Tools - Hand Tool Design and Selection Guidelines

Following are a set of guidelines for Hand Tool Design and Selection

• Design the grip to keep the wrist in a neutral position.

• Handles for two handed tools should be located 120° apart and suitable for both left and right handed combinations.

• Keep tool weight to the necessary minimum.  Suspend or counterbalance heavy tools (preferably anything over 1 pound; consider air lines and power cords in the tool weight).

• Definitely suspend any tool system weighing more than 4.5 pounds.

• Design tool balance so the grip is near the center of gravity.

• For gripping tools that operate on closure, such as pliers, use a light spring to return the tool to its open position.  The initial grip span should be 2½ to 3½ inches.

• If the grip must transmit a push/pull force, consider a change in cross-section of diameter along the length of the grip, a hilt, a pommel, or a T-handle.

• Use 2 or 3 finger triggers for power tools.

• Avoid thumb triggers.

• Choose tools with handles that have added friction such as compressible rubber or closed-cell foam, with slightly etched surfaces.

• Handles should be 4½ to 5½ inches long.  Add ½ inch length minimum for gloves.

• Choose tools with a 1¼ to 1¾ inch handle diameter.  For precision operations, use 0.3 to 0.6 inches.

• Pistol grip tool handles should have a flange to prevent the fingers from slipping off.

• Tool handles should not have finger grooves.

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