[pianotech] key bushing problem

[Paul Milesi]

David Ilvedson has very nicely articulated the important details: use the
final caul (not the keypin) as your guide for choosing cloth; have on hand
as many cloth thicknesses from as many sources as possible; choose a cloth
thickness, using the final caul, that is quite snug; insert the sizing cauls
immediately after removing old bushings; let both the sizing cauls and the
final cauls remain in the mortises overnight.  That should get you a very
good result.

Paul Milesi, RPT
Washington, DC
(202) 667-3136
E-mail:  paul at pmpiano.com
Website:  http://www.pmpiano.com


> From: David Nereson <da88ve at gmail.com>
> Reply-To: <pianotech at ptg.org>
> Date: Tue, 26 Jan 2010 19:08:39 -0700
> To: <pianotech at ptg.org>
> Subject: [pianotech] key bushing problem
> 
>     I rebushed a set of keys using the nylon Spurlock cauls.
> The pins were .146" so I used that size caul.  When done, the
> keys still wobbled laterally (balance rail).  This has happened
> a couple times now.  I had done no easing or ironing after
> removing the cauls.  Should I have used a smaller caul (even
> tho' the size I used is meant for that size pin) or thicker
> bushing cloth?  Or both?  When I initially determined what
> thickness cloth to use, by laying the trial cloth across the
> mortise and pushing a key pin into the hole, thick seemed way
> too tight.  Medium was just right (could be pushed in, but
> holding the key upside down, the pin would not fall out -- this
> is according to the Spurlock directions).
>     Once I steamed 'em all back out and rebushed with thicker
> cloth, but using the same cauls, and they still came out too
> loose (too much lateral play).  So do you use a smaller caul
> than the one intended for a given size pin?
>     --David Nereson, RPT
> 
>