DoN. Nichols wrote:

The first rule with any reamer is *never* turn it backwards. It
chips the hardened cutting edge.

I think that the step drill would still be the best bet for
this, if you are going to pilot drill through. It will make smooth
round holes.

For the straight reamers, there are two styles -- the ones with
the square on the end for a tap wrench which are made for hand use.
They have along chamfer on the end to help getting it started cutting,
assuming that your pilot hole is close to size.

The other has a long round shank and is called a "chucking
reamer", intended to be used under power -- often in a turret in a
lathe for taking a hole to finish size just after the previous
station drilled it a little undersized. It has a very short chamfer
and is pretty useless under hand power. And often a bad idea in a
drill press too.

Rats, well I'll get to play with a reamer one of these days. I guess now I
have another excuse to have to get a lathe.

O.K. I hope that your drill press frame was well grounded
through the power cord -- or that the outlet was equipped with a
ground fault interrupter. Otherwise, you are in serious danger.

It was, but don't forsee utilizing that setup again. It did work at the
time, though.

Here is a picture of one of the completed units in it's assembly for
you to guess out the
purpose: http://img15.imageshack.us/img15/7540/jonpart.jpg

Hmmm ... mounted in a piece of plexiglass with a curved edge
which looks as though it may form a complete circle.

3/8" rod -- the hole you say is only 1/8". It might be the size
of the center insulation of a coax cable just a bit smaller than
RG-58. I think that I see the impressions of the braid in the OD. It
is not precisely enough made to be a proper gas-tight seal. It looks
as though you have flats filed near the end for a wrench which
suggests that you are trying to adjust the extension. Perhaps some
kind of spark gap, sparking against something not visible in this
view.

If there were metal extending beyond the insulation I would
consider it an electrical feedthrough, especially since I seem to see
a ghostly image of the same projection on the other side.

Hmm ... perhaps the Plexiglas is a full circle, and the whole
device is intended to carry a spark between electrodes spaced on
either side of the Plexiglas as it rotates?

Yep, it's a spark gap, you get the cigar. This one is used for a tesla coil
(they don't like you building them for transmitters anymore).

http://img580.imageshack.us/img580/8080/gap04.jpg

BTW -- this (drilling though the center) is the kind of task which a
lathe with the bit in a tailstock chuck would have been better at.
Yes, keep backing the bit out (peck drilling) to clear the chips.

Indeed, and thanks!

Jon