Have been thinking about mounting linear rails to steel square tube.
Does everyone rely on the thickness of the tube being enough to tap threads into or are other methods used.
I know I could weld some flat bar on top of the tube and get that machined flat.

I was wondering if anyone has used Rivet Nuts?
I would think they would be alot quicker than tapping a million threads in the tube.
I would counter bore the tube to allow the Rivet Nut to sit flush with the top of the tube.

Good idea or a waste of time?

Know a better way?

Steve