Assuming a rather poorly set up key to wippen relationship and assuming a very short key (i.e., one typical of a 150 cm grand) the sliding motion will be about 0.2 mm (or about 0.008"). Most actions-properly set up and with longer keys-will have less than this. There is so little sliding motion between the capstans and the wippen that the capstans typically corrode and discolor. If there was any appreciable sliding motion they would polish themselves. ddf Delwin D Fandrich Piano Design & Fabrication 6939 Foothill Court SW, Olympia, Washington 98512 USA Phone 360.515.0119 - Cell 360.388.6525 del at fandrichpiano.com <mailto:del at fandrichpiano.com> - ddfandrich at gmail.com From: pianotech-bounces at ptg.org [mailto:pianotech-bounces at ptg.org] On Behalf Of Dale Erwin Sent: Saturday, September 22, 2012 7:05 PM To: joegarrett at earthlink.net; pianotech at ptg.org Subject: Re: [pianotech] re; Action Ratio Measuring Hi Joe Wether the casptan is straight or angled, watching it move thru its motion changes its contact point with the wippen heel. Not by sliding but by rotating. Its not much and I'll choose not to split hairs about it. Ok? Dale Erwin R.P.T. Erwin's Piano Restoration Inc. Mason & Hamlin/Steinway/U.S. pianos www.Erwinspiano.com Phone: 209-577-8397 -----Original Message----- From: Joseph Garrett <joegarrett at earthlink.net> To: pianotech <pianotech at ptg.org> Sent: Sat, Sep 22, 2012 6:51 pm Subject: [pianotech] re; Action Ratio Measuring Dale said: "All actions are subject the accelerating action phenomena to changing ratios thru the complete range of motion as the capstans is moving further from the wip center pin and the increasing leverage efficiency in the wip." Dale, I can't agree. The capstan does not move but a miniscule "...further from the wip center pin...". Del brought this to my attention during a Key class I was giving. I agree with Del, ...that there is little movement of the capstan along the wippen foot felt! They are so close to linear to each other that the differences of their arcs is pretty much negligible imo.<G> Joe Joe Garrett, R.P.T. Captain of the Tool Police Squares R I -------------- next part -------------- An HTML attachment was scrubbed... URL: <https://www.moypiano.com/ptg/pianotech.php/attachments/20120922/8721ae12/attachment.htm>
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