How do I drill a stack of metal sheets accurately with a 1/8" or 3mm
drill? Assuming metal is 16 or 18 gauge steel, is there a special way
to sharpen the drill so it doesn't wander? How many sheets can be
drilled at once?

On Aug 22, 1:14*pm, N Morrison wrote:
How do I drill a stack of metal sheets accurately with a 1/8" or 3mm
drill? Assuming metal is 16 or 18 gauge steel, is there a special way
to sharpen the drill so it doesn't wander? How many sheets can be
drilled at once?

If you want accuracy, clamp 'em all on a mill bed, spot drill with a
center drill, then follow through with first a 2mm drill, then the
final
size, using appropriate coolant. If you can tolerate a
half millimeter of wander, you can do a 20mm stack in one go.

If you want convenience, dimple with a center punch and using
that (by feel) locate the center spur of a (for instance) Whitney
hand punch. Diameter with a punch is very repeatable, and the
hole sides will be smooth and parallel.

Good advice, but I'll differ on one point. Use a spot drill to establish the
hole start, then drill right to size in one shot. Me thinks this is more
accurate. At least, that's the way I do it.

Karl

N Morrison wrote:
How do I drill a stack of metal sheets accurately with a 1/8" or 3mm
drill? Assuming metal is 16 or 18 gauge steel, is there a special way
to sharpen the drill so it doesn't wander? How many sheets can be
drilled at once?



A drill bushing in a plate placed on top of the sheetmetal will give you
the most accurate hole location. Also use a drill with short length
flutes commonly used in aircraft sheetmetal work. You will be able to
drill a number of sheets at once if you have a factory sharpened drill.
You don't say how accurate you need the hole so you will just have to
experiment on the number of sheets that will give you the accuracy you
require.

John

On Aug 22, 4:14*pm, N Morrison wrote:
How do I drill a stack of metal sheets accurately with a 1/8" or 3mm
drill? Assuming metal is 16 or 18 gauge steel, is there a special way
to sharpen the drill so it doesn't wander? How many sheets can be
drilled at once?

Parabolic drill bits may give you better results.

jsw