction too high?  More investigation needed to establish the reason(s) for the percieved heaviness.   

Does this action have wippen assist springs?  If so you need to measure balance weight with them detached if you want to make sense of BS + FW.

I have a 1970s Grotrian with not-original hammer heads. A pianist I am trying to please says it feels heavy. Sample notes show balance weight of 43, 44, and 40. Friction for these notes is 15, 14, and 12. There is very little lead in the keys.

I attempted a Stanwood New Action Protocol test. I added front weight on C4 to get it up to 27 grams, reducing its BW to 32. Strike weight was 10.1. I had to increase SW to 11.1 to get a BW of 38.

Having a C4 strike weight of 11.1 would make for a pretty heavy strike weight curve. Am I to conclude from this test that I should add weight to the hammers and then add weight to the keys to compensate and that will give me a medium inertial playing quality?

Am I missing something here?

Thank you David.

My 3 sample notes: F3 BW 40.5, FW 29.4

C4 BW 43, FW 25.6

F4 BW 44.5, FW 23.4

And yes the front bushings are a bit tight. I can ease away some friction. Oddly, (to me) all notes in the piano have lead in both ends of the key, both sides of the balance rail. 

Hi John,

Back a little...   Your close to  having a kind of definition of what your client feels is a heavy action.  Quoting from my PTJournal article SNap Method part I :  "Specific combinations of front weight and balance weight are associated with particular inertial playing qualities" .   So you client says the action is heavy but you only have balance weight data for three sample notes. What are the front weights for those notes?  Please report.  

The solution will be reducing hammer weight and or ratio because BW + FW is an expression of Strike Weight times Ratio.

Also a 15 and 14 friction in the middle of the keyboard is a little high.  What's the cause of that?  Key easing?  Hammer Flange friction too high?  More investigation needed to establish the reason(s) for the percieved heaviness.   

Does this action have wippen assist springs?  If so you need to measure balance weight with them detached if you want to make sense of BS + FW.

I have a 1970s Grotrian with not-original hammer heads. A pianist I am trying to please says it feels heavy. Sample notes show balance weight of 43, 44, and 40. Friction for these notes is 15, 14, and 12. There is very little lead in the keys.

I attempted a Stanwood New Action Protocol test. I added front weight on C4 to get it up to 27 grams, reducing its BW to 32. Strike weight was 10.1. I had to increase SW to 11.1 to get a BW of 38.

Having a C4 strike weight of 11.1 would make for a pretty heavy strike weight curve. Am I to conclude from this test that I should add weight to the hammers and then add weight to the keys to compensate and that will give me a medium inertial playing quality?

Am I missing something here?

Thank you David.

My 3 sample notes: F3 BW 40.5, FW 29.4

C4 BW 43, FW 25.6

F4 BW 44.5, FW 23.4

And yes the front bushings are a bit tight. I can ease away some friction. Oddly, (to me) all notes in the piano have lead in both ends of the key, both sides of the balance rail. 

Hi John,

Back a little...   Your close to  having a kind of definition of what your client feels is a heavy action.  Quoting from my PTJournal article SNap Method part I :  "Specific combinations of front weight and balance weight are associated with particular inertial playing qualities" .   So you client says the action is heavy but you only have balance weight data for three sample notes. What are the front weights for those notes?  Please report.  

The solution will be reducing hammer weight and or ratio because BW + FW is an expression of Strike Weight times Ratio.

Also a 15 and 14 friction in the middle of the keyboard is a little high.  What's the cause of that?  Key easing?  Hammer Flange friction too high?  More investigation needed to establish the reason(s) for the percieved heaviness.   

Does this action have wippen assist springs?  If so you need to measure balance weight with them detached if you want to make sense of BS + FW.

I have a 1970s Grotrian with not-original hammer heads. A pianist I am trying to please says it feels heavy. Sample notes show balance weight of 43, 44, and 40. Friction for these notes is 15, 14, and 12. There is very little lead in the keys.

I attempted a Stanwood New Action Protocol test. I added front weight on C4 to get it up to 27 grams, reducing its BW to 32. Strike weight was 10.1. I had to increase SW to 11.1 to get a BW of 38.

Having a C4 strike weight of 11.1 would make for a pretty heavy strike weight curve. Am I to conclude from this test that I should add weight to the hammers and then add weight to the keys to compensate and that will give me a medium inertial playing quality?

Am I missing something here?

Interesting case.  Thanks always for sharing these great touchweight analysis tools with everyone David.

Just thinking...If this grand action was said to have key lead on both sides of the balance point on "all notes," and the described inertial playing quality is too firm/heavy, wouldn't it also be of immediate benefit to remove that lead from the rear portion of the keysticks, except where possibly reasonable in the upper high treble?  

Thank you David.

My 3 sample notes: F3 BW 40.5, FW 29.4

C4 BW 43, FW 25.6

F4 BW 44.5, FW 23.4

And yes the front bushings are a bit tight. I can ease away some friction. Oddly, (to me) all notes in the piano have lead in both ends of the key, both sides of the balance rail. 

Hi John,

Back a little...   Your close to  having a kind of definition of what your client feels is a heavy action.  Quoting from my PTJournal article SNap Method part I :  "Specific combinations of front weight and balance weight are associated with particular inertial playing qualities" .   So you client says the action is heavy but you only have balance weight data for three sample notes. What are the front weights for those notes?  Please report.  

The solution will be reducing hammer weight and or ratio because BW + FW is an expression of Strike Weight times Ratio.

Also a 15 and 14 friction in the middle of the keyboard is a little high.  What's the cause of that?  Key easing?  Hammer Flange friction too high?  More investigation needed to establish the reason(s) for the percieved heaviness.   

Does this action have wippen assist springs?  If so you need to measure balance weight with them detached if you want to make sense of BS + FW.

I have a 1970s Grotrian with not-original hammer heads. A pianist I am trying to please says it feels heavy. Sample notes show balance weight of 43, 44, and 40. Friction for these notes is 15, 14, and 12. There is very little lead in the keys.

I attempted a Stanwood New Action Protocol test. I added front weight on C4 to get it up to 27 grams, reducing its BW to 32. Strike weight was 10.1. I had to increase SW to 11.1 to get a BW of 38.

Having a C4 strike weight of 11.1 would make for a pretty heavy strike weight curve. Am I to conclude from this test that I should add weight to the hammers and then add weight to the keys to compensate and that will give me a medium inertial playing quality?

Am I missing something here?

Thank you Adrian for bringing this up.  Now I understand what John was saying about there being a lot of lead in the keys.  His C4 Front Weight is normal but there are leads in that back of the key too.  So that adds up to a lot of leads.  By all means remove the back leads, fill the holes with material of a similar density to the keystick stock and rebalance the front weights with weights on the front!

Interesting case.  Thanks always for sharing these great touchweight analysis tools with everyone David.

Just thinking...If this grand action was said to have key lead on both sides of the balance point on "all notes," and the described inertial playing quality is too firm/heavy, wouldn't it also be of immediate benefit to remove that lead from the rear portion of the keysticks, except where possibly reasonable in the upper high treble?  

