Rule 123. A guard on a right angle head or vertical portable grinder shall have the guard located so as to be between the operator and the abrasive wheel during use (see figure 3 of R 408.10198 and table 2 of R 408.10199). A portable grinder using a depressed center wheel shall have a guard as prescribed in figure 4 of R 408.10198 and table 3 of R 408.10199.
Mich. Admin. Code R. 408.10123