If you have a boat trailer or have changed the spare tire on your car, a torque wrench is a required tool and is simple to use . Most people believe that "the tighter the better" is the way to go. Your average person will simply grab an impact wrench and tighten away. This is not the correct way to apply torque to your wheels or other critical fasteners. Too much torque can add stress to a lug nut and cause it to shear off. Also with head bolts, the torque on those bolts determines the amount of clamping force on the gasket. Over tightening those bolts can crush the gasket or distort the metal. The better way to apply the correct amount of foot pounds of torque is to use an accurate torque wrench.
There are several different types of torque wrenches available out there. One type is the torque wrench with a dial indicator built into it. The dial indicates how many foot lbs of torque is being applied. Dial types are generally more accurate and easier to read. This model is generally the choice of professional mechanics where accurate measurement is necessary. The dial indicator is more precise and is easier to read. Some are available with a light or buzzer to indicate when a preset torque value is achieved. Another variation is the clicking type torque wrench. These are probably the most popular and readily available. This torque wrench makes a clicking sound when the preset torque is reached. This lets you know to stop applying force to the nut you are fastening and move to the next one. For most uses, these type of wrenches work just fine and are rugged and easy to use. For the person who always the latest gadget, there are LED and LCD models available as well. The display shows the precise foot lbs of torque. These can usually switch between SAE and Metric as well. For most garage mechanics and home owners, the clicking type torque wrench is the best choice.
Just remember to always check the manufacturer's specs for the recommended torque. Next time, you need to tighten the nuts on your boat trailer, put down the impact wrench and grab a torque wrench.