Thank you David.

My 3 sample notes: F3 BW 40.5, FW 29.4

C4 BW 43, FW 25.6

F4 BW 44.5, FW 23.4

And yes the front bushings are a bit tight. I can ease away some friction. Oddly, (to me) all notes in the piano have lead in both ends of the key, both sides of the balance rail. 

Hi John,

Back a little...   Your close to  having a kind of definition of what your client feels is a heavy action.  Quoting from my PTJournal article SNap Method part I :  "Specific combinations of front weight and balance weight are associated with particular inertial playing qualities" .   So you client says the action is heavy but you only have balance weight data for three sample notes. What are the front weights for those notes?  Please report.  

The solution will be reducing hammer weight and or ratio because BW + FW is an expression of Strike Weight times Ratio.

Also a 15 and 14 friction in the middle of the keyboard is a little high.  What's the cause of that?  Key easing?  Hammer Flange friction too high?  More investigation needed to establish the reason(s) for the percieved heaviness.   

Does this action have wippen assist springs?  If so you need to measure balance weight with them detached if you want to make sense of BS + FW.

I have a 1970s Grotrian with not-original hammer heads. A pianist I am trying to please says it feels heavy. Sample notes show balance weight of 43, 44, and 40. Friction for these notes is 15, 14, and 12. There is very little lead in the keys.

I attempted a Stanwood New Action Protocol test. I added front weight on C4 to get it up to 27 grams, reducing its BW to 32. Strike weight was 10.1. I had to increase SW to 11.1 to get a BW of 38.

Having a C4 strike weight of 11.1 would make for a pretty heavy strike weight curve. Am I to conclude from this test that I should add weight to the hammers and then add weight to the keys to compensate and that will give me a medium inertial playing quality?

Am I missing something here?

Thank you Adrian for bringing this up.  Now I understand what John was saying about there being a lot of lead in the keys.  His C4 Front Weight is normal but there are leads in that back of the key too.  So that adds up to a lot of leads.  By all means remove the back leads, fill the holes with material of a similar density to the keystick stock and rebalance the front weights with weights on the front!

Interesting case.  Thanks always for sharing these great touchweight analysis tools with everyone David.

Just thinking...If this grand action was said to have key lead on both sides of the balance point on "all notes," and the described inertial playing quality is too firm/heavy, wouldn't it also be of immediate benefit to remove that lead from the rear portion of the keysticks, except where possibly reasonable in the upper high treble?  

Thank you David.

My 3 sample notes: F3 BW 40.5, FW 29.4

C4 BW 43, FW 25.6

F4 BW 44.5, FW 23.4

And yes the front bushings are a bit tight. I can ease away some friction. Oddly, (to me) all notes in the piano have lead in both ends of the key, both sides of the balance rail. 

Hi John,

Back a little...   Your close to  having a kind of definition of what your client feels is a heavy action.  Quoting from my PTJournal article SNap Method part I :  "Specific combinations of front weight and balance weight are associated with particular inertial playing qualities" .   So you client says the action is heavy but you only have balance weight data for three sample notes. What are the front weights for those notes?  Please report.  

The solution will be reducing hammer weight and or ratio because BW + FW is an expression of Strike Weight times Ratio.

Also a 15 and 14 friction in the middle of the keyboard is a little high.  What's the cause of that?  Key easing?  Hammer Flange friction too high?  More investigation needed to establish the reason(s) for the percieved heaviness.   

Does this action have wippen assist springs?  If so you need to measure balance weight with them detached if you want to make sense of BS + FW.

I have a 1970s Grotrian with not-original hammer heads. A pianist I am trying to please says it feels heavy. Sample notes show balance weight of 43, 44, and 40. Friction for these notes is 15, 14, and 12. There is very little lead in the keys.

I attempted a Stanwood New Action Protocol test. I added front weight on C4 to get it up to 27 grams, reducing its BW to 32. Strike weight was 10.1. I had to increase SW to 11.1 to get a BW of 38.

Having a C4 strike weight of 11.1 would make for a pretty heavy strike weight curve. Am I to conclude from this test that I should add weight to the hammers and then add weight to the keys to compensate and that will give me a medium inertial playing quality?

Am I missing something here?

Thank you Adrian for bringing this up.  Now I understand what John was saying about there being a lot of lead in the keys.  His C4 Front Weight is normal but there are leads in that back of the key too.  So that adds up to a lot of leads.  By all means remove the back leads, fill the holes with material of a similar density to the keystick stock and rebalance the front weights with weights on the front!

Interesting case.  Thanks always for sharing these great touchweight analysis tools with everyone David.

Just thinking...If this grand action was said to have key lead on both sides of the balance point on "all notes," and the described inertial playing quality is too firm/heavy, wouldn't it also be of immediate benefit to remove that lead from the rear portion of the keysticks, except where possibly reasonable in the upper high treble?  

Thank you David.

My 3 sample notes: F3 BW 40.5, FW 29.4

C4 BW 43, FW 25.6

F4 BW 44.5, FW 23.4

And yes the front bushings are a bit tight. I can ease away some friction. Oddly, (to me) all notes in the piano have lead in both ends of the key, both sides of the balance rail. 

Hi John,

Back a little...   Your close to  having a kind of definition of what your client feels is a heavy action.  Quoting from my PTJournal article SNap Method part I :  "Specific combinations of front weight and balance weight are associated with particular inertial playing qualities" .   So you client says the action is heavy but you only have balance weight data for three sample notes. What are the front weights for those notes?  Please report.  

The solution will be reducing hammer weight and or ratio because BW + FW is an expression of Strike Weight times Ratio.

Also a 15 and 14 friction in the middle of the keyboard is a little high.  What's the cause of that?  Key easing?  Hammer Flange friction too high?  More investigation needed to establish the reason(s) for the percieved heaviness.   

Does this action have wippen assist springs?  If so you need to measure balance weight with them detached if you want to make sense of BS + FW.

I have a 1970s Grotrian with not-original hammer heads. A pianist I am trying to please says it feels heavy. Sample notes show balance weight of 43, 44, and 40. Friction for these notes is 15, 14, and 12. There is very little lead in the keys.

I attempted a Stanwood New Action Protocol test. I added front weight on C4 to get it up to 27 grams, reducing its BW to 32. Strike weight was 10.1. I had to increase SW to 11.1 to get a BW of 38.

Having a C4 strike weight of 11.1 would make for a pretty heavy strike weight curve. Am I to conclude from this test that I should add weight to the hammers and then add weight to the keys to compensate and that will give me a medium inertial playing quality?

Am I missing something here?

Horace,   I greatly appreciate the value of your experience and wisdom.  Thank you for sharing.  

When you say "There is more to it than mass. Sadly, that's all that folks seem to be concentrating on these days." 

I see that there is a lot of interest on the mass of the hammer because we want to be able to grapple with its effects intelligently in our work to make  pianos as good as they can be.   The traditional down weight method just doesn't cut it.   Hammer weight is an foundational part of the puzzle. I also notice in all the very intelligent talk I read and hear about voicing hammers, hammer weight is seldom if ever mentioned.   I would be a lot happier to hear more discourse concerning all aspects of hammer weight.

