For my day job I build machines. Most of the machines I build or repair use a lot of 2" square tube for their frames. During the course of my day I have to add a lot of holes to the frames. Typically for hanging wires or airlines. I'd say more than 75% of the time, I'm drilling on the centerline of the tube. Most of the remaining time I'm probably going to place a hole at 1/2" from the edge.
Laying out these holes with a standard square actually lends itself to a lot of error. You can be off by over 1/16th of an inch. In all honesty, for mounting a wire hanger, that's good enough. I'm anal about things like that...so...a new tool needed to be made.
|Using a 1/4" transfer punch, I can accurately locate a hole on the centerline of the tube, or 1/2" from the edge.|
|The large surface of the short leg overcomes the problems presented by the radiused corner of the tube. I can repeat the measurement over and over.|