Key pins and key bushings

[David ilvedson]

Actually we use three different thicknesses of bushing cloth to 
make up for differences.  In the case of .144 pins and .146 
cauls use a thicker cloth.  I test with different sizes and I want 
a snug fit before the glue.  Bill Spurlock say you can hold the 
caul and shake it and the key will reluctantly come away.  The 
biggest problem is mortise size differences.  Bill uses two four 
inch bastard files epoxied together to size the mortises so 
they are more even.  After all this yes I do turn the front pin on 
the odd few that could use it.  Does the list think the Renner 
cloth is the best quality?  I haven't tried Pianotek's cloth.  

David Ilvedson, RPT

> Yes, I agree Newton.  Occasionally we rebush keys for which the pins
> measure 0.144.  Our cauls are sized for 0.146 pins and tend to leave the
> other with slightly more play than we prefer.  In this case, I have no
> concerns with turning the front pins slightly.
> 
> It is less acceptable (though certainly not damaging in any way) to turn
> the pins in order to take up side play resulting from worn bushings.  The
> 'nested' bushing cloth will contact a greater area of the pin resulting in
> greater friction.  Also the bushing may be worn through to the glue layer
> which obviously increases the friction as well.
> 
> Regards,
> 
> Stan Kroeker
> Registered Piano Technician
> 
> www.pianoexperts.mb.ca
> 
> 
> 


David Ilvedson, RPT
Pacifica, CA
ilvey@jps.net