Hi,
OK I have very quick but ugly drawing for you. : )
I have 50x20mm steel bars for the rail. I'll get them pre-drilled for the rails. BUT I'll also weld some bolt like metals to them for better holding/rigidity. These bolts will be covered with EG.
My question is will the bars get bent after heat treatment (for stress relieving)? If yes then the alignment of the holes will also be circular and the rails wont get bolted to the bars.