Pianotech

This may be a hyper fussy question, but I am wondering if anyone takes the angle of the strings, from bridge to agraffes, into consideration when setting the hammer bore distance, in order to achieve a more accurate perpendicular hammer strike to the strings. I am using the center of the key bed at the balance rail to level the Steinway O from side to side and from front to back. I have leveled the piano by shimming the casters on the legs of the piano. So, with the key bed level, the strings have about a 1% or more downward angle, from bridge to front of piano. 

So, if the strings are angled down from front to back, then it makes theoretical sense to shorten the hammer bore distance a little bit, so that the hammer will travel just a little further in order to hit the string at a more perpendicular angle. 

Another way to ask this question is, "How important is a perfectly perpendicular hammer strike to tone production?  And is there a difference in tone quality if the hammer strikes a little before or a little after perpendicular?"

Thanks for putting up with my obsessiveness with this issue.

Joe

------------------------------
Joe Burros
Cell: 646-410-7174
jbcello@gmail.com
www.fmi-newengland.com
------------------------------

Joe Burros went:

Another way to ask this question is, "How important is a perfectly perpendicular hammer strike to tone production?  And is there a difference in tone quality if the hammer strikes a little before or a little after perpendicular?"

The importance of being the impact being "normal" is that when either the front or backside is looking for a way to lessen that impact (for instance, by using part of the impact force to lean either front or backwards), both sides will be balanced in their desire to make use of this "feint". This situation is like two people trying to get through a doorway wide enough only for one, and neither one give way to the other. The upshot of a non-normal impact by the hammer is a slight wiping motion as the hammer tilts, and a slight delay in the hammer felt's elastic reaction.

But feel free to get a small slip of of plexiglass, drill for and mount in that a thin drill bit (or other rod), draw a center line on a section-end hammer, and put the plexiglass over that hammer at strike and see directly how normal the contact is. I'd do this when gluing in section ends, while the glue is still wet enough to allow a correction for a normal impact. The section ends done, the remaining hammers in the section can have that same correction.

------------------------------
William Ballard RPT
WBPS
Saxtons River VT
802-869-9107

"Our lives contain a thousand springs
and dies if one be gone
Strange that a harp of a thousand strings
should keep in tune so long."
...........Dr. Watts, "The Continental Harmony,1774
------------------------------

Joe,

Yes. Always

Roger

------------------------------
Roger Gable RPT
Gable Piano
Everett WA
(425) 252-5000
------------------------------

Hi Roger, can you elaborate with some details about how you do this? That would be helpful to me. Thanks, Joe

------------------------------
Joe Burros
Cell: 646-410-7174
jbcello@gmail.com
www.fmi-newengland.com
------------------------------

Original Message:
Sent: 02-06-2024 19:38
From: Roger Gable
Subject: Does anyone adjust hammer bore distance to compensate for the string angle to acheive a perpendicular hammer strike?

Joe,

Yes. Always

Roger

------------------------------
Roger Gable RPT
Gable Piano
Everett WA
(425) 252-5000
------------------------------

Case in point.

Today I measured a Baldwin R from 1983 for hammer replacement. The hammershank center pins are 145mm above the keybed. The bass string height (1 - 26) is 202mm  so subtracting 145 from 202 gives me a desired bore distance of 57mm in the bass to have the shank level with the keybed and the hammer 90 degrees to the string at impact. The original bass hammers are bored at 57mm.

The string height in the two capo sections (54 - 88) is 192mm above the keybed. Again subtracting 145 from 192 gives me a desired bore distance of 47mm. The original hammers in the treble are bored at 47mm. So far so good, nothing to see here, move along.

But wait. The string height in the mid section is 194mm from the key bed. So all things being equal (unequal?) I would want to bore these hammers at 49mm. The originals are bored at 47mm.

All the hammers were bored at the factory with zero degrees of rake so the mid treble hammers were over centering from day one. Of course since the contact area of the current hammers is  roughly 20mm long it's hard to see exactly where the center really is.

So my options are:

1) Ignore the differences and duplicate what the factory did.............. not liking this one.

2) Add 1.5 degrees of positive rake to notes 27 - 53................... not thrilled about this either

3) Try and get my friends at the supply house to bore the middle section at 49mm.........probably the way I'll go if the hammer tails are long enough.

