R 408.10141 General requirements.

Rule 141. (1) An abrasive wheel shall be mounted between flanges, except as noted below, which shall not be less than 1/3 the diameter of the abrasive wheel. Exceptions: (a) Mounted wheel. (b) Portable cup, plug and cone wheels with threaded inserts or studs. (c) Abrasive disc of the inserted nut, inserted washer and projecting stud type. (d) Plate mounted wheel. (e) Cylinder, cup or segmented wheel mounted in a chuck. (f) Depressed center wheel. (g) Internal wheel less than 2 inches in diameter. (h) Straight and flaring cup wheel for terrazzo use. (i) Cutting-off wheel (see subrule (2)). (j) Masonry and concrete saws. (2) A straight cutting-off wheel shall be mounted between relieved flanges which are not less than 1/4 the wheel diameter. A depressed center cutting-off wheel more than 16 inches in diameter shall be mounted between flat unrelieved flanges not less than 1/4 the wheel diameter. (3) A masonry saw using a reinforced resinoid and steel-centered wheel may use 4-inch diameter flanges for wheels through 20-inch diameter. (4) Concrete saws using a steel-centered wheel 20-inch and larger may use flanges 1/6 the wheel diameter.