Yours Truly,

Thank you David.

My 3 sample notes: F3 BW 40.5, FW 29.4

C4 BW 43, FW 25.6

F4 BW 44.5, FW 23.4

And yes the front bushings are a bit tight. I can ease away some friction. Oddly, (to me) all notes in the piano have lead in both ends of the key, both sides of the balance rail. 

Hi John,

Back a little...   Your close to  having a kind of definition of what your client feels is a heavy action.  Quoting from my PTJournal article SNap Method part I :  "Specific combinations of front weight and balance weight are associated with particular inertial playing qualities" .   So you client says the action is heavy but you only have balance weight data for three sample notes. What are the front weights for those notes?  Please report.  

The solution will be reducing hammer weight and or ratio because BW + FW is an expression of Strike Weight times Ratio.

Also a 15 and 14 friction in the middle of the keyboard is a little high.  What's the cause of that?  Key easing?  Hammer Flange friction too high?  More investigation needed to establish the reason(s) for the percieved heaviness.   

Does this action have wippen assist springs?  If so you need to measure balance weight with them detached if you want to make sense of BS + FW.

I have a 1970s Grotrian with not-original hammer heads. A pianist I am trying to please says it feels heavy. Sample notes show balance weight of 43, 44, and 40. Friction for these notes is 15, 14, and 12. There is very little lead in the keys.

I attempted a Stanwood New Action Protocol test. I added front weight on C4 to get it up to 27 grams, reducing its BW to 32. Strike weight was 10.1. I had to increase SW to 11.1 to get a BW of 38.

Having a C4 strike weight of 11.1 would make for a pretty heavy strike weight curve. Am I to conclude from this test that I should add weight to the hammers and then add weight to the keys to compensate and that will give me a medium inertial playing quality?

Am I missing something here?

Hi John,

Regarding  my comment: "So you client says the action is heavy but you only have balance weight data for three sample notes. What are the front weights for those notes?  Please report. "    Please clarify.  You posted: "C4 BW 43, FW 25.6".  Is this the condition the client commenting on as being heavy?

Thank you David.

My 3 sample notes: F3 BW 40.5, FW 29.4

C4 BW 43, FW 25.6

F4 BW 44.5, FW 23.4

And yes the front bushings are a bit tight. I can ease away some friction. Oddly, (to me) all notes in the piano have lead in both ends of the key, both sides of the balance rail. 

Hi John,

Back a little...   Your close to  having a kind of definition of what your client feels is a heavy action.  Quoting from my PTJournal article SNap Method part I :  "Specific combinations of front weight and balance weight are associated with particular inertial playing qualities" .   So you client says the action is heavy but you only have balance weight data for three sample notes. What are the front weights for those notes?  Please report.  

The solution will be reducing hammer weight and or ratio because BW + FW is an expression of Strike Weight times Ratio.

Also a 15 and 14 friction in the middle of the keyboard is a little high.  What's the cause of that?  Key easing?  Hammer Flange friction too high?  More investigation needed to establish the reason(s) for the percieved heaviness.   

Does this action have wippen assist springs?  If so you need to measure balance weight with them detached if you want to make sense of BS + FW.

I have a 1970s Grotrian with not-original hammer heads. A pianist I am trying to please says it feels heavy. Sample notes show balance weight of 43, 44, and 40. Friction for these notes is 15, 14, and 12. There is very little lead in the keys.

I attempted a Stanwood New Action Protocol test. I added front weight on C4 to get it up to 27 grams, reducing its BW to 32. Strike weight was 10.1. I had to increase SW to 11.1 to get a BW of 38.

Having a C4 strike weight of 11.1 would make for a pretty heavy strike weight curve. Am I to conclude from this test that I should add weight to the hammers and then add weight to the keys to compensate and that will give me a medium inertial playing quality?

Am I missing something here?

Sadly, i think all the acronyms, and the false positive  reading of measurement  that a balance based system is forced to use overly complicates the simple process that this really is. By the way, a unit of measure for inertia looks like this - kg x m².

Regardless, here's a simple procedure that works on every modern piano.

1)Fix all friction problems,

2)Make hammers in the Strike Weight Range #1 10.5g smoothly tapering to #88 5g. This means that A49 is about 8.5g.

3)Use a test key. I use #2, #3, #86 and #87 remove all lead. Put action stack back on.

4) Place your desired downweight on a key. Add lead until jack tender touches.  The rest of the keys are just fill.

5) Easy. Try a test key you'll see.

I use a system that measures the actual inertia of all 88 on my rebuilds so i get a more accurate lead placement in each key. But aim for leads far forward as possible to use as little as possible.

-chris

Hi John,

Regarding  my comment: "So you client says the action is heavy but you only have balance weight data for three sample notes. What are the front weights for those notes?  Please report. "    Please clarify.  You posted: "C4 BW 43, FW 25.6".  Is this the condition the client commenting on as being heavy?

Thank you David.

My 3 sample notes: F3 BW 40.5, FW 29.4

C4 BW 43, FW 25.6

F4 BW 44.5, FW 23.4

And yes the front bushings are a bit tight. I can ease away some friction. Oddly, (to me) all notes in the piano have lead in both ends of the key, both sides of the balance rail. 

Hi John,

Back a little...   Your close to  having a kind of definition of what your client feels is a heavy action.  Quoting from my PTJournal article SNap Method part I :  "Specific combinations of front weight and balance weight are associated with particular inertial playing qualities" .   So you client says the action is heavy but you only have balance weight data for three sample notes. What are the front weights for those notes?  Please report.  

The solution will be reducing hammer weight and or ratio because BW + FW is an expression of Strike Weight times Ratio.

Also a 15 and 14 friction in the middle of the keyboard is a little high.  What's the cause of that?  Key easing?  Hammer Flange friction too high?  More investigation needed to establish the reason(s) for the percieved heaviness.   

Does this action have wippen assist springs?  If so you need to measure balance weight with them detached if you want to make sense of BS + FW.

I have a 1970s Grotrian with not-original hammer heads. A pianist I am trying to please says it feels heavy. Sample notes show balance weight of 43, 44, and 40. Friction for these notes is 15, 14, and 12. There is very little lead in the keys.

I attempted a Stanwood New Action Protocol test. I added front weight on C4 to get it up to 27 grams, reducing its BW to 32. Strike weight was 10.1. I had to increase SW to 11.1 to get a BW of 38.

Having a C4 strike weight of 11.1 would make for a pretty heavy strike weight curve. Am I to conclude from this test that I should add weight to the hammers and then add weight to the keys to compensate and that will give me a medium inertial playing quality?

Am I missing something here?

I have a 1970s Grotrian with not-original hammer heads. A pianist I am trying to please says it feels heavy. Sample notes show balance weight of 43, 44, and 40. Friction for these notes is 15, 14, and 12. There is very little lead in the keys.

I attempted a Stanwood New Action Protocol test. I added front weight on C4 to get it up to 27 grams, reducing its BW to 32. Strike weight was 10.1. I had to increase SW to 11.1 to get a BW of 38.

