Steinway "pinning" dilemma

[Roger Jolly]

>Hi Fred,

                  4gms of friction seems to be the optimum for tone 
production, as it keeps the knuckle firmly in contact with the 
balancier.   I usually demonstrate the effects of friction in my Prelude to 
Voicing classes.   There is usually a lot of slack jawed experienced techs, 
at the end of the demonstration.

Regards Roger.

>Hi Jim,
>    Thanks for your report on Eric's comments. Very interesting and useful.
>     I don't think the low friction has anything to do with heavier 
> hammers. To the
>best of my knowledge, the increase in hammer weight was addressed with
>design changes - particularly change in knuckle placement with resultant
>increase in dip, but I believe there were a few other, more subtle changes as
>well. I've had more of a tendency to suspect that the statement "as long 
>as the
>center is firm, it doesn't matter how much friction there is" had more to 
>do with
>setting limits on warrantee liability. To put it crassly, "If you want 
>more friction (for
>whatever reason), that's fine, but Steinway isn't going to pay." 2 grams has
>always been my absolute bottom limit, and 1 seems awfully low. But I'm 
>willing
>to suspend disbelief to a certain extent.
>    The friction in a hammer flange doesn't transfer directly 
> (numerically) to
>downweight at all, and certainly doesn't multiply. Hammerflange friction is
>usually a fairly small portion of overall friction, which is a small 
>portion of down
>weight. The largest portion of action friction is knuckle to rep 
>lever/jack, then
>wippen cushion to capstan and keybushing to keypin. Action center friction is
>generally the smallest portion. Unless action centers are nearly frozen, 
>their
>contribution to measured DW (or friction calculated from DW and UW) is well
>within 5 grams. As Don Mannino noted in an earlier post, he finds increasing
>hammershank center friction from zero to (I think it was) 4 grams 
>increases DW
>by only 1.5 grams, which sounds about right.
>Regards,
>Fred Sturm
>University of New Mexico
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