Cup Wheels & Hand Grinding

We stock 4", 5", 6" and 7" cup wheels. The wheel has to match your grinder's guard size and arbor, not just its motor: a 7" wheel will not fit inside a 5" guard. Most 4-1/2" to 5" hand grinders take a threaded 5/8"-11 wheel, while 7" grinders and larger machines usually run a 7/8" - 5/8" arbor. If you tell us your make and model we will confirm the fit before you order.

A threaded wheel screws directly onto the grinder's 5/8"-11 spindle, so no flange or nut is needed and the wheel cannot slip. A non-threaded wheel has a plain 7/8" - 5/8" arbor hole and mounts between the machine's flanges. They are not interchangeable, so check which one your grinder uses before ordering.

16 grit is the aggressive choice for knocking down high spots, leveling trowel marks and removing thick coatings fast. 30 grit cuts slower but leaves a smoother surface, so it is the better first step if the slab is going to be polished or coated afterward. Many crews run 16 grit to level, then 30 grit to refine.

The rule is the opposite of what most people expect: soft bond for hard concrete, hard bond for soft or abrasive concrete. A soft bond wears away faster, which keeps exposing fresh diamond so the wheel keeps cutting hard aggregate. On soft or green concrete, a hard bond stops the wheel from wearing out prematurely.

Use a PCD (polycrystalline diamond) wheel rather than a standard segmented wheel. PCD shears sticky coatings off the slab instead of loading up with them, which is what causes a normal diamond wheel to glaze over and stop cutting. Follow the PCD pass with a 16 or 30 grit cup wheel to clean up the surface.