Having a C4 strike weight of 11.1 would make for a pretty heavy strike weight curve. Am I to conclude from this test that I should add weight to the hammers and then add weight to the keys to compensate and that will give me a medium inertial playing quality?

Am I missing something here?

As DS says, not quite enough info.  However if you achieved a BW of 32 grams at C4 with a FW of 27 grams that would be a relatively low inertia action assuming that the SW at C4 is representative of the rest of the action.and falls within a reasonable SW curve (doesn't have to be an exact, existing zone).

Typically, for a medium inertia action you want a BW of 37 grams with FW of 24-25 grams at C4.  Your action if you adjusted the FW to achieve a BW of 37 grams would yield a FW of 22 grams.  Lower FWs that produce the same BW means that the inertia will be lower because the primary driver of inertia is the relationship between SW and AR.  And because the FW:BW relationship is 1:1 (inverse ratio) then modifications are simple and straight forward (don't worry about the wippen or the key for that matter).  If the inertia is too high, change either the AR or the SW to achieve the optimum BW:FW relationship.  No AR to caclulate or measure, no cute little gauges, just targets of FW and BW.  AR will determine the regulation specs, of course, and if that's your goal then you have to accept the limitations that puts on weight choices. 

BTW once you have established the required SW at C4 for the AR that is present in your system you can simply calculate your own curve on excel using a simple chart and a trendline curve (display equation on chart and note that you want a 2nd degree polynomial ax^2+bx+c, if you recall your high school algebra/geometry class.)  

The general procedure is to preset your FWs as about 80% of Stanwood FW maximums on several samples, say C1, C2, C3, C4, C5, C6, C7 C8 (more if you want). Then determine the SWs for each note that produces the BW that you want, say 37 grams.  Once you have that, put them into an excel spreadsheet, calculate your 2nd degree polynomial trendline curve and hit that curve as closely as possible.  

if you want a lower inertia action then set up your FWs at a lower percentage, say 75% or 70% and determine the SWs that hit that same BW target.   

However, they can also be responding to a DW that is too high in which case you will have to lower the BW.  The DW, recall, reflects the minimum force required to actuate the key with near zero acceleration,  While it's not something achieved in practice it can make a difference.  

If you're afraid of having to further lower the weight then attach a mini binder clip to the hammer end of the shank as part of establishing your SW target.  Then, if the customer still finds it heavy you can remove the .5 grams binder clip which will drop the BW by about 2.5 grams and in the process lower the inertia since you are removing  mass from the hammer lever.

If they still complain then refer them to your least favorite tech in the local chapter--just kidding, or course. 

My FW maximum curve is a little different than DS and looks like this.  Again the target should be around 80% for a 37g BW for a medium inetia action (IMO).  Lower FW for the same BW means lower inertia and vice versa.  BTW the FW max is most important in the lower 2/3s of the action.  The top end of the action will always have lower inertia than the bottom because the hammers are lighter (assuming uniform AR).  So if the set has you crossing into higher FW maximums in the upper end, I wouldn't worry about it.  Sometimes the makeup of the hammer set forces you to accept that.  Don't over complicate it, this is relatively easy stuff once you understand the relationships.  

(Note that DS's FW max is a bit lower at the upper end, about the same at the bottom.  This is a calculated curve BTW)

I have a 1970s Grotrian with not-original hammer heads. A pianist I am trying to please says it feels heavy. Sample notes show balance weight of 43, 44, and 40. Friction for these notes is 15, 14, and 12. There is very little lead in the keys.

I attempted a Stanwood New Action Protocol test. I added front weight on C4 to get it up to 27 grams, reducing its BW to 32. Strike weight was 10.1. I had to increase SW to 11.1 to get a BW of 38.

Having a C4 strike weight of 11.1 would make for a pretty heavy strike weight curve. Am I to conclude from this test that I should add weight to the hammers and then add weight to the keys to compensate and that will give me a medium inertial playing quality?

Am I missing something here?

Horace,

To your point about hammer makeup, etc. I just completed a Kawai GS-60 from the mid 80's. Long story short...when I replaced the original humongous hammers with Ronsen hammers felted with Bacon felt it instantly TRANSFORMED the entire personality of the instrument.  It became a gorgeous, lyrical and  singing beauty (previously it was "good" and powerful, but lacked any specific character). I was stunned by the instant change in voice. I had a similar experience on a Mason & Hamlin A. Exact same combination on that. (WNG shanks on both).

Peter Grey Piano Doctor 

As DS says, not quite enough info.  However if you achieved a BW of 32 grams at C4 with a FW of 27 grams that would be a relatively low inertia action assuming that the SW at C4 is representative of the rest of the action.and falls within a reasonable SW curve (doesn't have to be an exact, existing zone).

Typically, for a medium inertia action you want a BW of 37 grams with FW of 24-25 grams at C4.  Your action if you adjusted the FW to achieve a BW of 37 grams would yield a FW of 22 grams.  Lower FWs that produce the same BW means that the inertia will be lower because the primary driver of inertia is the relationship between SW and AR.  And because the FW:BW relationship is 1:1 (inverse ratio) then modifications are simple and straight forward (don't worry about the wippen or the key for that matter).  If the inertia is too high, change either the AR or the SW to achieve the optimum BW:FW relationship.  No AR to caclulate or measure, no cute little gauges, just targets of FW and BW.  AR will determine the regulation specs, of course, and if that's your goal then you have to accept the limitations that puts on weight choices. 

BTW once you have established the required SW at C4 for the AR that is present in your system you can simply calculate your own curve on excel using a simple chart and a trendline curve (display equation on chart and note that you want a 2nd degree polynomial ax^2+bx+c, if you recall your high school algebra/geometry class.)  

The general procedure is to preset your FWs as about 80% of Stanwood FW maximums on several samples, say C1, C2, C3, C4, C5, C6, C7 C8 (more if you want). Then determine the SWs for each note that produces the BW that you want, say 37 grams.  Once you have that, put them into an excel spreadsheet, calculate your 2nd degree polynomial trendline curve and hit that curve as closely as possible.  

if you want a lower inertia action then set up your FWs at a lower percentage, say 75% or 70% and determine the SWs that hit that same BW target.   

However, they can also be responding to a DW that is too high in which case you will have to lower the BW.  The DW, recall, reflects the minimum force required to actuate the key with near zero acceleration,  While it's not something achieved in practice it can make a difference.  

If you're afraid of having to further lower the weight then attach a mini binder clip to the hammer end of the shank as part of establishing your SW target.  Then, if the customer still finds it heavy you can remove the .5 grams binder clip which will drop the BW by about 2.5 grams and in the process lower the inertia since you are removing  mass from the hammer lever.

If they still complain then refer them to your least favorite tech in the local chapter--just kidding, or course. 

My FW maximum curve is a little different than DS and looks like this.  Again the target should be around 80% for a 37g BW for a medium inetia action (IMO).  Lower FW for the same BW means lower inertia and vice versa.  BTW the FW max is most important in the lower 2/3s of the action.  The top end of the action will always have lower inertia than the bottom because the hammers are lighter (assuming uniform AR).  So if the set has you crossing into higher FW maximums in the upper end, I wouldn't worry about it.  Sometimes the makeup of the hammer set forces you to accept that.  Don't over complicate it, this is relatively easy stuff once you understand the relationships.  

