(By authority conferred on the director of the department of energy, labor and  
economic growth by sections 16 and 21 of 1974 PA 154, and Executive  
Reorganization Order Nos. 1996-2, 2003-1, and 2008-4, MCL 408.1016, 408.1021,  
445.2001, 445.2011, and 445.2025)  
R 408.10101 Scope.  
Rule 101. This part sets forth rules and specifications for the safe use of abrasive  
wheels in, around and about places of employment. They include specifications for  
safety guards, flanges, chucks and rules for storage, handling, mounting and use of  
all grinding wheels, except natural sandstone wheels.  
History: 1979 AC.  
R 408.10102 Definitions; A to C.  
Rule 102. (1) "Abrasive wheel-wheel" means a cutting tool that consists of abrasive  
grains held together by a bonding material.  
(2) "Blotter" means a flat disc of compressible material that is used to cushion the  
area of a grinding wheel coming in contact with a flange.  
(3) "Centerless O.D. grinding" means the precision grinding of the outer surface of  
any cylindrical workpiece which is rotated by a regulating wheel and supported by a  
work blade.  
(4) "Concrete sawing" means the cutting or slotting of materials such as concrete  
or asphalt where the sawing machine rides upon the surface being sawed.  
(5) "Contour grinding" means a grinding operation in which the grinding wheel or  
part follows a machine-generated contour.  
(6) "Cutting off" means the slicing or parting of any material or part.  
(7) "Cylindrical O.D. grinding" means the precision grinding of the outer  
surface of any cylindrical workpiece which is supported at one or both ends.  
History: 1979 AC; 1990 AACS.  
R 408.10103 Definitions; D to L.  
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Rule 103. (1) "Disc or plate-mounted grinding" means the removal of material  
using an abrasive wheel fastened to a metal plate.  
(2) "Flange" means a collar, disc, or plate between which abrasive wheels are  
(3) "Form grinding" means to impart a specific shape or form onto a grinding  
wheel for the purpose of grinding that specific shape to the material or workpiece.  
(4) "Guard" means an enclosure that is designed to restrain pieces of abrasive  
wheel and protect the employee if the wheel breaks.  
(5) "Internal grinding" means the precision grinding of the inside surface of the  
hole in a workpiece.  
(6) "Lapidary" means to cut off, shape, or grind precious or semiprecious  
gem-like materials.  
History: 1979 AC; 1990 AACS.  
R 408.10104 Definitions; M to R.  
Rule 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.  
History: 1979 AC.  
R 408.10105 Definitions; S to W.  
Rule 105. (1) "Shoulder grinding" means a periphery grinding operation where a  
limited amount of grinding with the side of the wheel may be performed.  
(2) "Snagging" means the grinding which removes relatively large amounts of  
material without regard to close tolerances or surface finish requirements.  
(3) "Surface feet per minute" or "sfpm" means the distance in feet that any 1  
abrasive grain travels in l minute on a peripheral surface of a rotating grinding  
(4) "Surface grinding" means the precision grinding of a plane or formed surface.  
(5) "Tool or cutter grinding" means the precision grinding or sharpening of various  
types of cutting tools.  
(6) "Tuck pointing" means the removal, by grinding, of mortar, cement, or other  
nonmetallic material.  
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(7) "Wheel types" means the classification of abrasive wheels as listed in the  
following order:  
Type 1 – Straight wheel  
Peripheral grinding wheel having a diameter thickness and hole.  
Type 2 – Cylinder wheel.  
Side grinding wheel having a diameter, thickness and wall — wheel is mounted on the diameter, or a  
similar wheel mounted in a chuck or on a plate.  
Type 5 – Wheel, recessed one side.  
Peripheral grinding wheel having one side straight or flat and the opposite side recessed.  
wheel allows a wider faced grinding wheel to be used when the available  
mounting thickness (E) is less than the required overall thickness (T).  
The recess allows grinding clearance for the nut and flange.  
A recessed  
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Type 6 – Straight-cup wheel.  
Side grinding wheel having a diameter, thickness and hole with one side straight or flat  
and the opposite side recessed. This type, however, differs from Type 5 in that the grinding is performed  
by the wall (W). The wall dimension (W) takes precedence over the diameter  
of the recess as an essential intermediate dimension to describe this shape type.  
NOTE: Arrows indicate grinding surface.  
Type 7 – Wheel, recessed two sides.  
Peripheral grinding wheel having both sides recessed to allow grinding clearance for both flanges or  
recessed so that an unusually wide faced wheel may be mounted when the available mounting thickness  
(E) is less than the overall thickness (T).  
Type 11 – Flaring-cup wheel.  
Side grinding wheel having a wall flared or tapered outward from the back. Wall thickness at the back is  
normally greater than at the grinding face (W).  
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