Ball casters like these ones from ACME Caster Company are supposed to work well on cement floors — mount ’em to your project and they’ll roll easily in any direction — but we’re skeptical about using these in the shop because dirt, dust, and metal filings just can’t be good for ’em. If you don’t need casters, you could also mount these upside down as ball transfer units for custom out-feed work supports.
Small balls transfer the load from large ball to the seat to provide even load distribution and minimal surface contact. ACME Caster Company manufactures all the components from carbon steel. They harden the balls and seat for long wear life, and they treat exposed surfaces so they’ll resist corrosion. They finish the seat in black and the large ball in chrome.
Rockler sells these ball casters in three weight ratings, 100 lbs, 150lbs, and 250lbs, in either stem or plate-mount. The most expensive set of four casters is the 250lbs stem-mount casters, which’ll run you $36 — prices for the other casters go down from there.