(Note that DS's FW max is a bit lower at the upper end, about the same at the bottom.  This is a calculated curve BTW)

I have a 1970s Grotrian with not-original hammer heads. A pianist I am trying to please says it feels heavy. Sample notes show balance weight of 43, 44, and 40. Friction for these notes is 15, 14, and 12. There is very little lead in the keys.

I attempted a Stanwood New Action Protocol test. I added front weight on C4 to get it up to 27 grams, reducing its BW to 32. Strike weight was 10.1. I had to increase SW to 11.1 to get a BW of 38.

Having a C4 strike weight of 11.1 would make for a pretty heavy strike weight curve. Am I to conclude from this test that I should add weight to the hammers and then add weight to the keys to compensate and that will give me a medium inertial playing quality?

Am I missing something here?

Well folks,

I'm back to the university shop this morning. As I walked in the thought occurred... "Did I tare the scale when I took those FW measurments yesterday?"

No, I did not. Here are the actual front weights

F3: FW 18.2, BW 40.5

C4 FW14.2,  BW43

F4 FW 12, BW 44.5

Horace,

To your point about hammer makeup, etc. I just completed a Kawai GS-60 from the mid 80's. Long story short...when I replaced the original humongous hammers with Ronsen hammers felted with Bacon felt it instantly TRANSFORMED the entire personality of the instrument.  It became a gorgeous, lyrical and  singing beauty (previously it was "good" and powerful, but lacked any specific character). I was stunned by the instant change in voice. I had a similar experience on a Mason & Hamlin A. Exact same combination on that. (WNG shanks on both).

Peter Grey Piano Doctor 

As DS says, not quite enough info.  However if you achieved a BW of 32 grams at C4 with a FW of 27 grams that would be a relatively low inertia action assuming that the SW at C4 is representative of the rest of the action.and falls within a reasonable SW curve (doesn't have to be an exact, existing zone).

Typically, for a medium inertia action you want a BW of 37 grams with FW of 24-25 grams at C4.  Your action if you adjusted the FW to achieve a BW of 37 grams would yield a FW of 22 grams.  Lower FWs that produce the same BW means that the inertia will be lower because the primary driver of inertia is the relationship between SW and AR.  And because the FW:BW relationship is 1:1 (inverse ratio) then modifications are simple and straight forward (don't worry about the wippen or the key for that matter).  If the inertia is too high, change either the AR or the SW to achieve the optimum BW:FW relationship.  No AR to caclulate or measure, no cute little gauges, just targets of FW and BW.  AR will determine the regulation specs, of course, and if that's your goal then you have to accept the limitations that puts on weight choices. 

BTW once you have established the required SW at C4 for the AR that is present in your system you can simply calculate your own curve on excel using a simple chart and a trendline curve (display equation on chart and note that you want a 2nd degree polynomial ax^2+bx+c, if you recall your high school algebra/geometry class.)  

The general procedure is to preset your FWs as about 80% of Stanwood FW maximums on several samples, say C1, C2, C3, C4, C5, C6, C7 C8 (more if you want). Then determine the SWs for each note that produces the BW that you want, say 37 grams.  Once you have that, put them into an excel spreadsheet, calculate your 2nd degree polynomial trendline curve and hit that curve as closely as possible.  

if you want a lower inertia action then set up your FWs at a lower percentage, say 75% or 70% and determine the SWs that hit that same BW target.   

However, they can also be responding to a DW that is too high in which case you will have to lower the BW.  The DW, recall, reflects the minimum force required to actuate the key with near zero acceleration,  While it's not something achieved in practice it can make a difference.  

If you're afraid of having to further lower the weight then attach a mini binder clip to the hammer end of the shank as part of establishing your SW target.  Then, if the customer still finds it heavy you can remove the .5 grams binder clip which will drop the BW by about 2.5 grams and in the process lower the inertia since you are removing  mass from the hammer lever.

If they still complain then refer them to your least favorite tech in the local chapter--just kidding, or course. 

My FW maximum curve is a little different than DS and looks like this.  Again the target should be around 80% for a 37g BW for a medium inetia action (IMO).  Lower FW for the same BW means lower inertia and vice versa.  BTW the FW max is most important in the lower 2/3s of the action.  The top end of the action will always have lower inertia than the bottom because the hammers are lighter (assuming uniform AR).  So if the set has you crossing into higher FW maximums in the upper end, I wouldn't worry about it.  Sometimes the makeup of the hammer set forces you to accept that.  Don't over complicate it, this is relatively easy stuff once you understand the relationships.  

(Note that DS's FW max is a bit lower at the upper end, about the same at the bottom.  This is a calculated curve BTW)

I have a 1970s Grotrian with not-original hammer heads. A pianist I am trying to please says it feels heavy. Sample notes show balance weight of 43, 44, and 40. Friction for these notes is 15, 14, and 12. There is very little lead in the keys.

I attempted a Stanwood New Action Protocol test. I added front weight on C4 to get it up to 27 grams, reducing its BW to 32. Strike weight was 10.1. I had to increase SW to 11.1 to get a BW of 38.

Having a C4 strike weight of 11.1 would make for a pretty heavy strike weight curve. Am I to conclude from this test that I should add weight to the hammers and then add weight to the keys to compensate and that will give me a medium inertial playing quality?

Am I missing something here?

The above measurements are what one of my piano profs experienced as heavy. When I played the piano I didn't experience it so much as heavy but definitely ...different.

Well folks,

I'm back to the university shop this morning. As I walked in the thought occurred... "Did I tare the scale when I took those FW measurments yesterday?"

No, I did not. Here are the actual front weights

F3: FW 18.2, BW 40.5

C4 FW14.2,  BW43

F4 FW 12, BW 44.5

Horace,

To your point about hammer makeup, etc. I just completed a Kawai GS-60 from the mid 80's. Long story short...when I replaced the original humongous hammers with Ronsen hammers felted with Bacon felt it instantly TRANSFORMED the entire personality of the instrument.  It became a gorgeous, lyrical and  singing beauty (previously it was "good" and powerful, but lacked any specific character). I was stunned by the instant change in voice. I had a similar experience on a Mason & Hamlin A. Exact same combination on that. (WNG shanks on both).

Peter Grey Piano Doctor 

As DS says, not quite enough info.  However if you achieved a BW of 32 grams at C4 with a FW of 27 grams that would be a relatively low inertia action assuming that the SW at C4 is representative of the rest of the action.and falls within a reasonable SW curve (doesn't have to be an exact, existing zone).

Typically, for a medium inertia action you want a BW of 37 grams with FW of 24-25 grams at C4.  Your action if you adjusted the FW to achieve a BW of 37 grams would yield a FW of 22 grams.  Lower FWs that produce the same BW means that the inertia will be lower because the primary driver of inertia is the relationship between SW and AR.  And because the FW:BW relationship is 1:1 (inverse ratio) then modifications are simple and straight forward (don't worry about the wippen or the key for that matter).  If the inertia is too high, change either the AR or the SW to achieve the optimum BW:FW relationship.  No AR to caclulate or measure, no cute little gauges, just targets of FW and BW.  AR will determine the regulation specs, of course, and if that's your goal then you have to accept the limitations that puts on weight choices. 

