Guidelines: This checklist covers regulations issued by the U.S. Department of Labor, Occupational Safety and Health Administration (OSHA) under the general industry standards and the construction standards. It applies to fixed and portable abrasive wheel machinery. Natural sandstone wheels and metal, wooden, cloth, or paper discs, with a layer of abrasive on the surface are not covered by this checklist. This checklist must be used in conjunction with the Machines--General Requirements checklist. Definitions of key terms are provided at the end of the checklist. This checklist does not address extensive specifications for design of guards and flanges. Consult the OSHA regulations for additional details.
Definitions: Ring test: The wheels should be tapped gently with a light nonmetallic implement, such as the handle of a screwdriver for light wheels, or a wooden mallet for heavier wheels. Tap wheels about 45¼ each side of the vertical centerline and about 1 or 2 inches from the periphery as indicated by the spots in the figures below. Then rotate the wheel 45¼ and repeat the test. A sound and undamaged wheel will give a clear metallic tone. If cracked, there will be a dead sound and not a clear "ring."
Do grinding wheels fit freely on the spindle?
Is forcing the grinding wheel on the spindle prohibited?
Are all wheels closely inspected and sounded by the user (ring test) to make sure they have not been damaged before being mounted? Note: Before mounting the wheel, make sure the spindle speed of the machine does not exceed the maximum operating speed marked on the wheel.
Is the spindle nut tightened only enough to hold the wheel in place?
Are all abrasive wheel operators required to use eye protection?
Are all grinding machines equipped with sufficient power to maintain the spindle speed at safe levels under all conditions of normal operation?
Are all contact surfaces of the wheel, blotters, and flanges flat and free of foreign material?
When a bushing is used in the wheel hole, is it positioned so it does not exceed the width of the wheel nor make contact with the flange?
Floor and Bench-Grinding Machines
Are all floor- and bench-mounted abrasive wheels equipped with safety guards?
Does the safety guard cover the spindle end, nut, and flange projections?
Is the maximum angular exposure of the grinding wheel and sides 90¼ or less? EXCEPTION: When work requires contact with the wheel below the horizontal plane of the spindle, the angular exposure shall not exceed 125¼. In either case, the exposure shall begin at not more than 65¼ above the horizontal plane of the spindle.
Are work rests provided that are rigidly supported and readily adjustable?
Are work rests kept adjusted closely to the wheel with a maximum opening of 1/8 inch to prevent the work from being jammed between the wheel and the rest?
Portable and Other Abrasive Wheels
Do all machines with abrasive wheels greater than 2 inches in diameter have safety guards? Note: Some abrasive wheels may be equipped with flanges.
Is the maximum exposure angle on all grinding wheels 180¼ or less?
When in use, is the guard on right angle head or vertical portable grinders located between the operator and the wheel?
Is the guard on right angle head or vertical portable grinders adjusted so that pieces of a broken wheel will be deflected away from the operator?
Is the top half of the wheel on other grinders always enclosed?
General Requirements for Guards
Are the guard and its fastenings strong enough to retain fragments of the wheel in case of breakage?
Are guards mounted to maintain proper alignment with the wheel?
Are tongue guards at the top of the wheel of bench, floor stand, and cylindrical grinders adjusted to the decreasing diameter of the wheel so that the gap is never more than one-fourth (1/4) of an inch?