Automotive Torque Wrenches
When you need precision ratcheting, a torque wrench is the proper tool. Torque wrenches are broken down into four main types based on how they work. Each type is specialized to be better at a certain task, so knowing your types can help you choose the right one for your job.How do torque wrenches work?
A torque wrench works by signaling to the user or stopping the application of force once a certain amount of torque is being applied by the wrench. It allows precision ratcheting of nuts and bolts, such as those on tires or in car engines. The torque is what wrenches automotive bolts from their nuts. The way a torque wrench works is determined by its type.Why would you need a torque wrench?
Torque wrenches were originally invented to prevent over-tightening of bolts in water works. However, they've grown to be increasingly important in automobile and machine maintenance as engineering technology improves. They can be used for a range of tasks, such as the following:
- Replacing and rotation of tires
- Tightening lug nuts, caliper bolts, and head bolts
- Installing lift kits
The different types of torque wrenches are the following:
- Beam type torque wrench - As you ratchet this type of torque wrench, a beam floats along a dial to indicate the force applied.
- Dial indicator torque wrench - Similar to a beam type, an indicator spins around a dial to indicate the force being applied as you are ratcheting the wrench.
- Clicker type torque wrench - This type operates by making a clicking sound once a pre-set amount of force has been applied.
- Torque sticks - These are used with an air wrench to limit the amount of force that can be applied. You'll likely need a set, since each stick sets one limit on the torque that can't be adjusted.
Torque is a measurement of resistance to movement, usually in pounds per foot, caused by friction. Even experienced mechanics are not as accurate at measuring torque as a torque wrench because many factors influence the amount of friction. The factors are the following:
- Surface finishes
- Thread condition
In general, torque wrenches should be calibrated at least once a year to ensure their accuracy; however, it does depend on how often and how aggressively the wrench is used. Typically, you want to have it calibrated after 2,500 repetitions. The more you use it, the more frequently it will need to be calibrated. This calibration should be done by a professional since errors can make the wrench useless. A calibration checks a torque wrench's accuracy and makes adjustments if it has decreased.