[pianotech] pinblock drilling clamp

[tnrwim at aol.com]

Mike
 
I had the same problem you describe, the pin block riding up on the bit. I used to hold the block down with my forearm, but that seriously bruised it. What I wound up doing is attaching a dowel to the guide, which on your press is to the left of the chuck. I drilled a 5/8" hole in one end of a 3/4" dowel, and attached a 5/8" diameter T-Nut. On the guide, I put a 5'8" bolt, and screwed the dowel to the bolt. The dowel is long enough so that when the drill is all the way through the block, the bottom of the dowel would hit the pin block. That would release the bit, and you're ready to drill the next hole.  No clamp to tighten and release, and no bruised forearm.  

Wim





-----Original Message-----
From: Mike Spalding <mike.spalding1 at verizon.net>
To: Pianotech <pianotech at ptg.org>
Sent: Wed, Aug 11, 2010 2:03 pm
Subject: [pianotech] pinblock drilling clamp


I learned to drill pinblocks out of the piano, and even though Ron N's 
rguments for doing it in the piano are quite compelling, have never 
otten around to setting up for that process.  Step one, find a radial 
rill press.  Nope, not yet.  But I need to improve the consistency of 
in torque, and thought that double-drilling  might be the answer.  I 
now from painful past experience that you need a pretty effective 
old-down for the second drill, else the workpiece will climb up the bit 
ntil it hits the chuck, then commence to spin.  At that point, all pin 
orque consistency is gone.  So in preparation for my next pinblock, 
've prototyped a hold-down clamp.  Thought you might be interested in 
eeing this..  The photo shows test holes being drilled in a piece of 
inblock scrap.  pilot drill 7/32, final drill "F" .257.  Pins in the 
est piece are reasonably consistent - 125 to 150 in-lb.  Of course, the 
eal test is 224 pins in a real piano, so I'll let you know later how it 
orks in production.  Meanwhile, I'm curious if anyone else has taken 
his path, and if so, with what result?





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