5 Torque Wrench Myths, Tested
Of all the tools in an entry-level DIY toolbox, the torque wrench is the most accurate and the most powerful. Should a torque wrench not do its job, your car could potentially fall apart; alternatively, it might never come back apart without a lot of force. We own a torque wrench so we can have confidence that our projects are assembled correctly. Since a torque wrench is so ubiquitous and important, there is a lot of passionate discussion about the proper care and feeding of this tool—and a lot of the talk is garbage.
There are seemingly endless myths about how a torque wrench works, how it is best used, and how it should be maintained. Some “rules” seem rooted in a deep desire to maximize the accuracy of the tool and minimize potential damage to it. Others simply reflect a misunderstanding of how the wrench works. We know this because Torque Test Channel on YouTube recently grabbed a few torque wrenches and set up a dynamometer to separate fact from fiction.
Torque Wrench Myth #1: A Smooth Swing Matters
In the garage, many activities reward a smooth application of force. When using a torque wrench to put the final tension on a bolt, you are looking for an accurate measurement, and those rarely come with herky-jerky movements. Torque Channel‘s tests reveal that a long, smooth pull does seem to be the way to go, though the rule has its exceptions: While electronic torque wrenches demand a more regimented process, click-type torque wrenches can account for a fair amount of misuse.
Verdict: In general, a smooth swing does matter if your goal is accuracy—and, of course, it is. Otherwise, you’d be using a breaker bar.
Torque Wrench Myth #2: Always Double-Click
A long, smooth pull to final tension, and you let off the pressure. Why not give it a quick check to make sure? A double-click can’t add that much more torque.
The dynamometer tells us that, with a bolt at 100 foot-pounds, that additional click is worth about 1 additional foot-pound. Is that amount likely to make or break a project? Probably not, since a single foot-pound is within the accuracy range of the tool itself.
Takeaway: Since extra clicks can add up, the effect of a confirmation click is something to be aware of, but it is likely not a big deal.
Torque Wrench Myth #3: Recalibrate After Dropping
Use does not have to be synonymous with abuse when it comes to tools. Yes, tools wear out even when used as intended, but how delicate are torque wrenches, really? Torque Channel confirms that a brand-new wrench is working as advertised before subjecting it to a handful of “drops.” Then, the wrench’s calibration was checked—it was unaffected. The wrench was then submitted to additional abuse that honestly made me cringe a little. I’m sure someone has used a torque wrench as a makeshift hammer, but I doubt that person is concerned with the accuracy of the wrench if that is the kind of hackery they engage in.
The wrench was unaffected even by blatant abuse. Of course, this was a click-type wrench, the kind that tends to be more durable. (I would expect a digital wrench to be more fragile.)
Takeaway: If you drop your wrench, and you don’t trust it, there is no reason not to put your mind at ease and recalibrate—just know you probably don’t have to.
Torque Wrench Myth #4: The Warm-Up Period
This one was new to me. Some torque-wrench users use a torque wrench on something like a lug nut or socket clamped in a vise before they use it on the specific item to be final-torqued. The theory appears to be that you should confirm the mechanism is free and working properly, so you aren’t feeling for a click that never happens.
The benefit of this practice turns out to be peace of mind. All the wrenches tested on the dyno, and even those tested on a calibration rig, show that the change between the first and the 10th clicks is well within the tested spec of the wrench.
Takeaway: Not required, but I won’t judge if you keep doing this.
Torque Wrench Myth #5: Store It Slacked
Click-type torque wrenches are pretty simple at the core, with a spring and mechanism that shifts with a certain level of force. That spring is the key to calibration, so keeping it under tension has to be bad for the tool, right? Well, yes. Torque Channel examined a handful of wrenches of various sizes and sources that had been left set and under tension—for many years—and found that they all read slightly off. None, however, were off by a dangerous amount.
Takeaway: Best practice is to remove the tension, but don’t panic if you aren’t already doing it, or if you forget.
Torque Wrench Myth #6: Digital Torque Adapters Are Suitable Replacements
One of the gripes I have with torque wrenches is that I need at least four, and I am really not that far up the food chain, as far as DIY mechanics go. Given the funds I have tied up in my torque wrenches, it is easy to look down on the relatively affordable digital torque adapters. These can be attached to the end of a breaker bar or ratchet and use a transducer and display to show the torque input to the bolt.
Since digital adapters tended to be significantly cheaper than wrenches from known brands, it was only logical to discount their performance. Turns out, I was wrong. On the bolt dyno a $40 digital adapter performed similarly to a dedicated torque wrench. The former is especially helpful with a torque-to-yield bolt that requires both a torque spec and additional tightening by a certain number of degrees. The adapter used in this test was also good enough that it could be used to calibrate most home-use torque wrenches or, at least, confirm they are still working as expected.
Takeaway: True!
So maybe torque wrenches are a bit misunderstood. Hopefully Torque Test Channel put a few of your minds at ease. It also tests a few more myths than discussed here, so be sure to check out the full video if you want to see more fun torque-wrench testing.
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The big thing with the smooth pull is not overshooting
The double-click is more about making sure you got ’em all then making sure you got the right torque
3 and 5 are learnings for me… I’ve had don’t drop the torque wrench drilled into my head for years. I will probably still store my torque wrenches de-slacked but now I know it doesn’t matter as much as I thought it did
Good article. I use torque wrenches on critical items like head bolts and other engine internals, as well as lug bolts, but I refuse to accept that every nut and bolt on the whole car needs torquing. Some things, like spark plugs with crush washers, always feel funny to me at their prescribed torque readings. And I’m gonna trust my elderly learnedo hands more than simply a torque reading on a plug going into a 45-year-old aluminum cylinder head.
