[pianotech] hammer butt split at felt pad

[Joseph Garrett]

David B. asked: 
"A couple of weeks ago I wrote about the Problem Solving Customer who 
turned on his lathe a little aluminum collar for a hammer butt plate 
screw. He called me back this week to say that another note was causing 
problems, not repeating properly.
 
When I looked at the offending note today, I flicked the jack and could 
hear a charcteristic "click" that suggested the butt notch felt cushion 
was missing, or worn through to the wood, so that the jack tip was 
clicking against wood. When I peered with my flashlight, I could see 
that indeed it was missing. But not because the felt pad had fallen off. 
It had fellen off, yes, but because the wood had split. See photo. I 
found the felt pad in the bottom of the piano, attached to the bit of 
wood it was still adhering to. I've not seen a split like that before, 
but I was in keeping with the fact that all the action parts in this 
piano seem very brittle.
 
What would you stick this with? I chose to use CA glue, and I found 
that the wood absolutely "drank" it in. I am hoping that having applied 
enough, it will have filled up and strengthened dried-out wood cells, 
and that the thing won't break again. I could of course have replaced 
the hammer butt, but gluing was quick and easy.
 
Do you think another adhesive choice would have been preferable?
 
It seemed odd to me that it should break in that way, as no great 
forces are involved at the hammer butt notch, at least not under the 
felt pad.
 
Best regards,"
 
David,
I think the proper glue would have been Titebond III, rather than CA. CA
would wick into the surrounding area of the underfelt, etc., which, could,
cause further problems. Whereas the Titebond III would do what it was
designed to do, glue wood to wood and stay where it was put. Also, I've
found that Titebond III has a nice tack and work time that allows
alignment, etc. The trick with that job would be with the clamp. I have
several "spring clamps", modified to just put pressure in a vary narrow
area, so that trauma is not amplified.<G>
Hope that answers your question. BTW, Do you have Titebond products in the
UK?<G>
Regards,
Joe


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