Section R. 408.10104 - Definitions; M to RRule 104.
(1) "Masonry cutting" means the cutting off, notching or slotting of units of materials such as brick, tile, block or refractory shapes where the workpiece is brought to the machine.(2) "Mounted wheels" means various shaped abrasive wheels not more than 2 inches in diameter and mounted on a plain steel mandrel.(3) "Off-hand grinding" means the grinding of any material which is held in an employee's hand.(4) "Portable grinding" means a grinding operation where the machine is designed to be hand-held and may be easily moved from 1 location to another.(5) "Precision grinding" means the grinding operation performed by machines used to finish work parts to specified dimensions and finish requirements.(6) "Revolutions per minute--rpm" means the number of complete turns that a grinding wheel makes in 1 minute.Mich. Admin. Code R. 408.10104