On Fri, 23 Apr 2010 21:58:43 -0700, "Jon Danniken"
wrote:

Howdy,

I am building a half-rack squat rack for weightlifting. For a conceptual
reference, here is a picture of one particular commercially available unit:
http://i42.tinypic.com/2e3rcdc.jpg

For my version, I am using 3"x3" square steel tubing with an 11 gauge
(~1/8") wall thickness. The vertical members will be drilled through in a
couple dozen locations (for mounting the bar holders and safeties to), each
to a diameter of one inch.

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.

--
Ned Simmons