If you start with a pilot hole you can use a down spiral roughing bit
that will shove the swarf out the bottom, MUCH easier to see what is
going on.

But someone else mentioned water jet, the only way to go.

Ken Sterling 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

You may want to make a template, then use (since you are a woodworker)
a hefty router with the proper bit (carbide tipped) and run the router
around the inside of the template, increasing depth over 3 or 4
passes. A router *will* cut the aluminum and 3/4 depth isn't all that
much. HTH
Ken