Use a hole saw that is 2" diameter. 1. Lay out the holes. 2.Drill small
holes in the corners, maybe 1/16" diameter or smaller. 3. Drill out
the 2" hole.
4. Finish by removing the remaining stock (not much) with an approriate
milling cutter. File corners if you need to.
I had to do this for 14 holes of 3 different sizes (3/4", 7/8" and
1") in 1" thick steel plate once. I used this process, but the
dimensions had to be closer. So I used my shaper with a square,
relieved on all four sides cutter to remove all the remaining material.
Pete Stanaitis
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njrich wrote:

Gentlemen,
Hope you are fine wherever you may be.

I have a job which came my way which calls for making 2"x2" square
holes in 3/4 inch aluminum plate.
I am a construction worker, carpenter, with access to a heavy
mill-drill machine and a small home shop size band saw. I have to make
24 of these square holes in separate 5" x 6" x 3/4" sections. The
tolerances are not tight. + or - .01 inches is ok.

My question is what is the best way to do this? From what I can see
there are three choices.

1. Layout the square, drill a 5/8 hole, put a hacksaw blade through
and start hacking away. Finish off
using an end mill. Of course I might need a new set of arms when I'm
done. i need a new brain already!

2. Due the same but weld the bandsaw blade through each plate and cut
using the band saw before
finishing with the mill.

3. Drill out a square shape formed by a series of holes using a 1/4"
drill bit and finishing with the mill.

My 3 ideas might suggest to you that I have little experience with
machining metal. And that would be
quite true. So I would appreciate your suggestions.


Thanks,
Rich