Is 0.065 inch (1.651 mm) steel thick enough for tapping? This would be for bolting linear rail onto steel tubing so it would have many bolts and wouldn't be subject to a whole lot of force.
I assume you cant use nuts and bolts. I would highly recommend pop rivets when your working with that thin of a metal, their not as accurate as bolts would be, but pulling the threads will likely happen, as 1,6mm will likely only give you two half threads when tapping. Then use either clamps or a jury rigged jig when you put the two pieces together with pop rivets to ensue no unwanted off-alignment.
