Jon - Thanks for pictures and tool suggestion. If you can, please fill in some information: At 11:01 AM 11/26/2010, you wrote: >Roger & Ed, thanks for the encouragement. Here's a photo of the relocated >knuckle and reinforced yoke. > >This is a 1971 L donated to the Cape Cod Conservatory. Heavy action, high >friction readings but no binding components. A 40 year old piano. Was it previously resident on the cape? Hammers must have had minimal wear to make it worth the procedure, even if knuckles were gratis. 40 years old, with relatively little playing. Did you confirm that there were no other relevant contributors to friction? >Moving the knuckle should drop the friction to a reasonable level. . Did you confirm the improvement before doing them all? >The original knuckles were 11mm wide. This produced excessive after >touch and a drop screw head buried into the flange. >I'm confident the knuckle relocation and size reduction will bring the action >around to a manageable regulation. I understand how the excess knuckle height (vertical diameter) would produce the buried drop screws, but not so clear about how the size (as opposed to the leverage advantage created by 16mm distance to pin) caused excessive after touch. If the knuckles had been in good condition, could you have achieved your goal by re-using them? What size did you go down to? I hold out some suspicion (not confirmed by me) that the smaller radius knuckle offers somewhat more resistance to jack escapement. >One argument to be made for not replacing the shanks is that these >are seasoned, >new ones would travel and twist in the coming years. I think Teflon >bushing are >Ok, it's the unstable wood around them that causes the problems. Hate to keep coming back to piano's age, but why would wood continue to be unstable after 40 years? Did piano have either of the classic teflon issues (clicking or too tight) before coming to the conservatory? What's the typical humidity swing in its new home? Last details: Did you do as Ed Foote had described in punching out all the bushings, treating, and then reinstalling? If so, did you have to re-dimension the holes prior to repinning? Would you have used the old bushings? (unlikely). Sorry for minutia, but you seem like the sort that would have considered all this. No argument about fun and games. What else have you used the chop saw for? David Skolnik Hastings on Hudson, NY -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://ptg.org/pipermail/caut.php/attachments/20101126/c9f194a9/attachment.htm>
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