[pianotech] pinblock drilling clamp

[Bruce Browning - The Piano Tuner]

Wim & Terry,
This is due to the drill bit running in the hole without moving through,
for an instant, thus not drawing the block up.


> I don't completely understand why it happens, but when the dowel, which
> does come down at the same rate as the drill bit, contacts the pin block,
> it "releases" the drill bit, and allows it to come back out of the block.
>
> The dowel is about 6" long. To make sure it does it's job, before I start
> drilling, I lower the drill to the side of the block, and look to see that
> the bit is about 1/8" past the bottom of the block. That's the point the
> dowel should touch the top of the block. When each hole is drilled, when
> the bit goes through the bottom of the block, that's the point at which to
> dowel hits the top of the block. The drill is brought back up, and the
> block stays where it is, without having to hold on to it, or clamp it
> down.