Wheel type must match the machine. Flat type 1 wheels are for cut-off saws and angle grinders used in a straight cutting orientation. Type 27 depressed-centre wheels can be used for both grinding and light cutting but are not a substitute for a proper cut-off wheel. Reinforced wheels have fibre glass mesh and are required on high-speed machines.
Thickness trades speed against durability. Thin wheels (1/16 in and under) cut fast with less material loss and less heat, but they are fragile and will break if twisted. Thicker wheels last longer and tolerate more side load but cut slower and remove more material.
Maximum RPM and diameter must match the machine and its guard. A 14 in chop saw wheel runs at lower RPM than a 4.5 in angle grinder wheel and the two are not interchangeable. Abrasive type matters too — aluminium oxide for general steel, zirconia and ceramic for stainless and hard alloys, and specific formulations for non-ferrous metals that would otherwise load the wheel.
