Section R. 408.41933 - Portable powered tools; controlsRule 1933.
(1) A hand-held powered circular saw which has a blade diameter of more than 2 inches; an electric, hydraulic, or pneumatic chain saw; and a percussion tool without positive accessory holding means shall be equipped with a constant-pressure switch or control that shuts off the power when the pressure is released. A gasoline-powered, hand-operated tool shall be equipped with a constant-pressure throttle control. A throttle position lock may be provided for starting only.(2) All of the following tools shall be equipped with a constant-pressure switch or control and may have a lock-on control if the tool can be turned off by a single motion of the same finger or fingers that turn it on without release of the grip on the tool: (a) A hand-held powered drill.(d) Grinder with a wheel more than 2 inches in diameter.(e) Disc sander with a disc more than 2 inches in diameter.(j) Jigsaw with a blade shank more than a nominal 1/4 inch.(k) Similarly operating power tool. The lock-on control of a drill of more than 3/8-inch capacity shall not be used when the drill is held in the hand to drill, clean, or enlarge a hole.
(3) All of the following hand-held powered tools may be equipped with either a positive on-off control or other control as prescribed in subrules (1) and (2) of this rule: (b) Grinder with a wheel 2 inches or less in diameter.(c) Disc sander with discs 2 inches or less in diameter.(k) Jigsaw with a blade shank of nominal 1/4 inch or less.(4) The operating control on a hand-held power tool shall be located so as to prevent accidental operation.Mich. Admin. Code R. 408.41933