Ed: It is my understanding that on uprights, the hammers should under-center. I was taught that the amount should about 5 mm (= .200", just less than one hammer shank thickness). This helps the hammer rebound off the string better. The piano will not play properly if the distance: string to center pin is the same as the hammer bore. I know this is how European upright actions (Renner, Langer, etc.) are designed. I seriously doubt that the 1/16" more under-centering will be a problem, neither at the hammer rest rail nor at the strike line. If you feel compelled to compensate, you could do that by adjusting the action bolts. Jurgen Goering Piano Forte Supply (250) 754-2440 info at pianofortesupply.com http://www.pianofortesupply.com On Nov 18, 2006, at 11:00, pianotech-request at ptg.org wrote: > > I am installing new butts, shanks, and hammers into an old Knabe > upright. The replacement butts I bought are Tokiwa. I didn't think > much about the fact that these butts are made in Japan, and Knabe is > an American upright. ...snip > > I lined a new Tokiwa butt and shank up in the action, side by side, > next to the old butt/shank/hammer. It turns out that the placement of > the shank-hole in the new Tokiwa butt is a little over 1/16th of an > inch closer to the strings than the old butt. This puts the hammer and > shank at a different pitch resting on the hammer rail, and more > importantly at impact with the strings. > > With these new butts, the hammer will make impact with the strings > just BEFORE is reaches a 90 degree angle (assuming the original > geometry of the butt/shank/hammer to string dimensions did so). Will > this be a problem????? > > Your input is greatly appreciated. > Ed -------------- next part -------------- A non-text attachment was scrubbed... Name: not available Type: text/enriched Size: 1764 bytes Desc: not available Url : https://www.moypiano.com/ptg/pianotech.php/attachments/20061118/7c11ce4d/attachment.bin
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