Spring Rail Rebuilding

[Ken Jankura]

Terry,
   I taught a mini-tech on replacing hammer return springs at the PA State
Conference last April, and I spent part of the class talking about the
effect of hammer return spring tension on touchweight in a vertical action.
On a Sohmer console action model, I was able to make a 17 gram difference in
downweight by changing the shape (tension) of the spring. I was only able to
change the downweight by about 6 grams by changing hammer #88 for hammer #1,
and only 6 grams or so by changing the flange center pin friction from 'one
swing' to 'perpetual motion machine'.
So, I don't think persuing heavier or lighter gauge springs makes any sense,
and yes, just try to adjust them evenly. Experiment around with it, you'll
be amazed.
An offshoot of this is that I think when replacing upright hammers, bigger
is better tonally and won't adversely affect touchweight much at all. Just
don't go and reweight the keys by mistake because your springs are set too
strong.
Ken Jankura
Newburg, PA

----- Original Message -----
From: "Farrell" <mfarrel2@tampabay.rr.com>
To: <pianotech@ptg.org>
Sent: Thursday, September 20, 2001 12:06 PM
Subject: Re: Spring Rail Rebuilding


> Schaff offers medium and heavy hammer butt springs. I measured their
> diameters and the medium is 0.022" and the heavy is 0.024". The original
> springs measure out to be 0.020". Does anyone know a source of "light"
> upright hammer butt springs? If not, I suppose the mediums will work fine,
> I'll  just adjust them accordingly.
>
> Terry Farrell
>
> >
>