[CAUT] Down Weight Too High With New Hammers

[Fred Sturm]

On Aug 23, 2010, at 2:53 PM, Paul Milesi, RPT wrote:

>  Just wondering if
> this touchweight issue is common when putting new hammers on a  
> Steinway D
> from this period, and if there is a typical or common remedy or  
> approach to
> solving the problem.


	From what you have said, it appears to be a weight and geometry  
issue. Those high upweights indicate reasonably low friction. Key  
leading on the heavy side sounds typical and removes the option of  
adding lead (though I wouldn't rule it out entirely - not having seen  
what you have seen, anyway). Roger Jolly is probably right in saying  
that cleaning and lubing the rep springs and grubs will make it feel a  
little lighter, but I don't believe it will change downweight/upweight  
(they aren't engaged during the part of key travel that is measured  
for weight). The change in feel will occur at the end of the  
keystroke, and can be very noticeable if there was caked grease and  
crud in there.
	I don't understand how the old geometry wipp can cause a difference  
in weight/ratio compared to the new one, but experience seems to say  
it can. After all, the capstans are touching the wipp heels at the  
same point, and the jack/rep lever is contacting the knuckle at the  
same point, whether it is new style or old. I guess it must have to do  
with the angle at which the jack addresses the knuckle, as that  
certainly does change (enough to require different thickness let off  
buttons). It wouldn't seem that changing one factor - the knuckle  
distance - would make that much difference, but it seems that it does.  
The newer wipp has very subtle differences in things like jack  
profile. This thread makes me curious to look very closely at just  
what those differences actually are.
	In any case, as a practical matter, the easiest thing to address  
might be weight. Reduce each hammer 1 gram, and you are in a better  
ballpark. Not a walk in the park, but doable (or close - 1 gram is  
about the max you can comfortably remove from a hammer by re-arcing  
and tapering). It does require removing and replacing all the hammers  
and shanks (and re-aligning), and a bench disc sander at a minimum,  
with Spurlock's tail arcing device or equivalent. Tapering can be done  
fairly evenly by timing and feel (how long and hard you hold the  
hammer against the sanding disc, balancing from one side of the hammer  
to the other). A scale to weigh before and after. You will need to  
taper into the felt area (not all the way to the crown) to get enough  
weight reduction.
	If it weren't a Steinway, I'd look at a quick geometry change using  
split balance punchings. But it is a Steinway, so no soap. At least  
not that I know of. Maybe Ed Sutton's idea about shimming the wipp  
would work. Worth the experiment.
Regards,
Fred Sturm
University of New Mexico
fssturm at unm.edu