BTW once you have established the required SW at C4 for the AR that is present in your system you can simply calculate your own curve on excel using a simple chart and a trendline curve (display equation on chart and note that you want a 2nd degree polynomial ax^2+bx+c, if you recall your high school algebra/geometry class.)  

The general procedure is to preset your FWs as about 80% of Stanwood FW maximums on several samples, say C1, C2, C3, C4, C5, C6, C7 C8 (more if you want). Then determine the SWs for each note that produces the BW that you want, say 37 grams.  Once you have that, put them into an excel spreadsheet, calculate your 2nd degree polynomial trendline curve and hit that curve as closely as possible.  

if you want a lower inertia action then set up your FWs at a lower percentage, say 75% or 70% and determine the SWs that hit that same BW target.   

However, they can also be responding to a DW that is too high in which case you will have to lower the BW.  The DW, recall, reflects the minimum force required to actuate the key with near zero acceleration,  While it's not something achieved in practice it can make a difference.  

If you're afraid of having to further lower the weight then attach a mini binder clip to the hammer end of the shank as part of establishing your SW target.  Then, if the customer still finds it heavy you can remove the .5 grams binder clip which will drop the BW by about 2.5 grams and in the process lower the inertia since you are removing  mass from the hammer lever.

If they still complain then refer them to your least favorite tech in the local chapter--just kidding, or course. 

My FW maximum curve is a little different than DS and looks like this.  Again the target should be around 80% for a 37g BW for a medium inetia action (IMO).  Lower FW for the same BW means lower inertia and vice versa.  BTW the FW max is most important in the lower 2/3s of the action.  The top end of the action will always have lower inertia than the bottom because the hammers are lighter (assuming uniform AR).  So if the set has you crossing into higher FW maximums in the upper end, I wouldn't worry about it.  Sometimes the makeup of the hammer set forces you to accept that.  Don't over complicate it, this is relatively easy stuff once you understand the relationships.  

(Note that DS's FW max is a bit lower at the upper end, about the same at the bottom.  This is a calculated curve BTW)

I have a 1970s Grotrian with not-original hammer heads. A pianist I am trying to please says it feels heavy. Sample notes show balance weight of 43, 44, and 40. Friction for these notes is 15, 14, and 12. There is very little lead in the keys.

I attempted a Stanwood New Action Protocol test. I added front weight on C4 to get it up to 27 grams, reducing its BW to 32. Strike weight was 10.1. I had to increase SW to 11.1 to get a BW of 38.

Having a C4 strike weight of 11.1 would make for a pretty heavy strike weight curve. Am I to conclude from this test that I should add weight to the hammers and then add weight to the keys to compensate and that will give me a medium inertial playing quality?

Am I missing something here?

The above measurements are what one of my piano profs experienced as heavy. When I played the piano I didn't experience it so much as heavy but definitely ...different.

Well folks,

I'm back to the university shop this morning. As I walked in the thought occurred... "Did I tare the scale when I took those FW measurments yesterday?"

No, I did not. Here are the actual front weights

F3: FW 18.2, BW 40.5

C4 FW14.2,  BW43

F4 FW 12, BW 44.5

Horace,

To your point about hammer makeup, etc. I just completed a Kawai GS-60 from the mid 80's. Long story short...when I replaced the original humongous hammers with Ronsen hammers felted with Bacon felt it instantly TRANSFORMED the entire personality of the instrument.  It became a gorgeous, lyrical and  singing beauty (previously it was "good" and powerful, but lacked any specific character). I was stunned by the instant change in voice. I had a similar experience on a Mason & Hamlin A. Exact same combination on that. (WNG shanks on both).

Peter Grey Piano Doctor 

As DS says, not quite enough info.  However if you achieved a BW of 32 grams at C4 with a FW of 27 grams that would be a relatively low inertia action assuming that the SW at C4 is representative of the rest of the action.and falls within a reasonable SW curve (doesn't have to be an exact, existing zone).

Typically, for a medium inertia action you want a BW of 37 grams with FW of 24-25 grams at C4.  Your action if you adjusted the FW to achieve a BW of 37 grams would yield a FW of 22 grams.  Lower FWs that produce the same BW means that the inertia will be lower because the primary driver of inertia is the relationship between SW and AR.  And because the FW:BW relationship is 1:1 (inverse ratio) then modifications are simple and straight forward (don't worry about the wippen or the key for that matter).  If the inertia is too high, change either the AR or the SW to achieve the optimum BW:FW relationship.  No AR to caclulate or measure, no cute little gauges, just targets of FW and BW.  AR will determine the regulation specs, of course, and if that's your goal then you have to accept the limitations that puts on weight choices. 

BTW once you have established the required SW at C4 for the AR that is present in your system you can simply calculate your own curve on excel using a simple chart and a trendline curve (display equation on chart and note that you want a 2nd degree polynomial ax^2+bx+c, if you recall your high school algebra/geometry class.)  

The general procedure is to preset your FWs as about 80% of Stanwood FW maximums on several samples, say C1, C2, C3, C4, C5, C6, C7 C8 (more if you want). Then determine the SWs for each note that produces the BW that you want, say 37 grams.  Once you have that, put them into an excel spreadsheet, calculate your 2nd degree polynomial trendline curve and hit that curve as closely as possible.  

if you want a lower inertia action then set up your FWs at a lower percentage, say 75% or 70% and determine the SWs that hit that same BW target.   

However, they can also be responding to a DW that is too high in which case you will have to lower the BW.  The DW, recall, reflects the minimum force required to actuate the key with near zero acceleration,  While it's not something achieved in practice it can make a difference.  

If you're afraid of having to further lower the weight then attach a mini binder clip to the hammer end of the shank as part of establishing your SW target.  Then, if the customer still finds it heavy you can remove the .5 grams binder clip which will drop the BW by about 2.5 grams and in the process lower the inertia since you are removing  mass from the hammer lever.

If they still complain then refer them to your least favorite tech in the local chapter--just kidding, or course. 

My FW maximum curve is a little different than DS and looks like this.  Again the target should be around 80% for a 37g BW for a medium inetia action (IMO).  Lower FW for the same BW means lower inertia and vice versa.  BTW the FW max is most important in the lower 2/3s of the action.  The top end of the action will always have lower inertia than the bottom because the hammers are lighter (assuming uniform AR).  So if the set has you crossing into higher FW maximums in the upper end, I wouldn't worry about it.  Sometimes the makeup of the hammer set forces you to accept that.  Don't over complicate it, this is relatively easy stuff once you understand the relationships.  

(Note that DS's FW max is a bit lower at the upper end, about the same at the bottom.  This is a calculated curve BTW)

I have a 1970s Grotrian with not-original hammer heads. A pianist I am trying to please says it feels heavy. Sample notes show balance weight of 43, 44, and 40. Friction for these notes is 15, 14, and 12. There is very little lead in the keys.

