[pianotech] Square grand Key pins and Backchecks

[Joseph Garrett]

Terry said:
"Front rail keypins are 0.146" - so no sweat there. However, the balance
rail keypins are 0.154" - what's up with that? Any recommendations? 
 
I was thinking of trying my new bottle of Pianotek Profelt - but they don't
have cauls for a 0.154" hole. I suppose I should just replace the bushings
anyway........ Any thoughts?
 
Other item is backchecks. Looks like the originals had two layers of
leather on the back and then on the front, one layer of leather and then a
thick layer of dense felt - something like hammer felt. Anyone know what
type of felt this is - and a source?
 
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Thanks!
 
Terry,
Gawd, by the time we're done with all of these questions, I'll have written
that book on the damned subject! (I've been putting that off for a very
long time!<G>)
The key pins are typical of Steinway. There are culls for the .16?" pins on
their Grawnd pianers. Use those and just pull them right after the glue has
cooled but not set. Will work just fine, imo.
As for the Backchecks, here's how those are made: a piece of leather,
similar to thin shoe leather on the back & front, glued around a flattened
wire w/serrations. Then, (and this is variable from piano to tpiano), a
medium thick piece of what I used to get from Pacific Piano Supply as
"Understringing Felt". It is softer than the Upright backcheck felt and
less than the normal 1/4" thick. After that, there was usually something
like thick Elk hide, suede side out for the tail to check on. Sometimes the
whole thing was all leather and the softer stuff was usually Rabbit. I
would advise close scrutiny to see what it really is. IF it is not
excessively worn, (beyond surfacing with a sandpaper file/120 grit paper),
then LEAVE IT ALONE! Sigh!<G>
Regards,
Joe


Joe Garrett, R.P.T.
Captain of the Tool Police
Squares R I