The point being that this piano has been perfectly serviceable for 40 years without a custom hammer bore. I'll try to improve it while I'm working on it because I can and because it'll make the job more fun. At the end of the day though, no-one but me will know or care.

 I'm okay with that.

------------------------------
Karl Roeder
Pompano Beach FL
------------------------------

Original Message:
Sent: 02-06-2024 19:41
From: Joseph Burros
Subject: Does anyone adjust hammer bore distance to compensate for the string angle to acheive a perpendicular hammer strike?

Hi Roger, can you elaborate with some details about how you do this? That would be helpful to me. Thanks, Joe

------------------------------
Joe Burros
Cell: 646-410-7174
jbcello@gmail.com
www.fmi-newengland.com
------------------------------


Original Message:
Sent: 02-06-2024 19:38
From: Roger Gable
Subject: Does anyone adjust hammer bore distance to compensate for the string angle to acheive a perpendicular hammer strike?

Joe,

Yes. Always

Roger

------------------------------
Roger Gable RPT
Gable Piano
Everett WA
(425) 252-5000

We at Brooks LTD .. have done/ and are open to custom boring to accommodate this for these types of situations when giving detailed information.  

------------------------------
Melanie Brooks
Brooks, Ltd. Piano Products LLC
Uncasville CT
(860) 848-6605
------------------------------

Original Message:
Sent: 02-07-2024 18:38
From: Karl Roeder
Subject: Does anyone adjust hammer bore distance to compensate for the string angle to acheive a perpendicular hammer strike?

Case in point.

Today I measured a Baldwin R from 1983 for hammer replacement. The hammershank center pins are 145mm above the keybed. The bass string height (1 - 26) is 202mm  so subtracting 145 from 202 gives me a desired bore distance of 57mm in the bass to have the shank level with the keybed and the hammer 90 degrees to the string at impact. The original bass hammers are bored at 57mm.

The string height in the two capo sections (54 - 88) is 192mm above the keybed. Again subtracting 145 from 192 gives me a desired bore distance of 47mm. The original hammers in the treble are bored at 47mm. So far so good, nothing to see here, move along.

But wait. The string height in the mid section is 194mm from the key bed. So all things being equal (unequal?) I would want to bore these hammers at 49mm. The originals are bored at 47mm.

All the hammers were bored at the factory with zero degrees of rake so the mid treble hammers were over centering from day one. Of course since the contact area of the current hammers is  roughly 20mm long it's hard to see exactly where the center really is.

So my options are:

1) Ignore the differences and duplicate what the factory did.............. not liking this one.

2) Add 1.5 degrees of positive rake to notes 27 - 53................... not thrilled about this either

3) Try and get my friends at the supply house to bore the middle section at 49mm.........probably the way I'll go if the hammer tails are long enough.

The point being that this piano has been perfectly serviceable for 40 years without a custom hammer bore. I'll try to improve it while I'm working on it because I can and because it'll make the job more fun. At the end of the day though, no-one but me will know or care.

 I'm okay with that.

------------------------------
Karl Roeder
Pompano Beach FL
------------------------------


Original Message:
Sent: 02-06-2024 19:41
From: Joseph Burros
Subject: Does anyone adjust hammer bore distance to compensate for the string angle to acheive a perpendicular hammer strike?

Hi Roger, can you elaborate with some details about how you do this? That would be helpful to me. Thanks, Joe

------------------------------
Joe Burros
Cell: 646-410-7174
jbcello@gmail.com
www.fmi-newengland.com


Original Message:
Sent: 02-06-2024 19:38
From: Roger Gable
Subject: Does anyone adjust hammer bore distance to compensate for the string angle to acheive a perpendicular hammer strike?

Joe,

Yes. Always

Roger

------------------------------
Roger Gable RPT
Gable Piano
Everett WA
(425) 252-5000

Mr. Burros,

In general manufacturers have altered the fore and aft bore angle to get the hammer at 90 degrees to the string at contact. In the case of your Steinway model O, the bigger variable will be the string height from section to section and even within a section due to the plate having been cast with a crowned string plane in mind. I have observed a 2mm difference in string height between notes 27 and 54 on a model O. Some techs will customize the bore distance so that the hammershank is at the same angle (preferably parallel to the keybed) on every note when the hammer contacts the string. This in order to make the regulation more uniform. The more common practice is to compensate with slightly different touch depth note to note with uniform aftertouch being prioritized.

