What to consider when buying a torque wrench
It’s important that you choose the right torque wrench for the job at hand – or the applications that you anticipate using it for – or you run the risk of damaging the fastener socket. You can determine the best torque wrench for a task by looking up the torque specifications for a particular nut or bolt. These may be listed in the machine’s manual, or can be found online, and will usually be expressed as foot-pounds.
Torque wrenches are either adjustable or pre-set to a specific calibration. Pre-set torque wrenches are suitable for jobs where a single repeated application is required, while an adjustable torque wrench offers the operator the flexibility to set the desired torque value for each application. Adjustable torque wrenches usually express the selected torque value in imperial and metric values on a scale that is either analogue or digital.
Two of the most common types of adjustable mechanical torque wrenches are the dial (also called beam) torque wrench and click torque wrench. The dial torque wrench is easy to set up, simple to operate and requires less maintenance, as well as less-frequent calibration, than a click torque wrench. However, one of the disadvantages of a dial torque wrench is that you have to keep an eye on the scale to determine when the required torque has been reached, which can be hard to do in certain circumstances. The click type torque wrench, on the other hand, will indicate – usually both audibly and tactilely – when the desired torque has been reached so that the operator does not need to constantly watch the display/scale.
Electronic torque wrenches use a strain gauge to measure torque and are more accurate than their mechanical counterparts. Some electronic torque wrenches will record each torque measurement, so that it can be recalled at a later stage. The data collected by the torque wrench can then be used to determine when the tool is being operated incorrectly, as well as when it needs to be re-calibrated.
A torque wrench – whether mechanical or electronic – is a solid investment for any DIY-er, so make sure that you buy a good quality model. It is ideal to buy a torque wrench that comes with a specially designed case, or to buy a case separately for your torque wrench, as this will protect it from damage and de-calibration, which often occur when it is knocked or dropped between uses.