All mechanical torque wrenches are calibrated from 20% to 100% of full scale, therefore, they should never be used below or above those limits
To determine which torque wrench capacity is best suited for an application, many factors must be considered. However, as a recommendation, use a torque wrench in the middle 50% of the overall capacity of the tool. This will result in longer tool life, ease of use for the operator and increased accuracy from "clicker" type torque wrenches
Always grasp handle firmly in the center of the grip
Approach final torque slowly and evenly
Stop pulling wrench immediately when target torque is reached
Never use a torque wrench to break fasteners loose
Should be cleaned and stored properly
Should always be stored at it's lowest torque setting
Wrenches should be re-calibrated if dropped. Should never be used in excess of it's capacity
Torque wrenches should be "exercised" a minimum of three times at 100% of full scale before use
The wrench selected should be calibrated in the same torque units that are specified
Use of a "cheater bar" will result in an inaccurate reading and can possibly damage the wrench
Torque wrenches will last longer if reasonable care is taken. Always unwind handle to the lowest setting after each use. Do not attempt to lubricate the internal torque mechanism. Clean torque wrench by wiping, do not immerse. The wrench should be sent to a qualified calibration lab once every year or every 5000 cycles for re-calibration
