30 CFR § 57.14115
Stationary grinding machines.
Stationary grinding machines, other than special bit grinders, shall be
(a) Peripheral hoods capable of withstanding the force of a bursting
wheel and enclosing not less than 270°--of the periphery of the wheel;
(b) Adjustable tool rests set so that the distance between the
grinding surface of the wheel and the tool rest is not greater than 1/8
(c) A safety washer on each side of the wheel.
[53 FR 32528, Aug. 25, 1988; 53 FR 44588, Nov. 4, 1988]