Key Bushing Clearance/Friction, was: Key mortise correction

[David Ilvedson]

David Stanwood had a good suggestion of letting the key come down with your fingers but if you feel the key get lighter as the keypin/balance rail bushing happens the bushing is too tight...

David Ilvedson, RPT
Pacifica, CA 94044





Original message
From: "Roger Jolly" 
To: "Pianotech List" 
Received: 8/13/2006 9:38:01 AM
Subject: Re: Key Bushing Clearance/Friction, was: Key mortise correction


Hi Terry,
                    The brass cauls will take all the guess work out of key fitting.  The Rheostat is some thing I have been meaning to purchase for about 10yrs ;-), I used to use the Teflon powder, but have found the very thin smear of protech grease faster, and giving similar results.  Dave had a concern about dirt sticking to the grease, quite valid.
I have not noticed a problem and have been doing it for yrs.
A point to stress. Sizing the bushings is always the first step, so you can accurately trouble shoot other potential problems..
 Letting the key slide down the BR pin will not tell you weather it is a bushing, BR hole, or mortice, that is causing the problem.  Ironing the bushing removes one element from the equation, setting the BR hole height, removes another element.   After this is done, now is the time to ease BR holes and NOT before.
Stabbing in the dark is not the way to attain high performance work. Thing the problem through is.

Regards Roger



At 05:44 AM 8/13/2006, you wrote:

Thanks Roger. I thought you might have some sort of fancy method of measuring the clearance of an existing keypin. I'm doing just about the same thing that you do - I use the brass cauls from Pianotek when I ease a set of keys. They also sell a little power regulator - forget what they call it - a reostat maybe - to control the temperature of the iron. You can dial in the perfect temperature - not too hot and not too cool. For lubrication I take a pipe cleaner, fold it over a couple times to increase it's thickness, dip it into the vat of powdered teflon and insert the pipe cleaner into the mortise and rub the teflon into the bushing. I've done this on a few very-high-use (cruise ship piano bar - talk about abuse!) Yamaha C3s with excellent long-lasting results.
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