Sticking Jacks

[Marcel Carey]

I would supect either the jack flange bushing or the whippen bushing. Take
out one whippen and test the friction for these. Also, is the backchecking
well regulated ? I've also seen cases where the jack can get caught between
the butt and the jack stop rail (sometimes let-off rail).

Good luck

Marcel Carey, RPT
-----Message d'origine-----
De : Philip Jamison <mortier@netreach.net>
À : pianotech@ptg.org <pianotech@ptg.org>
Date : 28 mars, 1998 08:46
Objet : Sticking Jacks


>   I'm working on an Acrosonic console from the '50s with a sticky
>treble. Most notes in the top third stick after much play (maybe once in
>30 hits). It's very erratic. I eased the keys and lubed the flanges
>which only partially helped. The whippen stays up, not the key, but the
>whippen drops when the hammer is pushed forward just a bit, so I think
>the jack is sticking against the butt. Sure enough, the butt felts
>(buckskin?) are graphited heavily. I replaced one with buckskin dusted
>with teflon. It stuck even worse than the others. I then put in a
>heavier jack spring, and this seems to work, but it gives a heavier
>touch. I've seen this problem in other pianos. Some tuners have glued
>weights to the whippen, etc. Any ideas?
>
>Thanks,
>
>Philip Jamison
>West Chester, PA
>