Wild_Bill wrote:
Doing layout work on square tubing is easy. You need a decent
machinists square and a scribe.

When you mark the location of a hole on one side, set the square with
the straightedge perpendicular to the length of the tubing on the
first mark, and scribe around to the opposite side.
When the line is scribed all the way around, the ends will meet if
some attention is expended during the exercise.

With a little care, the holes on opposite sides of the tubing should
be within/less than .010" difference. That will probably be as close
as just drilling thru the tubing can attain.

Thanks Bill, I appreciate it. This project will be a good exercise for me
to work out layout and indicating for me. I have seen how indicating is
done with an X-Y table, but I have always had a tricky time lining things up
when the table is not adjustable with such precision, as is the case with my
drill press. What I end up doing is setting up the clamping to be not quite
as tight as I need it, then gently tapping until everything is lined up. I
don't know if there is a better way to do that outside of a proper X-Y
table.


It's a good practice to pilot drill holes with a 1/8" split-point
drill for holes of 1/2" or larger.
When the layout work and the pilot holes are placed accurately, the
larger holes are generally (nearly) perfectly located, and cut
substantially faster.

Ah, thanks, that is an excellent suggesiton. Pre-drilling both sides with a
small hole would make it a breeze to punch through both sides with the big
drill.

I will definitely keep my eye out for a split-point collection.

It should be obvious that a good cutting lubricant is going to be a
major benefit.
Application of a small amount, as little as a quick swipe, with a
small paint brush (or disposable acid brush) before starting each
hole is generally adequate.
Laboratory wash bottles with a dip tube and an extended spout are a
handy method of applying cutting lubricant for drilling, milling,
sawing and turning on a lathe.

I picked up a little bottle of RapidTap yesterday from the local tool shop.
I guess it's high time I started to treat my operations as actual
metalworking.

Thanks again Bill,

Jon