Lets hear some different techniques of repairing a loose arbor.
The rear of the arbor has a tapered seat the contacts a taper in the recoil shield. You can machine the taper on the arbor so it seats tight with an additional half turn. Getting the wedge slot in the arbor in perfect perpendicular position takes careful measuring. This method moves the wedge slot back in relation to the barrel lug and shortens the arbor. Welding the arbor end, then refitting adds considerable labor, plus you need a lathe and welding equipment. I think this gives you the best repair, but requires the most in equipment and labor, I know most don't have a lathe and mig/tig welder in their shop.
I have drilled the pin at the rear of the recoil shield and tapped it for a set screw. If the threads in the frame are not damaged that seems to be a good fix.
Lets say you have a brass frame that the threads have been damaged. Has anyone used Devcon or possibly soft solder to fill any void in the threaded area?
Any other ideas lets hear them.