[pianotech] return spring

[Tom Driscoll]

I don't mean to sound like a Luddite here , but my example went like 
this. :

"Tom the unacorda pedal is too hard to depress. "

I called Kent at steinway and he advised to straighten the spring out 
with a hammer as I descibed earlier in this thread.
After a couple of judicious whacks the spring was reinstalled :

  " Tom ,that's great. much easier to depress"

This was in the context of a full regulation on this "B" so yes the bed 
,frame , spring  etc down to the pedal had been cleaned-lubed.
As mentioned this was several years ago and  it has been a stable 
"adjustment"
If the dang thing broke ,to keep the piano going I would have installed 
one of the halves  somehow or went to the hardware store and stuck a 
coil spring between the inside of the case and the frame and ordered 
replacement(s) from one of the supply houses,
Come to think about it I've seen return springs with just one "wing "  
which would obviously  reduce the resistance at the pedal. Permanent fix 
? Maybe , maybe not but
as I tell a new technician I've been working with:    " Just find a way "
Respectfully ,
  Tom Driscoll





On 8/18/2012 10:28 AM, David Skolnik wrote:
>
> Before this thread vaporizes, what seems would be helpful would be a 
> clear explanation of what's involved in modifying this material: 
> tempered spring steel.  I don't think it would be that difficult to 
> fabricate a small press and, with perhaps the use of a torque gauge 
> (like the dial one we use to measure tuning pin torque) be able to 
> measure, fairly precisely, the strength of an individual spring, 
> reflecting how much pressure is required to deflect spring a given 
> amount.  Of course, the height (distance between planes of screw holes 
> and active contact surfaces of spring) would be an important factor.
>
> The other ambiguity remains how to successfully modify it.  We have:
>
>
> slow deformation, past what point?
> sudden impact
> (Wim standing vs. jumping - does Wim need to eat more, or less (to be 
> able to jump higher?))
> heat
> should there be hot coals under the spring Wim is jumping on? (to heat 
> the spring or make Wim jump higher?)
>
> Are there some changes that are temporary and others that are more 
> permanent?
>
> I'll ask a related question about lube on a spin-off thread.
>
> David Skolnik
> Hastings on Hudson, NY
>
>
>
>