A lathe would make quick work of it, and a pretty job, but you could always just hack off a short piece of 1 inch aluminum or plastic and hand tap a 5mm hole in one end for a long set screw.

EDIT: recalculating...

...provided you already have the tap, tap drill, and a material, that would be cheap and easy. If you had to shell out a few bucks for each of the tools and pay the cut fee for a PITA little purchase at a local metal supplier, you might as well throw in an extra nickle and pay the exhorbitant price for that nicely finished Pauls piece. Maybe there`s a common PVC or ABS size in your local hardware store that just needs a cap glued on and a simple bolt hole drilled through said cap?