Further info on Stway "B" regulation

[Frank Weston]

Rolland Miller wrote:
> 
> Hello list.
> 
> A big "Thank you" to all who responded to my request for help.
> 
> I  "diagnosed" the piano today and it had a 1st in it for me - bare felt
> knuckles - no buckskin.  The knuckles were about 13/16" in diameter.  13/16" is
> the diameter of a steinway knuckle (with buckskin) I have in my shop.  I called
> Steinway about it and the technician that I talked to had not heard of a
> Steinway with bare felt knuckles.  He said he would mention it to Mike Mohr and
> Mike would get back to me after he got back from vacation.  My customer said
> that he believes all the parts are origional.  He has owned the piano since it
> was new.

I ran across a Steinway action circa 1969 with felt knuckles about six
months ago.  The felt knuckles went with teflon coated jacks and teflon
bushings.  This experiment by Steinway apparently did not last too
long.  Does the graphite on the wippens look green?  If so, it's
teflon.  I changed this whole action because of the unevenness of
operation, and just a little bit of clicking and clacking.

> 
> Back to the action.
> Action spread was 4 13/32" at hammers 1 and 88.
> I didn't get distance from knuckle to flange pin nor did I get either flange pin
> to hammer, or hammer bore.
> When setting glides I found that the key frame was not well bedded to the key
> bed as the middle of the K frame had good contact and the ends were about 1/32"
> above the key bed.  I did not try to remedy this problem as this was an attempt
> to diagnose? rather than repair.
> 
> Regulation specs after setting glides,
> Key height from bottom of key frame to top of white = 2 1/2"
> Key dip very close to .390
> Let off was close to 1/16".
> Hammer blow was about 1 5/8".
> Drop was just a bit low at about  1/4" - the drop screws were turned way down.
> Except for the hammer blow distance and drop measurement, these were about the
> specs I would aim for myself.


> Testing with the above specs,
> I found that the jacks still blocked hard.  Way too much after touch - I didn't
> bother measuring it.
> 
> Trial and Error,
> I found that a key dip of about 5/16" and a hammer blow of about 1 7/8" would
> get an after touch of about .060.
> On the other hand a key dip of .390 and a hammer blow distance of 2" plus would
> get an after touch of about .060.  This 2" plus hammer blow won't  work tho as
> the shanks are resting on the rest cushion and the hammer tails would normally
> catch on the backchecks.
> 
> If I have to, I think I can get a "working" regulation with a key dip of
> slightly less than 3/8" and a hammer travel distance in the 1 7/8" range. I
> don't like the specs though and would like to further evalute the action
> geometry to see if I can find a solution that will keep the key dip, hammer
> travel and after touch closer to their "design" range.

Things I would try:

Set let off to just short of kissing the strings, set hammer blow to at
least 1 7/8" or as much as possible.  

If you still can't get proper after touch, further increase hammer blow,
trim the felts on the wippens and regulate the backchecks if necessary.

The above failing, investigate to make sure the felt knuckles are a
proper match to the rest of the action components.  If not, I have a
complete set of Steinway teflon wippens that just happen to match the
felt knuckles (Guess what, I have the shanks and flanges too).  I'll
make you a great deal.

Good luck,

Frank Weston