Jon: If you woud like my address to send to instead of the group mail, let me know. I read this posting every day. Thanks > [Original Message] > From: Jon Page <jonpage@comcast.net> > To: <pianotech@ptg.org> > Date: 12/3/2004 4:44:24 PM > Subject: replacement knuckles > > One could mic the breadth of the knuckles and group them accordingly > but probably the main objective would be to press them into the slots > with a caul to aspire to more consistent results (jpg attch'd). > Then a further measurement of knuckle height could refine the shank groupings. > > On a new set of shanks, I sort first by shank SW sorting those to > sub-groups of knuckle height. > > The knuckle_caul.jpg which is attached is the first prototype, made from > mahogany. Consistent results were not achieved because the wood compressed > as the procedure progressed. My next one would be made from HMD plastic. > One machined of metal would be cost prohibitive for my purposes. > Here's a tool waiting to be produced... Joe, ... Bill, ... anyone... > > I have used the caul to compress the knuckle to conform to a tolerance > but have not followed up on measuring after a few years. > > I maintain a .010"/.25mm window of tolerance for knuckle height with the bulk > in-the-middle (say ~.640") and hi's (.645") & lo's (.635") off to their > respective sides. > (Shank height does not vary enough to be a consideration). > > By grouping the knuckle heights, a smoother regulation is attained; one > item evident of this > is a straighter let-off button alignment. > > Just one of the plethora of hair-splitting, nit-picking details which > consumes our work hours. > > I'm tired just thinking about it. > > > Regards, > > Jon Page, piano technician > Harwich Port, Cape Cod, Mass. > mailto:jonpage@comcast.net > ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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