Sometimes “tight is right” is all you need when wrenching in the garage. But some fasteners, like lug nuts, valve-cover bolts or an oil-drain plug, require tightening to the proper torque to prevent stripping threads, warping components or freeing critical parts (like your wheels while cruising down the highway) from your vehicle. For those jobs, you need a torque wrench. And in this post, we show you how to use a torque wrench.
Torque Wrench Types
Torque is simply a twisting force that causes something to rotate. A torque wrench allows you to tighten a nut, bolt or other fastener to a desired torque to prevent over- or under-tightening.
There are several types of torque wrenches, but let’s focus on the most common:
Beam-Style Torque Wrench
This is the most basic design available. It uses a long, flexible beam with a pointer on the end that corresponds to markings on a scale. As you tighten a fastener, the pointer indicates the amount of torque being applied. They provide accurate readings, are easy to maintain and last forever.
On the downside, they’re more difficult to read than modern digital or click-style wrenches. Plus, it can be a hassle to simultaneously apply force to the wrench and keep an eye on the scale if you’re working at an awkward position or in a tight area.
If you’re getting old, like me, you have to fuss with your reading glasses to read the scale, adding another layer of annoyance. Since beam-type wrenches don’t warn you when you’ve reached the desire torque setting with a “click” or “beep,” it’s easy to overtighten a fastener.
Click-Type Torque Wrench
This is probably the most popular choice for DIYers and beginners since it combines affordability with accuracy and ease of use. Bear in mind that you can’t set rolling torque with a click-type torque wrench; a beam or dial torque works great for that. You set the desired torque by rotating the handle until aligning the proper marks on the handle with those on the body of the wrench.
It sounds confusing, but the video here shows how it’s done:
How to Use a Torque Wrench: Setting up a Click-Type Wrench
One of the nice things about a click-type torque wrench is that it makes an audible click when you reach the desired torque. This serves as a red flag that tells you to stop tightening, which helps prevent over-tightening. However, the clicking sound doesn’t prevent you from continuing to apply force, so the key is to stop tightening as soon as you hear it.
Digital-Type Torque Wrench
This is the most accurate type, hence the most expensive.
Most models allow you to preset multiple torque settings and retain settings as you use it, enhancing convenience. Once you reach the desired torque setting, the wrench warns you with a beep, buzz, flashing light, vibration or some combination thereof. Their advanced notification settings help you prevent over-tightening.
Digital wrenches require batteries and can be sensitive to use, so keep that in mind.
There are other types of torque wrenches, like the slip-type, split-beam type and deflecting-beam type, but the few listed here are the most common and will suit the typical DIYer just fine.
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Torque Wrench Maintenance & Use Tips
• Avoid dropping it – or throwing it when you’re frustrated. A minor accidental drop is probably fine, but avoid tossing your torque wrench into the back of your truck or on the floor. Doing so can affect the calibration.
• Use the case – Most torque wrenches come with a plastic case. Use it to protect against moisture and damage.
• Loosen click-type wrenches before storage – This relieves pressure from the internal spring, which helps preserve the proper calibration.
• Don’t use your torque wrench as a breaker bar or ratchet – A long-handled, 1/2″-drive torque wrench may look like a breaker bar, but it’s a precision tool, so treat it that way to maximize its life. Also, tighten fasteners with a ratchet until snug, and then use the torque wrench to finish the job.
• Check calibration yearly – This helps ensure the wrench provides accurate readings. A quick online search will yield places where you can ship a torque wrench for calibration. You can also do it yourself with a little Internet research.
• Use high-quality extensions – If you must use an extension to reach an out-of-the-way fastener, use thick, high-quality extensions that resist twisting. Avoid using swivel extensions or other types that have a lot of play in them since that can affect your reading.
What Torque Wrench Should I Get?
In my opinion, a DIYer can’t go wrong with a click-type wrench. They’re affordable, accurate and simple to use. You can get them in 1/4″, 3/8″ and 1/2″ drive. A 1/4″ drive wrench measures in inch-pounds and is used for small fasteners. The 3/8″ and 1/2″ wrenches measure in foot-pounds, with the 1/2″ wrench usually going up to 150 ft. lbs. That’ll take care of most fasteners you need to tighten.
Now that you know how to use a torque wrench, add one to your tool collection and start using it.