FW: [CAUT] re-sizing pulley keys

[Alan McCoy]

Wim,

Check this out from Mark Cramer from last March. Hope it helps.

Alan


-- Alan McCoy, RPT
Eastern Washington University
amccoy@mail.ewu.edu
509-359-4627

------ Forwarded Message
From: Mark Cramer <Cramer@BrandonU.ca>
Reply-To: "College and University Technicians <caut@ptg.org>" <caut@ptg.org>
Date: Mon, 28 Mar 2005 09:53:17 -0600
To: CAUT <caut@ptg.org>
Subject: [CAUT] re-sizing pulley keys

For a time we we're re-installing freshly-steamed key-pin holes over the
key-pins to "size" the holes (propping the keys up with sticks acrss the
front and back rails).

(we were, (and still are), in love with Bill's (then new) mortise-sizing
cauls, at the time)

Though the idea (re-forming the wood around the pin) originally made sense,
it actually didn't work.

It seems the wood "withdrew" as wood moisture content returned to normal, so
the holes were beautifully and precisely round, but the fit was loose.
Make's sense?

Anyhow, what we've been doing since is to steam as before, then test fit the
keys after a day. Our typical shop RH is about 22% in winter.

We try to just polish/burnish the hole to begin with, then if that isn't
sufficient, we use the CF tool to re-size, per directions.

If the holes are over-size after steaming, we use the good old-fashioned
3-1 water/glue sizing on a wood screw (#12?) twirling it backwards to leave
a collar in the hole.

BTW, I prefer to add water/glue sizing to "steamed" wood fibre, rather than
"dry" wood. The working thought here is coating/surrounding/stabilizing the
loose, fuzzy wood-fiber rather than lining the hole with glue.

Also, surface tension seems to cause the sizing solution to "bead" rather
than penetrate the wood, unless the fiber has been opened.

In any case, I haven't noticed noise as a result of diluted glue-sizing,
(we're not very brave with the glue), though  acknowledge there is a limit
to how loose a pin-hole this method can repair.

Aside from Onesti's balance hole kit, I recommend anyone needing to actually
replace wood might also look in the PTG reprint series for Bill Spurlock's
take on the subject.

happy sizing!
Mark Cramer,
Brandon University

_______________________________________________
caut list info: https://www.moypiano.com/resources/#archives

------ End of Forwarded Message