What is a torque wrench?

If you’re an advanced do-it-yourselfer or just someone who wants to become more handy and independent at home and on the job, you’ve probably heard of the torque wrench and want to learn a bit more about it. While torque wrenches were invented by Conrad Bahr in 1918, unless you work in a field where they are commonly used, you’ve probably never even seen one, let alone had the opportunity to use one. You may only know about them in theory. But, as they are a highly practical tool that does have a significant applicational value, at least a basic understanding of torque wrenches is an important bit of knowledge to have in your arsenal, if you ever think you might need it.

Torque wrench basics

The torque wrench gets its name from its most basic function: It’s a wrench that measures torque. You may be asking why a wrench needs to be able to measure torque at all, but to answer that question, consider applications in which it’s important have proper tension on nuts and bolts, like plumbing. For any application where precise tension matters, you need to be able to measure it to ensure that the bolt is properly fastened—that’s where a good torque wrench comes in. A properly calibrated and standardized torque wrench will allow you to fine-tune the torque you’re applying to your nut or bolt to ensure the right level tension is applied.

Types of torque wrenches

There are several different types of torque wrenches; the more precise your needs are, the more accurate and standardized your torque wrench needs to be. For readability and practicality, this is an abbreviated overview of the most common torque wrench types you will come across. More—especially earlier generation—varieties exist.

  • Beam-type torque wrench: Conceived and invented by William Percy Chrysler in the late twenties, it capitalizes on Hooke’s Law for accuracy, by using two beams: A lever beam and an indicator beam. Though highly effective for basic use, it’s not recommended for precision application due to lack of standardization and the availability of preferable modern variations.
  • Click torque wrench: The click torque wrench uses a calibrated clutch system to preset torque. This gives the user more control than older torque wrench types. It’s also easier for folks to learn to use because you can both hear and see when desired torque is achieved.
  • Electronic torque wrenches: There are a few advantages to getting an electronic torque wrench. For one thing, there is the clear display (usually LED), which shows you exactly what’s happening. Secondly, specific torque values can be programmed as presets for specific applications, removing on-the-spot guesswork. Because of this, you, your boss, your clients—everyone involved in your work process knows exactly what settings were used so there can be no question that you completed the application using standardized procedure. Even better, it can be interfaced with your PC.
  • Click-electronic hybrid torque wrench (aka mechatronic torque wrench): This is a handy combination featuring all the benefits of both electronic and click torque wrenches.
  • Hydraulic torque wrenches: Hydraulic torque wrenches are used mainly in factories and other industrial settings both due to their extreme high torque capacities and the fact they tend to be more appropriate for larger applications as a result.