What is a Torque Wrench?

A torque wrench is a hand tool used to for tightening such as a nut, bolt, or srew.  They are mainly used where the tightness of screws and bolts is crucial. 

The reason torque wrenches are used is so the fastener or fasteners used are tightened for maximum holding power and will not be over tightened. Proper torque ensures the fastener will not come loose, break during tightening, damage threads, warp, or crush the object being so fastened. A torque wrench should be used when assembling most things because we can not judge the amount of torque we apply to it. Nowadays there are many types of torque wrenches, manual torque wrenches that bend and has a gauge and a pointer, click torque wrenches that can be adjusted to click at the desired torque, and digital electric torque wrenches which display the torque on a readout and could be part of automation.

Uses of Torque Wrench

A torque wrench is mainly used to tighten a bolt or a nut type fastener with a specific amount of force. Many such Fasteners on automobiles should be tightened using a torque wrench to the particular amount of force to ensure that the Fastener neither comes apart by itself nor is it over tightened and possibly stressed such that it will break during use. Lug nuts that hold a tire and wheel on the car should always be tightened with a torque wrench and then retightened with the torque wrench after the car is driven to 10 miles.

Types of Torque Wrench

1) Beam-type: A pointer beam is attached to the wrench head. As the wrench itself is "twisted" the beam stays in place, and the scale beneath the pointer moves to indicate the amount of torque, being applied.  

2) Dial Indicator: A simplified beam-type, with a dial attached to the case of the wrench, to indicate the amount of twisting the torque wrench handle is going through.

3) Clicker-type: This unit has a spring-loaded lever, which can be adjusted by twisting the handle to the desired torque reading. 

4) Torque Sticks: These are small torsion bars, inserted between an air wrench or hand air wrenches. and a socket. Each torsion bar has it's own twist setting, and when used, will "bounce-back" the socket, instead of tightening it any further.