[CAUT] CAF

[Fred Sturm]

	I more or less started the part of this thread dealing with distance  
from cushion to shank. I'd just like to do one final summing up of my  
take on the issue:

	Manufacturers have universally, to the best of my knowledge, stated  
that shanks should not rest on cushions, but should be about a shank's  
width above, not much more. I'll take that as recommending a parameter  
of maybe 2 to 8 mm distance.
	In regulating grand actions, trying to come up with the best blow  
distance and dip, we often end up with shanks farther off the  
cushions, sometimes to an extreme. There are many underlying causes,  
but this is a reality most of us have faced.
	Many techs have decided that this distance above the cushions isn't  
important, as bench testing and action model experiments show an  
action will function adequately with larger distances.
	Field testing, OTOH, with actual pianists playing music on  
instruments, has shown that excess distance can lead to problems.  
Causes may vary. A common one would be tenor hammer felt contacting a  
check at some point during rebound and catching to a greater or lesser  
degree. There are many other possible scenarios, but in any case,  
experience shows that problems show up.
	Hence, IMO, when the distance is outside parameters, it is best to  
address it, most easily by filling in the space. I agree with my  
esteemed colleague Herr Solliday that (relatively) firm is better than  
soft.
	There are a lot of other reasons for action failure, and those should  
be addressed as well. Narrowing the gap between shank and cushion is  
not a cure all.

Regards,
Fred Sturm
University of New Mexico
fssturm at unm.edu