Preset Torque Wrench

Although very uncommon in the maintenance shop or home mechanic's toolbox, preset torque wrenches are very common in the automotive parts and assembly industry. Also called "click wrenches" and "reset wrenches," a preset torque wrench is built specifically to provide one torque value and be used applying (or quality assuring) that torque repeatedly.

How the Preset Wrench Works

Nearly all preset torque wrenches work in the same way. The wrench is a long bar with a handle at one end and a socket to which a socket head, open wrench, or other bolt-specific drive is added. The wrench is pre-set for a specific torque. When applied, that torque setting causes the wrench to "click" and break away (loosen the handle from the head) for a given amount of "play." This lets the user know that the specified torque has been reached.

In assembly applications, this means the operator will tighten the fastener using the wrench until the wrench clicks and breaks, then move on to the next fastener or application.

In quality assurance, this means the QA checker will apply force to the fastener and if it breaks without turning, it's approved.

Benefits of the Preset Wrench

The primary benefit of the preset wrench is that it's gauged specifically for a given application and so in assembly line operations, it's very easy to deploy. It also resets quickly with most designs, so repeated use is easier on the operator.

Preset wrenches also tend to be somewhat more accurate than their adjustable counterparts and rarely have failure or loss of accuracy over time. The wrench can also be made application- and operator-specific to improve reliability and ergonomics.

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