Pinning and Tone

[fssturm@unm.edu]

   Thanks for your thoughts on this, Don.
   Going back to the original question, which had to do with current Steinway 
production and specs, I'd like to offer a little info I got from the factory this week 
(just got back from a week long seminar). First, how they produce the parts in 
the factory. The process is as follows:
1) Insert bushing cloth in hole - the cloth has glue on one side, but otherwise is 
unadulterated bushing felt. (Glue is activated by heat, or maybe microwaves or 
something. The glue is dry when inserted, somewhat like Renner bushing 
cloth).
2) Insert sizing pin, and set up a fairly large number of parts in a fixture.
3) Dip the fixture into a teflon solution (just the protruding bushings - the fixture 
is designed to have just a small portion exposed).
4) Allow to dry.
5) Remove sizing pin and pin parts together.
   That's it. I was careful to ask enough questions to determine that there were no 
further steps (eg, no burnishing). The teflon solution is not emralon/permalon. It 
has a solvent that is too volatile for shipping (hence not offered to techs). I 
examined the fixtures, and found dried teflon residue that felt and acted like thin 
sheet teflon (broke off a bit and fooled around with it. FWIW, it is white when 
dry).
   Current doctrine is that Steinway wants 1 to 3 grams friction, and that the teflon 
most definitely makes a firmer action center than untreated felt. This from a 
couple people in technical support and C & A. They say they definitely want the 
lower friction - that it produces better responding action. This is by design.
   I must say I was impressed by the action portion of the factory. It has been 
completely re-tooled and reorganized over the past 15 years. We had lunch with 
the guy who oversaw that for a period of ten years (and is now in over-all quality 
control). Very impressive person (I'm bad at names, and promptly forgot it). He 
was quite open about how bad things were when he started. Worn out 
machines - out of tolerance, slip shod production methods. That was when they 
were using Renner parts in B's and D's in production. Now all are made in NYC, 
and production of parts is enough that they are closer to keeping up with orders 
from the field.

Regards,
Fred Sturm
University of New Mexico

Quoting Don Mannino <dmannino@kawaius.com>:

snip
> - Too little friction causes no problems in tone at all in and of
> itself.  It is only because we are using cloth bushings that low
> friction results in poor tone because the hammer is not controlled
> in
> its motion well enough.  Please understand me here - if you have a
> very,
> very firm bushing that will pin with low friction and still have
> excellent side control, the tone should be fine.  It is the
> limitation
> of using a soft bushing material that forces us to pin with
> sufficient
> friction to get the control we need.  It is not the friction itself
> which gives good tone - it is the firmness of the bushing.
snip
> Don Mannino