John To drill for screw holes, first use a bit that is the same diameter of the shank of the screw. (the part of the screw without the threads). Measure the length of the shank, then place a piece of masking tape, with a "flag" on it?on?the bit at the length of the shank, plus the thickness of the plate. Drill the hole only as deep to where the flag of the masking tape touches the plate. After that hole is drilled, the next bit should be the same diameter as the inside diameter of the screw. Drill all the way through the block.? Wim -----Original Message----- From: John Ross <jrpiano at win.eastlink.ca> To: Pianotech List <pianotech at ptg.org> Sent: Tue, Sep 1, 2009 11:17 am Subject: [pianotech] pinblock Question How do you predrill the holes for the screws? It has been a while, and I can't remember what I did previously. I have the tapered bits from Lee Valley, but the screws are still too tight in the test piece of pinblock. The taper is all wrong for the 'fat' screws. I was thinking, of double drilling, part way with the thicker one, then go with a smaller size, same as the shaft thickness. Other question is, I am going to be using #1 pins, and want to use 'the Nossaman' system of double drilling, rather than using the air stream to cool the bit. What size for the first and second passes? John Ross Windsor, Nova Scotia. -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://ptg.org/pipermail/pianotech.php/attachments/20090901/5e2f12a0/attachment.htm>
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