DoN. Nichols wrote:

Hmm ... what kind of reamer? Single size reamers are really
designed to remove very little metal from a slightly undersized hole
to produce a precise hole size. I don't think that one would work
well in a tri-lobed hole.

Or -- if you are talking about a tapered reamer, that (under
manual power) might do reasonably well. The one I'm most familiar
with goes from perhaps 3/16" to 1/2" with a T-handle. There are
larger ones designed to ream the ID of pipes to remove burrs. These
are fitted with the square shank which fits a brace (drill holder for
wood bits). That, with a brace might work well, as long as you had a
way to make sure that you stop before the hole gets too large.

Well, I hadn't exactly completely throught through that part of the process.
I also have no experience in actually using a reamer, so you could say I am
eager to get my hands on one to learn from it.

But if you insist on running one -- check whether the shank has
three partial flats on it. Without those, the bit is likely to bind
and the shank slip in the chuck.

Oh man tell me about it! This Delta of mine spins a 3/8" shiny
finish when it catches at the end of a hole, and drives me NUTS!

:-)

Do you use the chuck key in all three positions? This makes for
a somewhat better grip.

Until today, I had never come across that pearl. Whatever I take away from
my recent expeditions, this will remain the most valuable.

If you have a milling machine and a spin indexer, you could
machine your own flats on the shank if it turns out to not have them.

A few years ago I tried to "roll my own" flats on a spade bit without using
the above mentioned tools. You can probably guess as to how that experiment
worked out.

Thanks for the suggestion, Don. I must admit that I really like
water because it is cheap and is easy to flow at a volume sufficient
to cool the bit and workpiece.

You use it outdoors? Indoors makes a real mess since you don't
have a way to capture and recycle the coolant. If you did, I would
suggest you use it with a soluble oil in the water -- made for steel
cutting.

I used it indoors at the sink for drilling 1/8" holes through the center of
1.5" long sections of 3/8" threaded rod. I had to go pretty slow once I got
in, and also had to pull the bit out frequently to clear the debris, but it
did work (ignoring the half-dozen mulligans). Mess was contained by setting
the drill press into a plastic-sheet lined basin near the sink, so the water
flowed into the drain.

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

The sulfur in the high sulfur cutting oil both lubricates the
chips (a high pressure lubricant) and reduces the strength of the
metal in shear where you are cutting.

Thanks Don, I will be picking up some proper cutting fluid for this job; big
drill bits aren't cheap!

Jon