Ned Simmons wrote:

Unless you're using existing fittings that require the 1" holes, I'd
reduce their diameter. As a point of reference, I recently had to look
at #80 roller chain for lifting service. The chain pins are 5/16"
diameter; its minimum tensile strength is 12,500 lbs. The pins are in
double shear (two shear planes) and made of alloy steel, but you get
the picture.

If you're stuck with 1" holes, I second the hole saw.

Hi Ned, and thank you for your reply. I actually noticed the same thing the
other day when I looked at the pin on my ball mount (it's a 5/8" pin in a
2"x2" piece of square tubing).

The difference, however, is that the ball mount tubing is 3/32" thickness,
instead of the 1/8" thickness of the 3x3 I will be working with. While I
would likely agree with you that it would be sturdy enough for my intended
usage, I will still be using one-inch holes in 3x3 tubing, for no other
reason than to give myself a little extra cushion for the pushin (and to
help compensate for my lack of perfect weldments, et cetera).

Also, thanks for the suggestion about the hole saw.

Jon