At 15:50 -0400 1/5/10, William Truitt wrote: >Some other caveats, which you probably already know: > >Keep your drill bits sharp, and start the first contact with the molding >with a very slow feed so as to avoid skating when the hammers are at an >angle other than 90 degrees. Also, use short hammer boring bits, such as >you can get from Pianotech, and keep the exposed bit as short as possible, >all to avoid flexing of the drill bit. Some while ago I posted photos and a description of the machine I made years ago: <http://pianomaker.co.uk/technical/boringmachine/> As to the drill bits, yes they must be short but they are special in other ways too. First they should have a slow spiral and then they should be centre-pointed with special spurs and a special end profile. I had mine ground up to order based on the drills that Abel used because they are not available in commerce. A clearer picture of this is shown below. -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://ptg.org/pipermail/pianotech.php/attachments/20100502/fd204551/attachment-0001.htm> -------------- next part -------------- A non-text attachment was scrubbed... Name: drill2.jpg Type: application/octet-stream Size: 80418 bytes Desc: not available URL: <http://ptg.org/pipermail/pianotech.php/attachments/20100502/fd204551/attachment-0001.obj>
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