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Dave Baker - Puma Race Engines (www.pumaracing.co.uk)
Doc wrote in message
ink.net...
Looking for any tips/tricks for drilling a hole w/a drill press that's as
close to dead-center to a specified point as possible.

Here's what I've been doing - I have the position marked with graph paper
that's taped to the workpiece. With the help of a magnifying glass, I
painstakingly move the piece until the tip of the bit is aligned with the
conjoining lines. By aligning with the tip I mean I view the tip both from
the narrow or "pointy" persepective within the channel of the bit and then
turn it 90 deg and look at the the wider perspective, and view it from the
side and front to make sure I have it aligned with both the X and Y axis.
When I finally get it so the tip is as centered as I can make it whichever
way the bit is turned and in relation to both axis, I clamp the piece to
the
plate of the drill press and drill the hole. However, on examination, the
hole comes out obviously not dead center in relation to the graph paper
lines.

I've also tried aliging it with the drill running, going visually by where
the "point" appears to be when the bit is spinning. I get somewhat better
results this way but wonder if there's a more precise and dependable way
of
achieving a centered hole.

Thanks for any input.

Turn a sharp point on a bit of thin bar in the lathe and use that in your
drill chuck to centre on your graph paper. Ideally make it with a collet
chuck or 4 jaw chuck to get it dead concentric. Then use a centre drill to
start the hole before drilling right through.

Your pointy bar will also come in handy for setting tool heights exactly on
centre on the lathe. I have a couple of them in various sizes made out of
old engine valve stems and bits of ground silver steel.