WAC 296-807-18025. Use specific safety guards for vertical and angle grinders using Type 6 or Type 11 wheels

(1) You must make sure the safety guard: (a) Covers the wheel's plane of rotation toward the operator for at least one hundred eighty degrees; (b) Covers the side of the wheel toward the driving flange for at least one hundred eighty degrees; (c) Has a skirt which is adjustable to within one-eighth inch of the plane of the surface of the wheel. (2) You must make sure not to use a "revolving cup guard." Note: "Cup back bushings" do not substitute for safety guards.