Astro Pneumatic AST219 ONYX 3pc Die Grinder Kit w/ 1/4" 90 Angle Die Grinder 1/4" Die Grinder 8pc Rotary Burr Set. Sold by Mechanics Tools Warehouse. add to compare compare now. CarbideBurr SL4 Carbide Burr Die Grinder Bit Double Cut. Sold by clickhere2shop.