balancing action heresy?

[David Ilvedson]

No assist springs on this piano...

I have ended up going through and evening the hammer weights, adding an average of .6 grams or so and I'll do the usual Stanwood stuff of DW + UP/2=BW and add or subtract from the FW.   I went into this to get an understanding of the process so I might as well do it...I had a weak moment last night...;-]

That was the way I always weighed off actions in the past...DW but I was conscious of UP and strived to get as least 20 + grams.   

David Ilvedson, RPT
Pacifica, CA  94044


----- Original message ----------------------------------------
From: "Ric Brekne" <ricbrek at broadpark.no>
To: pianotech at ptg.org
Received: 9/5/2006 8:35:33 AM
Subject: balancing action heresy?


>Hi David

>There are several weighs (grin) to approach the whole thing.  Nothing 
>perse tells us we have to follow a distinct curve in the first place.. 
>One can even opt for a big shift in weights from bass to tenor to create 
>a kind of register change affect if you want. The point is the whats on 
>one side of the lever must be balanced one way or another on the other side.

>To your specific question. Remember that the origional action was 
>balanced the old way. I suppose we are still talking about your old 
>Bechstein E ?.  In anycase its likely they had the hammers mounted and 
>the action nicely regulated before doing the weighoff.  A 50 gram (or 
>close to that weight) is placed on the end of the keys and a leads are 
>placed down the length of the key to ascertain when the key will start 
>to drop.  You probably already know this... I just like telling 
>stories.. :)  Ok.. so remembering that, the action was at one time 
>balanced .. no friction discrepencies are accounted for in this method.. 
>nor any ratio variances key to key. Pure static as is downweight. 
>Upweight was generally not even considered further then a minimum lift.  
>Balance weight was... well it didnt exist in most minds. Not an issue at 
>the least.

>Ok.. so you are looking at a previoiusly balanced action... and you are 
>doing some evening out of hammer strikeweights... these are new hammers 
>??.  If this is a high quality instrument... like your E once was... a 
>lot of care was taken even back then to do things that created an even 
>touch. Taking hammer dead weight was by no means unheard of.  
>Speculation here of course... but it could be easily be that the 
>origional hammers had a weight specification that is close to what you 
>are employing now.  This happens of course... not unfrequently either 
>really.  Even in lesser quality instruments for that matter. But I 
>wouldnt count on it happening every time ... nor even in the majority of 
>times. We hear from time to time from some distraught young one whoes 
>just put on a new set of hammers and wonders why everything is suddenly 
>so heavy :)

>The nice thing about Stanwood is that if you do all the measurements 
>ahead of time... then you KNOW what the result is going to be before you 
>actually start putting things together.

>One other point... since it seems you have assist springs. You should of 
>course make all measurements with any whippen assist springs 
>de-tached... and you should'nt really hook em back up until all else is 
>finished. 

>Cheers
>RicB



>-------

>Granted I am a Stanwood novice:

>But while I am going through and adding lead to the hammers, I'm finding 
>if instead of evening out the hammer weight exactly to the curve and I 
>deviate slightly from the curve...actually I am only evening out the 
>hammer weights...not following a curve...YIKES...as I was saying, I can 
>get my upweight and downweight in the generally right spot although the 
>BW is not exact...but pretty close.   In other words I'm not having to 
>deal with the key weights at all...at least on this action...Bechstein...

>So am I to be burned at the stake?   I realize any differences in hammer 
>weight will translate into slightly difference spring tensions and that 
>is a trade off...what else am I missing...

>Please David S...don't send anyone from Callahan's to knock me off...;-]   

>This is all in the beginning stages, so If I'm screwing up royally I can 
>back off...

>David Ilvedson, RPT
>Pacifica, CA 94044

>heresy