3" Sanding drum - runout problem

[Gary McNair]

I use a 3" sanding drum often in my Delta drill press. I know the drill press doesn't have any radial run out - at least not visible. The 3" sanding drums currently available amount to a thick wall rubber tube w/ end plates that are compressed by screwing the mandrel together, then chucking one end of the mandrel shaft into the chuck. I cannot get away from this setup having an inordinate amount of radial run out which makes for a poor sanding experience. I've tried minimum thread pressure on the plates and have rotated the plates. Can't seem to lick the problem.
Many years ago my dad had a solid 3" drum made of rubber doughnuts - that worked sweet - does anyone know if this type of solid drum is available?
Thanks,
Gary

[Josiah Bartlett]

You could try cutting down an oscillating spindle sander mandrel, those are usually a bit higher quality... or, Harbor Freight's benchtop OSS is on sale right now for $129, and I've seen coupons for $99. Its a decent little machine, and the biggest mandrel it comes with is 3".