[CAUT] Bushing cloth thickness

[David Ilvedson]

Everyone agrees that the addition of teflon powder with new bushings is a good idea?



David Ilvedson, RPT

Pacifica, CA 94044









Original message

From: "Fred Sturm" 

To: caut 

Received: 8/1/2007 5:02:32 PM

Subject: Re: [CAUT] Bushing cloth thickness





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 “sizing,” which seems pretty temporary beyond a small amount. You need quite a bit of pressure, time, and heat to create a “permanent” 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, “allowing” 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 “iron” 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 don’t 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 “the keybushings, stupid!” 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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