Hmmm... My method was a bit more ad-hoc then what you suggest below... but next time around I certainly will strive for more accuracy. That said, what I did was carefully sand away the needed bit with a thin vertical belt sander... eyeballed all the way. Admitedly a bit less then perfect accuracy. Still the main problem seemed to be that it was difficult to get the depth right... ie maintaining the proper centerpin height. I had to shim a bit more then usual for such jobs... but all center pins are dead on line... perhaps better then otherwise really... I looked at a 12 year old C today.... not allllllll that straight a line. But to the ratio question you raise.... since the actual distance from the centerpin to the knuckle and hammer doesnt change... the hammer ratio itself stays the same. We are talking then only about whatever affect a say 1 mm variance in centerpin placement would have. That gets into the distance to the whippen center... which is very rougly at a 40 degree angle from any horizontal variance in the hammer shank center... so we are talking very slight variations... Still... I havent thought about this particular issue before... only in terms of more generally discussed spread issues. I'll have to take some extra notice to what happens when I move things around a bit. Thanks for the post Ron RicB Overs Pianos wrote: > At 10:59 PM +0100 19/9/04, Richard Brekne wrote: > >> >> As it turned out, I got to thinking and looking and pondering and >> ended up just filing the front (hammer end) of flange profile back >> enough so that I could get the centerpins lined up with the old >> center pin line. This was a bit time consuming, but it got done in >> about 3 hours. It required a bit extra in terms of shank traveling >> and making sure the centerpin heights were even... but not so much >> extra in the end. > > > The idea is fine, but reducing flange length accurately by hand is a > most difficult thing to achieve. Any variation in length will > translate directly to variations in the hammer/key ratio. > > If you can manage it, a slitting saw and makeshift jig is a better > method for accurately changing action part dimensions. > > Ron O.
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