Hey Switch!
Most of the rails I make are used out of the box, a few get blind holes drilled & tapped, and some get cut to length. All are 1/2" & 3/8" dia.
Cutting long pieces in my grinder is a bit of a problem, as it only has a throat depth of 10" or so. That requires I cut on an angle, and then cut again to make it square. It's OK for a hobby shop!

I agree most DIY people don't have lathes, I'd be lost without mine even if it is a Birmingham!

Widgit