I attempted a Stanwood New Action Protocol test. I added front weight on C4 to get it up to 27 grams, reducing its BW to 32. Strike weight was 10.1. I had to increase SW to 11.1 to get a BW of 38.

Having a C4 strike weight of 11.1 would make for a pretty heavy strike weight curve. Am I to conclude from this test that I should add weight to the hammers and then add weight to the keys to compensate and that will give me a medium inertial playing quality?

Am I missing something here?

The current hammers are Abels and look to have been glued onto existing shanks.

The above measurements are what one of my piano profs experienced as heavy. When I played the piano I didn't experience it so much as heavy but definitely ...different.

Well folks,

I'm back to the university shop this morning. As I walked in the thought occurred... "Did I tare the scale when I took those FW measurments yesterday?"

No, I did not. Here are the actual front weights

F3: FW 18.2, BW 40.5

C4 FW14.2,  BW43

F4 FW 12, BW 44.5

Horace,

To your point about hammer makeup, etc. I just completed a Kawai GS-60 from the mid 80's. Long story short...when I replaced the original humongous hammers with Ronsen hammers felted with Bacon felt it instantly TRANSFORMED the entire personality of the instrument.  It became a gorgeous, lyrical and  singing beauty (previously it was "good" and powerful, but lacked any specific character). I was stunned by the instant change in voice. I had a similar experience on a Mason & Hamlin A. Exact same combination on that. (WNG shanks on both).

Peter Grey Piano Doctor 

As DS says, not quite enough info.  However if you achieved a BW of 32 grams at C4 with a FW of 27 grams that would be a relatively low inertia action assuming that the SW at C4 is representative of the rest of the action.and falls within a reasonable SW curve (doesn't have to be an exact, existing zone).

Typically, for a medium inertia action you want a BW of 37 grams with FW of 24-25 grams at C4.  Your action if you adjusted the FW to achieve a BW of 37 grams would yield a FW of 22 grams.  Lower FWs that produce the same BW means that the inertia will be lower because the primary driver of inertia is the relationship between SW and AR.  And because the FW:BW relationship is 1:1 (inverse ratio) then modifications are simple and straight forward (don't worry about the wippen or the key for that matter).  If the inertia is too high, change either the AR or the SW to achieve the optimum BW:FW relationship.  No AR to caclulate or measure, no cute little gauges, just targets of FW and BW.  AR will determine the regulation specs, of course, and if that's your goal then you have to accept the limitations that puts on weight choices. 

BTW once you have established the required SW at C4 for the AR that is present in your system you can simply calculate your own curve on excel using a simple chart and a trendline curve (display equation on chart and note that you want a 2nd degree polynomial ax^2+bx+c, if you recall your high school algebra/geometry class.)  

The general procedure is to preset your FWs as about 80% of Stanwood FW maximums on several samples, say C1, C2, C3, C4, C5, C6, C7 C8 (more if you want). Then determine the SWs for each note that produces the BW that you want, say 37 grams.  Once you have that, put them into an excel spreadsheet, calculate your 2nd degree polynomial trendline curve and hit that curve as closely as possible.  

if you want a lower inertia action then set up your FWs at a lower percentage, say 75% or 70% and determine the SWs that hit that same BW target.   

However, they can also be responding to a DW that is too high in which case you will have to lower the BW.  The DW, recall, reflects the minimum force required to actuate the key with near zero acceleration,  While it's not something achieved in practice it can make a difference.  

If you're afraid of having to further lower the weight then attach a mini binder clip to the hammer end of the shank as part of establishing your SW target.  Then, if the customer still finds it heavy you can remove the .5 grams binder clip which will drop the BW by about 2.5 grams and in the process lower the inertia since you are removing  mass from the hammer lever.

If they still complain then refer them to your least favorite tech in the local chapter--just kidding, or course. 

My FW maximum curve is a little different than DS and looks like this.  Again the target should be around 80% for a 37g BW for a medium inetia action (IMO).  Lower FW for the same BW means lower inertia and vice versa.  BTW the FW max is most important in the lower 2/3s of the action.  The top end of the action will always have lower inertia than the bottom because the hammers are lighter (assuming uniform AR).  So if the set has you crossing into higher FW maximums in the upper end, I wouldn't worry about it.  Sometimes the makeup of the hammer set forces you to accept that.  Don't over complicate it, this is relatively easy stuff once you understand the relationships.  

(Note that DS's FW max is a bit lower at the upper end, about the same at the bottom.  This is a calculated curve BTW)

I have a 1970s Grotrian with not-original hammer heads. A pianist I am trying to please says it feels heavy. Sample notes show balance weight of 43, 44, and 40. Friction for these notes is 15, 14, and 12. There is very little lead in the keys.

I attempted a Stanwood New Action Protocol test. I added front weight on C4 to get it up to 27 grams, reducing its BW to 32. Strike weight was 10.1. I had to increase SW to 11.1 to get a BW of 38.

Having a C4 strike weight of 11.1 would make for a pretty heavy strike weight curve. Am I to conclude from this test that I should add weight to the hammers and then add weight to the keys to compensate and that will give me a medium inertial playing quality?

Am I missing something here?

More news. I neglected to notice that yes, we do have wippen assist springs. New balance weights figures coming soon

The current hammers are Abels and look to have been glued onto existing shanks.

The above measurements are what one of my piano profs experienced as heavy. When I played the piano I didn't experience it so much as heavy but definitely ...different.

Well folks,

I'm back to the university shop this morning. As I walked in the thought occurred... "Did I tare the scale when I took those FW measurments yesterday?"

No, I did not. Here are the actual front weights

F3: FW 18.2, BW 40.5

C4 FW14.2,  BW43

F4 FW 12, BW 44.5

Horace,

To your point about hammer makeup, etc. I just completed a Kawai GS-60 from the mid 80's. Long story short...when I replaced the original humongous hammers with Ronsen hammers felted with Bacon felt it instantly TRANSFORMED the entire personality of the instrument.  It became a gorgeous, lyrical and  singing beauty (previously it was "good" and powerful, but lacked any specific character). I was stunned by the instant change in voice. I had a similar experience on a Mason & Hamlin A. Exact same combination on that. (WNG shanks on both).

Peter Grey Piano Doctor 

As DS says, not quite enough info.  However if you achieved a BW of 32 grams at C4 with a FW of 27 grams that would be a relatively low inertia action assuming that the SW at C4 is representative of the rest of the action.and falls within a reasonable SW curve (doesn't have to be an exact, existing zone).

Typically, for a medium inertia action you want a BW of 37 grams with FW of 24-25 grams at C4.  Your action if you adjusted the FW to achieve a BW of 37 grams would yield a FW of 22 grams.  Lower FWs that produce the same BW means that the inertia will be lower because the primary driver of inertia is the relationship between SW and AR.  And because the FW:BW relationship is 1:1 (inverse ratio) then modifications are simple and straight forward (don't worry about the wippen or the key for that matter).  If the inertia is too high, change either the AR or the SW to achieve the optimum BW:FW relationship.  No AR to caclulate or measure, no cute little gauges, just targets of FW and BW.  AR will determine the regulation specs, of course, and if that's your goal then you have to accept the limitations that puts on weight choices. 

