Quick Facts on Torque Wrenches

Quick Fact: The first Torque Wrench was invented by Conrad Bahr in 1918 while working for the New York City

Water Department. It was designed to prevent overtightening bolts on water main and steam pipe repairs

underground.

PROPER TORQUE WRENCH USAGE

• Always hold handle in the center of the grip. • Wrench should be tested if dropped.

• Approach final torque slowly and evenly. • Should never be used in a “breakaway"

situation.

• A wrench’s “sweet spot" is between 40-80% of maximum capacity. • Most types should be "cycled" before use.

• The wrench selected should be scaled in the same torque units

that are specified.

• Should never be used in excess of its capacity.

• Calibrate once per year or every 5000 Cycles per ASME

PROPER WRENCH SELECTION

Proper wrench selection is just as important as the wrench itself

• The more critical the torque requirement, the more accurate (think electronic) the wrench should be.

• Choose a torque wrench that has roughly twice the capacity of the torque being applied. For example, for an

application of 100 k.lbs., choose a 200 k.lbs. wrench. If a 200 ft.lb. wrench is not available, then a 250 ft.lb. would

work as well. The “sweet spot" of a torque wrench is between 40% and 80% of the maximum scale (for a

250 ft. lb. wrench, between TOO and 200 It. lbs).

• Avoid selling a wrench that wi\\ be used at the bottom of the scale and at the top of the scale. Mechanical torque

wrenches are typically calibrated from 20% to 100% of full scale.

TORQUE WRENCH CARE

• Always wind down Micrometer wrenches to lowest setting for storage.

• Wipe clean with soft cloth.

• Store in its case with desiccant pack and manual.

• keep in a cool, dry place.