Steinway action noise

[David Ilvedson]

Less bad is always better...

David Ilvedson, RPT
Pacifica, CA  94044

----- Original message ----------------------------------------
From: "Greg Newell" <gnewell at ameritech.net>
To: "Pianotech List" <pianotech at ptg.org>
Received: 11/25/2007 6:19:14 PM
Subject: RE: Steinway action noise


>Ric,	
>	First, thank you for your interest in my customers dilemma. I at
>least recognize that it's their problem and not mine. That's a good thing.
>Secondly you have on a few occasions mentioned the desire to obtain the old
>parts. Oh that that were possible. They and the technician who did the
>previous work are gone I'm told. It will take me a while to digest what
>you've written but the short version is that I'm aware that there will be
>some complications however, 1) it will be a good learning experience 2) I'm
>not likely to proceeed further than what they are willing to pay for and 3)
>I have no choice but to proceed in some fashion to make this .... less bad.
>Thanks again for the efforts.

>-----Original Message-----
>From: pianotech-bounces at ptg.org [mailto:pianotech-bounces at ptg.org] On Behalf
>Of Richard Brekne
>Sent: Sunday, November 25, 2007 4:12 PM
>To: pianotech at ptg.org
>Subject: Steinway action noise

>Hi Greg

>I was curious as to what is happening with your troubled action.  I got 
>asked to defend my skepticism to moving the whippen flange out in the 
>case your original  hammer flanges had their center pin holes 1 mm 
>closer in to the flange mounting screw.  I havent had time until now to 
>put out some rough numbers but here goes.. and perhaps you will see why 
>I opt for trying to just keep the old flanges in this situation.

>To begin with, if you have hammer flange centers 1 mm distal from 
>originals and paper your whippen flange 1 mm out to match then all you 
>have done is basically to move the stack distal 1 mm and the hammers 
>inwards 1 mm to keep the same strike line. Thats where a large portion 
>of whatever change in ratio will occur.

>I'll give a simplified example. Start with a say 5.25 ratio comprised of 
>a 7.0 shank ratio, 1.5 whippen ratio and 0.5 key ratio.
>Assume also the following parameters.

>Hammer center moulding to center pin 136 mm
>Bore length 48 mm
>Knuckle core to center pin 16 mm
>Whippen center to cushion/capstan contact 62 mm
>Whippen center straight up to the contact point of the jacktop /knuckle 
>93 mm

>This is all basically following Overs way of measuring the ratio.  
>Yeilds an hammer shank long moment arm of about 144.34 and a short 
>moment arm of 20.62

>Now if you just move out the whippen and shank flanges distal 1 mm and 
>the hammers in 1 mm to keep the strike line...then the shank ratio drops 
>to about 6.954 from 7.0 In addition the whippens ratio changes 
>slightly.  The long arm is typically about around 30 degrees out from 
>the horizontal line from the whippen center and the lower arm about 
>18-20 degrees. This means a horizontal move of the whippen flange center 
>will lengthen the upper arm slightly more then the move will add to the 
>lower arm.  Using 18 and 30 degrees the moment ratio drops to 1.4933   
>The new total action ratio is then 5.19.  (6.954*1.4933*.5)

>Using the same calcs if you've installed 17 mm knuckle length and move 
>the whippen flange out 1 mm more to keep the jack on the parallel with 
>the knuckle core the whippen ratio drops to around 1.487 and the hammer 
>shank ratio changes to 6.72 which gives 6.72*1.487*0.5 = 5.0 for the new 
>total ratio.  Thats beginning to be a significant drop.

>In itself not necessarily a bad thing... but there is another situation 
>going on here I am less comfortable with.  A distal horizontal move of 
>the whippen flange center also changes the effective travel of the jack 
>tip fairly significantly.  In the above example you are roughly 58 mm 
>straight out from the whippen flange center to the point on the lower 
>arm directly above the whippen cushion / capstan point. If the key moves 
>that say 5 mm upwards, then a jack tip that is 120 mm away from the 
>flange center will move about 10.3 mm. (of course the jack tender will 
>get in the way but I'll get to that.) With a 2 mm distal move of the 
>whippen flange center jack tip rise is reduced to 10 mm. The jack itself 
>is a roughly 2:1 ratio lever so the jack top will move twice as much as 
>the tip.  Since it comes into play about 80 mm into key dip you are 
>looking roughly at a 0.5 mm reduction in jack top travel.

>None of this even gets into the fact that with a move of the flange 
>center by itself (as in the case of compensating for the 16 to 17 mm 
>knuckle distance difference) requires you to lower the capstan so as to 
>get the same blow distance... which again changes the jack angle 
>slightly outwards. In reality, going from 16 to 17 mm knuckle difference 
>requires a bit more of a 1 mm  distal move of the whippen flange center 
>to maintain both the same blow distance and the jack being on line with 
>the knuckle core. At the same time it reduces jack travel slightly... 
>enough to have an impact on letoff and drop timing.  To maintain 
>simultaneous contact you will have to lower the let off button. But the 
>jack wont come out from under the knuckle quite as far (key dip staying 
>the same).

>There is more one could get into here if one wanted to...such as jack 
>stop cushions (both for and aft)...etc,  but I think this all sort of 
>explains why I prefer to stick with the original hammer shank flanges 
>instead of papering the whippens out.

>On the other hand... if the whippens were too close in to begin with... 
>well thats another matter.

>Hope this clarifies somewhat... sorry about the length but even general 
>numbers force a bit of explanation

>Cheers
>RicB