In the real world; I have seen some great pianos with hammers badly over centering or under centering. Conversely I have seen some awful instruments that were set to very precise regulation and contact profiles.

My two cents: Use better hammers and action parts, pay attention to the string terminations and mind how the soundboard is loaded.

Better minds with more experience will have better suggestions.

------------------------------
Karl Roeder
Pompano Beach FL
------------------------------

Joe,
Your string angle may also change if you measure in a different season. In high humidity, the sound board/bridges very often raise the string height slightly, and lower it in low humidity. That’s why dry conditions may sometimes have hammers blocking when regulated tightly in high humidity. Your keybed will also change shape in different seasons.

It’s all poison, pick yours.

Joe Wiencek
NYC


Original Message:
Sent: 2/6/2024 7:51:00 PM
From: Karl Roeder
Subject: RE: Does anyone adjust hammer bore distance to compensate for the string angle to acheive a perpendicular hammer strike?

Mr. Burros,

In general manufacturers have altered the fore and aft bore angle to get the hammer at 90 degrees to the string at contact. In the case of your Steinway model O, the bigger variable will be the string height from section to section and even within a section due to the plate having been cast with a crowned string plane in mind. I have observed a 2mm difference in string height between notes 27 and 54 on a model O. Some techs will customize the bore distance so that the hammershank is at the same angle (preferably parallel to the keybed) on every note when the hammer contacts the string. This in order to make the regulation more uniform. The more common practice is to compensate with slightly different touch depth note to note with uniform aftertouch being prioritized.

In the real world; I have seen some great pianos with hammers badly over centering or under centering. Conversely I have seen some awful instruments that were set to very precise regulation and contact profiles.

My two cents: Use better hammers and action parts, pay attention to the string terminations and mind how the soundboard is loaded.

Better minds with more experience will have better suggestions.

------------------------------
Karl Roeder
Pompano Beach FL
------------------------------

You can, or you can adjust the rake by one degree, or you can do nothing and the hammer will marginally under center until it wears a little bit and then it will be perpendicular and then when it wears a bit more it will over center. 

I don't make any compensation. Have you actually calculated how much you would have to shorten the bore for 1 degrees?  You might do that.  It's probably within the margin of error in hammer boring not to mention the slight variation in string height across the scale. 

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

I wouldn't worry about it unless you had noticed specific tonal issues prior to teardown that you could realistically trace to that source. If for instance you has "nothing" on the last three notes abd wondered why, and then you ultimately discovered this aberration, then you might consider efforts to ameliorate the problem. But if it sounded "normal", or even pretty darn good up there, I would leave well enough alone. 

Peter Grey Piano Doctor 

------------------------------
Peter Grey
Stratham NH
(603) 686-2395
pianodoctor57@gmail.com
------------------------------

Original Message:
Sent: 02-07-2024 02:13
From: David Love
Subject: Does anyone adjust hammer bore distance to compensate for the string angle to acheive a perpendicular hammer strike?

You can, or you can adjust the rake by one degree, or you can do nothing and the hammer will marginally under center until it wears a little bit and then it will be perpendicular and then when it wears a bit more it will over center. 

I don't make any compensation. Have you actually calculated how much you would have to shorten the bore for 1 degrees?  You might do that.  It's probably within the margin of error in hammer boring not to mention the slight variation in string height across the scale. 

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

Many thanks for all your comments that help me determine how to proceed, and bring up issues that might not have occurred to me. I will take all your suggestions and use them to come up with a solution that goes for the most accurate strike point/position, but not take too much time and fuss over this issue. My big take away from all the comments is that not one person has noticed that there is any improvement or difference in tone production that result from very minute differences in strike point angle. 

This may be an interesting area in which to do some experimenting in the future. It would be interesting to somehow be able to change the rake angles on the same hammer and string to see if there are any differences in tone quality between the different settings.

