[CAUT] Anodized aluminum pins and capstans

[Fred Sturm]

On Dec 3, 2009, at 7:24 AM, David Stanwood wrote:

> Pushing sideways against the front rail pin and moving the key up  
> and down to feel the increase in friction is an important test that  
> we all need to do on every piano we service. It's an issue for the  
> quality of piano playing because pianists often strike the keys at a  
> glancing angle ant the frictional touch weight increases  
> dramatically if the coefficient is high


	Another aspect is the glissando. And one of the best ways to check is  
to do a pianissimo glissando: fingertips (fleshy part, not nails) at a  
very acute angle to the keyboard, up and down. It is usually very,  
very revealing. If there is undue friction, it becomes next to  
impossible to keep the fingers moving without applying much more  
force, hence making the gliss much louder. If it is well lubed, a very  
light pressure can produce a light shimmer of sound.
	One experience I remember very well is a pianist, Evelyne Brancart  
(she taught here at the time, is now piano head at Indiana), telling  
me she needed to do sixth glissandi with one hand on a particular  
piece, ie holding the fingers in a position to cover the interval of a  
sixth and sliding chromatically. I tried that, and it really woke me  
up to the issue.
	While I concur with concern over environmental issue of materials, if  
the pins are plated and the bushings are felt (or leather), there  
needs to be lubrication. For me, that means McLube for the pins and  
teflon powder or occasionally Protech CLP for the felt. The anodized  
pins may reduce the need for lubrication, but I think I would still  
lube the felt. Use as little as possible in a focused way. Apply  
liquids with a cloth or brush, not a spray, for example.
	BTW, use of anodized capstans should not only prolong the life of the  
wipp cushion felt, it should also make the regulation last better: the  
felt will wear less and pack less, so raising the capstans won't be  
needed as much over time.
Regards,
Fred Sturm
University of New Mexico
fssturm at unm.edu