BTW once you have established the required SW at C4 for the AR that is present in your system you can simply calculate your own curve on excel using a simple chart and a trendline curve (display equation on chart and note that you want a 2nd degree polynomial ax^2+bx+c, if you recall your high school algebra/geometry class.)  

The general procedure is to preset your FWs as about 80% of Stanwood FW maximums on several samples, say C1, C2, C3, C4, C5, C6, C7 C8 (more if you want). Then determine the SWs for each note that produces the BW that you want, say 37 grams.  Once you have that, put them into an excel spreadsheet, calculate your 2nd degree polynomial trendline curve and hit that curve as closely as possible.  

if you want a lower inertia action then set up your FWs at a lower percentage, say 75% or 70% and determine the SWs that hit that same BW target.   

However, they can also be responding to a DW that is too high in which case you will have to lower the BW.  The DW, recall, reflects the minimum force required to actuate the key with near zero acceleration,  While it's not something achieved in practice it can make a difference.  

If you're afraid of having to further lower the weight then attach a mini binder clip to the hammer end of the shank as part of establishing your SW target.  Then, if the customer still finds it heavy you can remove the .5 grams binder clip which will drop the BW by about 2.5 grams and in the process lower the inertia since you are removing  mass from the hammer lever.

If they still complain then refer them to your least favorite tech in the local chapter--just kidding, or course. 

My FW maximum curve is a little different than DS and looks like this.  Again the target should be around 80% for a 37g BW for a medium inetia action (IMO).  Lower FW for the same BW means lower inertia and vice versa.  BTW the FW max is most important in the lower 2/3s of the action.  The top end of the action will always have lower inertia than the bottom because the hammers are lighter (assuming uniform AR).  So if the set has you crossing into higher FW maximums in the upper end, I wouldn't worry about it.  Sometimes the makeup of the hammer set forces you to accept that.  Don't over complicate it, this is relatively easy stuff once you understand the relationships.  

(Note that DS's FW max is a bit lower at the upper end, about the same at the bottom.  This is a calculated curve BTW)

I have a 1970s Grotrian with not-original hammer heads. A pianist I am trying to please says it feels heavy. Sample notes show balance weight of 43, 44, and 40. Friction for these notes is 15, 14, and 12. There is very little lead in the keys.

I attempted a Stanwood New Action Protocol test. I added front weight on C4 to get it up to 27 grams, reducing its BW to 32. Strike weight was 10.1. I had to increase SW to 11.1 to get a BW of 38.

Having a C4 strike weight of 11.1 would make for a pretty heavy strike weight curve. Am I to conclude from this test that I should add weight to the hammers and then add weight to the keys to compensate and that will give me a medium inertial playing quality?

Am I missing something here?

Balance Weight with wip springs disengaged

F3: BW 53 (FW 18.2)

C4: BW 54.5 (FW 43)

F4: BW 56  (FW 12)

More news. I neglected to notice that yes, we do have wippen assist springs. New balance weights figures coming soon

The current hammers are Abels and look to have been glued onto existing shanks.

The above measurements are what one of my piano profs experienced as heavy. When I played the piano I didn't experience it so much as heavy but definitely ...different.

Well folks,

I'm back to the university shop this morning. As I walked in the thought occurred... "Did I tare the scale when I took those FW measurments yesterday?"

No, I did not. Here are the actual front weights

F3: FW 18.2, BW 40.5

C4 FW14.2,  BW43

F4 FW 12, BW 44.5

Horace,

To your point about hammer makeup, etc. I just completed a Kawai GS-60 from the mid 80's. Long story short...when I replaced the original humongous hammers with Ronsen hammers felted with Bacon felt it instantly TRANSFORMED the entire personality of the instrument.  It became a gorgeous, lyrical and  singing beauty (previously it was "good" and powerful, but lacked any specific character). I was stunned by the instant change in voice. I had a similar experience on a Mason & Hamlin A. Exact same combination on that. (WNG shanks on both).

Peter Grey Piano Doctor 

As DS says, not quite enough info.  However if you achieved a BW of 32 grams at C4 with a FW of 27 grams that would be a relatively low inertia action assuming that the SW at C4 is representative of the rest of the action.and falls within a reasonable SW curve (doesn't have to be an exact, existing zone).

Typically, for a medium inertia action you want a BW of 37 grams with FW of 24-25 grams at C4.  Your action if you adjusted the FW to achieve a BW of 37 grams would yield a FW of 22 grams.  Lower FWs that produce the same BW means that the inertia will be lower because the primary driver of inertia is the relationship between SW and AR.  And because the FW:BW relationship is 1:1 (inverse ratio) then modifications are simple and straight forward (don't worry about the wippen or the key for that matter).  If the inertia is too high, change either the AR or the SW to achieve the optimum BW:FW relationship.  No AR to caclulate or measure, no cute little gauges, just targets of FW and BW.  AR will determine the regulation specs, of course, and if that's your goal then you have to accept the limitations that puts on weight choices. 

BTW once you have established the required SW at C4 for the AR that is present in your system you can simply calculate your own curve on excel using a simple chart and a trendline curve (display equation on chart and note that you want a 2nd degree polynomial ax^2+bx+c, if you recall your high school algebra/geometry class.)  

The general procedure is to preset your FWs as about 80% of Stanwood FW maximums on several samples, say C1, C2, C3, C4, C5, C6, C7 C8 (more if you want). Then determine the SWs for each note that produces the BW that you want, say 37 grams.  Once you have that, put them into an excel spreadsheet, calculate your 2nd degree polynomial trendline curve and hit that curve as closely as possible.  

if you want a lower inertia action then set up your FWs at a lower percentage, say 75% or 70% and determine the SWs that hit that same BW target.   

However, they can also be responding to a DW that is too high in which case you will have to lower the BW.  The DW, recall, reflects the minimum force required to actuate the key with near zero acceleration,  While it's not something achieved in practice it can make a difference.  

If you're afraid of having to further lower the weight then attach a mini binder clip to the hammer end of the shank as part of establishing your SW target.  Then, if the customer still finds it heavy you can remove the .5 grams binder clip which will drop the BW by about 2.5 grams and in the process lower the inertia since you are removing  mass from the hammer lever.

If they still complain then refer them to your least favorite tech in the local chapter--just kidding, or course. 

My FW maximum curve is a little different than DS and looks like this.  Again the target should be around 80% for a 37g BW for a medium inetia action (IMO).  Lower FW for the same BW means lower inertia and vice versa.  BTW the FW max is most important in the lower 2/3s of the action.  The top end of the action will always have lower inertia than the bottom because the hammers are lighter (assuming uniform AR).  So if the set has you crossing into higher FW maximums in the upper end, I wouldn't worry about it.  Sometimes the makeup of the hammer set forces you to accept that.  Don't over complicate it, this is relatively easy stuff once you understand the relationships.  

(Note that DS's FW max is a bit lower at the upper end, about the same at the bottom.  This is a calculated curve BTW)