My understanding is you should dial it back to zero to preserve the spring from breaking early and the wrench will live longer. Not sure if true but that was what I did.
I had our guy that calibrates all our stuff tell me to set the torque wrench to it’s lowest setting when storing. So I always do.
Nice to know about those digital adapters, I already have several click type wrenches, but for the cheap price I may add one of those to the roster.
My biggest pet peeve, by FAR is people that push more after the wrench clicks. Why use a torque wrench at all if you’re going to ignore the setting?
Good topic, Kyle. Maybe I missed it somewhere, but I’d be interested in the history of the evolution of the torque wrench itself. I started out with one of those bar/swing scale type Craftsman tools (not sure of the proper terminology, but there is a pointer and a semi-circular scale near the handle). From Day1 it seemed awfully inaccurate – or at least harder to be accurate – to me. When I got my first click-style, I was thrilled. Then I talked to a friend with a digital style who thought he’d reached Torque Nirvana I wasn’t as impressed). I understand there are a couple of other types of this tool out there, which I know little-to-nothing about.
My old 1/2″ drive swing arm Craftsman is relegated to the “old tool wall” and only looked at with nostalgia these days, and the foot-pound and inch-pound clickers have their spots in the tool drawer. I’m on board with TG in having learned a couple of things in this article, so thanks for that!
I believe those are called “beam balance” torque wrenches. I have two of them. One is a Craftsman – probably the same thing you have on your wall.
Just looked it up. They’re called “deflecting beam” torque wrenches.
Sounds about right, thanks! I’m betting yours and mine are indeed the same – Craftsman must’ve sold about a jillion of them back in the day.
I sometimes use the old “beam” style wrench to undo a bolt. If you watch carefully you can see what the torque was just before it loosens. This can help put you in the ballpark if you don’t know the torque required for re-tightening. Can’t do that with the clicker.
Great point. Will try to remember that when the need arises – that wall hanger may just see some new life yet!
Thanks for clarifying torque wrench tech. I bought a Craftsman 1/2″ drive, 150″ ft lb tool for my truck axles. I discovered it would not operate for LEFT hand application on my Harley clutch basket. Rip-off.
Get a rachet adapter.
RTFM in all cases. There was a Snap-on tool in my shop that allowed for the ratchet operation. After it came back from calibration repaired (and woefully out of calibration), I ground off the ratchet knob. The tech was mad at me, but I simply could not allow a tool on the floor that could easily produce faulty results.
I don’t know how crucial a Harley clutch basket is, E.G. what happens if it only gets say 1/3 of the torque specified? I know I sure don’t want wheels falling off a car.
I’ve got that same Craftsman torque wrench with the red locking ring. I love it. Unfortunately mine didn’t come with the fancy blow-molded case!
Interesting! That one came from a Sears store (so I’ve had it a minute or two…) and there was a plastic cover that popped off. The case just seemed too nice to immediately throw away.
I had a good wrench for years but it broke the spring inside. I think it is laying around. I replaced it with the large Sears clicker and the smaller inch pound I used like crazy on my sons soap box derby car.
We torqued the King pin in the axles with the inch pound ratchet. It was one form of tuning the car as the tighter it was the faster it could make the car as long as you keep the weight equal on each wheel with cross bind. There is a real science around those cars.
I was one of few from the outside that learned enough to have been able to set up a car fast enough to win. Most are derby families. We all lived and died often with the torque wrenches.
Good article Kyle, thank you.
Showing my age but my first was a Craftsman ‘beam type’ as I call it although I (like DUB6) am not sure of the correct terminology. I also have the newer lower torque (250 in-lb) click type similar in design to the one shown above and a larger / newer 250 ft-lb click type.
I realized very recently that while the wrenches ratchet in both directions, the torque function is only for RH threaded bolts, at least the small Craftsman clicker that I have – I probably should have known that but didn’t until I sheared the LH M6 fastener I was attempting to tighten to spec (89 in-lb). I ended up using my original ‘beam type’ wrench with the replacement bolt since it’s directionally indifferent and the scale exists for LH and RH threaded bolts. Given it’s a 150 ft-lb wrench, it wasn’t plan A for the small bolt but I wasn’t going to pursue wrench #4 for the extremely rarely used LH threaded and small fastener. Thanks again for the good article.
Smart to know the difference between static and dynamic torque. Static, as applied by torque wrenches, is measured in ft-lb units. Dynamic, as produced by a motor or engine, is quantified by lb-ft units. You are now a certified torque expert.
Don, you should heed the statement that “it is better to remain silent and be thought a fool, than to speak and remove all doubt.” The truth is the opposite of what you posit in your comment.
Good information here. Nice to see that some of the things you here are not really true but also not a big deal i you did do them.
Additional myth: the name is not torque wrench, the true name is dynamometric wrench, and by the way the click ones are the most imprecise with at best 4% clockwise and 6% counter clockwise, the best ones are the dial type, with 2% and selected models 1%.
According to Best Reviews, “The problem with dial wrenches is that they rely on a high level of operator skill. Most have no audible warning, nor do they break or cam-over. You must watch the dial (not always easy), and react accordingly.”
I’ve been using torque wrenches for 50 years and never heard of warming it up first. I’m relieved to hear that I don’t have to.
Wish they would have had something in there about how to check calibration…..
My dad was a Quality Auditor for aerospace company that ended up in Honeywell after a number of mergers. For testing large (1″ and 2″) torque wrenches in the ’60s and ’70s hollow square steel bar was welded to the largest steel column in the building and weights were hung on the handle (horizontal) at the appropriate distance from the center of the head. ie – 100lbs 2 feet out was exactly 200 ftlbs. Crude, but accurate.