------------------------------
Joe Burros
Cell: 646-410-7174
jbcello@gmail.com
www.fmi-newengland.com
------------------------------

Original Message:
Sent: 02-07-2024 21:58
From: Peter Grey
Subject: Does anyone adjust hammer bore distance to compensate for the string angle to acheive a perpendicular hammer strike?

I wouldn't worry about it unless you had noticed specific tonal issues prior to teardown that you could realistically trace to that source. If for instance you has "nothing" on the last three notes abd wondered why, and then you ultimately discovered this aberration, then you might consider efforts to ameliorate the problem. But if it sounded "normal", or even pretty darn good up there, I would leave well enough alone. 

Peter Grey Piano Doctor 

------------------------------
Peter Grey
Stratham NH
(603) 686-2395
pianodoctor57@gmail.com
------------------------------


Original Message:
Sent: 02-07-2024 02:13
From: David Love
Subject: Does anyone adjust hammer bore distance to compensate for the string angle to acheive a perpendicular hammer strike?

You can, or you can adjust the rake by one degree, or you can do nothing and the hammer will marginally under center until it wears a little bit and then it will be perpendicular and then when it wears a bit more it will over center. 

I don't make any compensation. Have you actually calculated how much you would have to shorten the bore for 1 degrees?  You might do that.  It's probably within the margin of error in hammer boring not to mention the slight variation in string height across the scale. 

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

Mr. Burros,

I use a machinist or drafters square, or similar, to measure from the plane of the strings to project down into the action cavity with a "dummy" shank and a glued 90-degree piece of wood that simulates the hammer plus a little extra length. Bring the dummy shank/hammer assembly up to the strike position cutting off the required material until your square lines up parallel to your dummy hammer. This assures your 90-degree hammer and assumes your shank will be parallel to the strings upon contact. The parallel string to shank assumption could be wrong with some pianos where the height of the bass string section is so high you can't bore your hammer at a 90-degree angle. If you did, the bore-distance would be so long that you couldn't get the action in and out of the piano. Yamaha is famous for that. The over-travel of the bass section shanks (shank not parallel to the string upon contact) is a compromise Yamaha has made to assure a 90-degree hammer at strike.

------------------------------
Roger Gable RPT
Gable Piano
Everett WA
(425) 252-5000
------------------------------

Original Message:
Sent: 02-08-2024 12:25
From: Joseph Burros
Subject: Does anyone adjust hammer bore distance to compensate for the string angle to acheive a perpendicular hammer strike?

Many thanks for all your comments that help me determine how to proceed, and bring up issues that might not have occurred to me. I will take all your suggestions and use them to come up with a solution that goes for the most accurate strike point/position, but not take too much time and fuss over this issue. My big take away from all the comments is that not one person has noticed that there is any improvement or difference in tone production that result from very minute differences in strike point angle. 

This may be an interesting area in which to do some experimenting in the future. It would be interesting to somehow be able to change the rake angles on the same hammer and string to see if there are any differences in tone quality between the different settings.

------------------------------
Joe Burros
Cell: 646-410-7174
jbcello@gmail.com
www.fmi-newengland.com
------------------------------


Original Message:
Sent: 02-07-2024 21:58
From: Peter Grey
Subject: Does anyone adjust hammer bore distance to compensate for the string angle to acheive a perpendicular hammer strike?

I wouldn't worry about it unless you had noticed specific tonal issues prior to teardown that you could realistically trace to that source. If for instance you has "nothing" on the last three notes abd wondered why, and then you ultimately discovered this aberration, then you might consider efforts to ameliorate the problem. But if it sounded "normal", or even pretty darn good up there, I would leave well enough alone. 

Peter Grey Piano Doctor 

------------------------------
Peter Grey
Stratham NH
(603) 686-2395
pianodoctor57@gmail.com


Original Message:
Sent: 02-07-2024 02:13
From: David Love
Subject: Does anyone adjust hammer bore distance to compensate for the string angle to acheive a perpendicular hammer strike?

You can, or you can adjust the rake by one degree, or you can do nothing and the hammer will marginally under center until it wears a little bit and then it will be perpendicular and then when it wears a bit more it will over center. 

I don't make any compensation. Have you actually calculated how much you would have to shorten the bore for 1 degrees?  You might do that.  It's probably within the margin of error in hammer boring not to mention the slight variation in string height across the scale. 

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