[CAUT] Bushing cloth thickness

[Fred Sturm]

On 8/1/07 4:02 PM, "Mark Cramer" <Cramer at brandonu.ca> wrote:

> However, when the bushing rides the pin down, much like normal playing
> conditions, even on a polished/Pro-lubed pin, there is a definite sensation of
> the fuzzy un-finished felt, and I don't like it!

I agree. This is more the reason for ironing than ³sizing,² which seems
pretty temporary beyond a small amount. You need quite a bit of pressure,
time, and heat to create a ³permanent² dimension change. But ironing, though
it may not make the side play feel perceptibly different at all, reduces the
drag, probably mostly by tacking down the fuzz and knitting it to the rest
of the felt. 
    I notice it when trying the bushings by using a loose key pin (keys
still in the clamp): a very loose hold on the pin, ³allowing² it to
move/float from front to back of each bushing mortise. Ironing makes a very
noticeable difference. Similarly, when testing keys on the keyframe using a
weight (I use half and full jiffy leads) to counterbalance the lead in the
keys. The difference between ironed and un-ironed is really rather dramatic.
    Okay, not that much time in the practice room would probably ³iron² the
bushings through friction, at least in the middle of the keyboard, for
purposes of avoiding sticking keys, though it will be in the middle of the
bushings, meaning a cupped profile. But if I am wanting to do anything with
measuring touchweight, even just rapid diagnosis of extra friction (upweight
using 16 gm, then 20, then 24 on each key, just chalking the ones that don¹t
rise, that kind of thing), getting the keys as near frictionless as possible
beforehand makes life much easier. 75% or more of the time I would find it
was ³the keybushings, stupid!² before I started ironing as a standard
procedure. And then it means pulling the stack or using the offset bushing
pliers, which I prefer to avoid.
Regards,
Fred Sturm
University of New Mexico


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