• Several types of hand-held power tools need to have a constant-pressure switch or one that shuts off power when pressure is released, including drills, grinders, saws, and others.

The following hand-held power tools must be equipped with a constant-pressure switch or control that shuts off the power when pressure is released:

• Drills;
• Tappers;
• Fastener drivers;
• Horizontal, vertical, and angle grinders with wheels more than two inches in diameter;
• Disc sanders with discs greater than two inches;
• Belt sanders;
• Reciprocating saws;
• Saber saws,
• Scroll saws, and jigsaws with blade shanks greater than one-quarter inch (0.63 centimeters) wide; and
• Other similar tools.

These tools also may be equipped with a “lock-on” control, if it allows the worker to also shut off the control in a single motion using the same finger or fingers. The following hand-held power tools must be equipped with either a positive “on-off” control switch, a constant pressure switch, or a “lock-on” control:

• Disc sanders with discs two inches or less in diameter;
• Grinders with wheels two inches or less in diameter;
• Platen sanders, routers, planers, laminate trimmers, nibblers, shears, and scroll saws; and jigsaws, saber and scroll saws with blade shanks a nominal one-quarter inch or less in diameter.

The constant-pressure control switch should be regarded as the preferred device. Other hand-held power tools such as circular saws having a blade diameter greater than two inches (5.08 centimeters), chain saws, and percussion tools with no means of holding accessories securely must be equipped with a constant-pressure switch.