Do torque sticks wear out?

[chris142]

I have a 65 ft lb torque stick I use on lug nuts. I have used it often for the past 10 years or so. After it I use a tq wrench to finish tightening the lugs. Most are 90-120 or so ft lbs.

Today I used it to snug up some lugs. I then got my tq wrench,set it @114 ft lbs and found the lugs to already be very tight . Much tighter than the 65 ft lbs the stick is rated for.

I had to use a breaker bar to loosen the lugs so that I could properly torque them.

Can a torque stick fail in a way that allows it to put out more tq than it's rated for?

 

[Hobby_Man22]

Sure. Everything wears out eventually. You might be putting too much torque on it though. 65 ft lbs isn't much

 

[pattenp]

Are you using an electric impact or air impact? I find using an electric impact with torque sticks over torque compared to using air impact.

 

[chris142]

Are you using an electric impact or air impact? I find using an electric impact with torque sticks over torque compared to using air impact.

I'm using my 35+ yr old I.R. 231a air impact.its never been opened up.

 

[rlitman]

...Can a torque stick fail in a way that allows it to put out more tq than it's rated for?

I don't see how. Torque sticks are just torsion springs. They twist when the impact reaches a certain torque, but how much torque the spring absorbs without passing through depends on many factors. There's a reason the instructions are vague.

As for failing, I don't think an impact gun has the power to deform a torque stick to yield, and if it did, I believe that would make it put out less torque than expected, not more.

For my purposes, I've never needed more than the smallest stick in the set. The rest of the set was a total waste. I always just use the stick to impact on just enough that there's still room for the torque wrench to finish the job, and at that point, getting an accurate torque value isn't all that important to me.

 

[bwringer]

Another possibility might be that the drive or socket end are deforming and the increased space is letting the gun hit harder?

Or perhaps you're left with looking at your torque wrench. Of course, by now your elbow should know pretty well what to expect.

Or perhaps try a different impact gun. Again, your ear knows what to expect, so if your impact gun is behaving differently, you should have noticed something.

As noted above, battery impacts can over-torque; I'm not sure why, and I don't know if anyone really quite understands, but the best guess is that the faster impacts don't let the torsion bar relax between strikes.

 

[seber]

It seems unlikely in this setting but enough shock on tool steel can harden it beyond the initial heat treat setting. If that happened you would see increased torque.

 

[2ndGearRubber]

I have a 65 ft lb torque stick I use on lug nuts. I have used it often for the past 10 years or so. After it I use a tq wrench to finish tightening the lugs. Most are 90-120 or so ft lbs.

Today I used it to snug up some lugs. I then got my tq wrench,set it @114 ft lbs and found the lugs to already be very tight . Much tighter than the 65 ft lbs the stick is rated for.

I had to use a breaker bar to loosen the lugs so that I could properly torque them.

Can a torque stick fail in a way that allows it to put out more tq than it's rated for?

That's the reality of torque sticks. They don't limit nearly the way people expect them to. Small variations can lead to overtorque even with a torque stick. An 80ftlb can easily apply 120+. Using an electric impact it gets even crazier. Check your torque wrench for sanity, but the typical function of a torque stick really needs to be just snugging the lugs and not letting the gun hammer at all. The stick should not "wear" to the point it acts radically different unless it's severely bent or similarly damaged, in which all guesses are valid to the performance.

Odds are you just let it whack a little longer than normal.

 

[dnschmidt]

FACT: Electric impacts hammer so fast that the torque stick does not have time to relax between hits so they are prone to over torque

SUPOSITION AND OPINION: It's hard for me to believe that the metallurgy of a torque stick can change. Using a tried and true I-R 231 should be fine as its impacting speed is much slower than the cordless models. The rating of a torque stick is directly related to its diameter. I use the Accu-Torque sticks that are one piece and not extensions. Can't see how the diameter of the stick can change. So I have no explanation for this.

 

[chris142]

That's the reality of torque sticks. They don't limit nearly the way people expect them to. Small variations can lead to overtorque even with a torque stick. An 80ftlb can easily apply 120+. Using an electric impact it gets even crazier. Check your torque wrench for sanity, but the typical function of a torque stick really needs to be just snugging the lugs and not letting the gun hammer at all. The stick should not "wear" to the point it acts radically different unless it's severely bent or similarly damaged, in which all guesses are valid to the performance.

Odds are you just let it whack a little longer than normal.

We actually did check our torque wrenches by putting 2 together and they both clicked at nearly the same time. The lugs were way too tight. I know how 115 ft lbs feels by hand and they were very tight

 

[yellowbox]

I have broken them before, a strong gun will do it

 

[mikey03]

Sure. Everything wears out eventually. You might be putting too much torque on it though. 65 ft lbs isn't much

lol read thread title and my first thought before clicking is everything wears out

 

[WildBill]

Based on the fact that my local Les Schwabby uses them and the lug nuts are at approximately 2000 ft pounds afterwards I don't think they work like people think they do. Luckily I don't know until six months later when I try to take the tires off and end up breaking some studs trying to get the friction welded nuts off.

 

[Schurkey]

Fling the torque sticks into the scrap metal bin. They never were an acceptable procedure, the whole point of them is to be a short-cut for people unwilling to do it right. The whole premise of using a torsion bar connected to a random input power and expecting a consistent result is a guess based on a hunch, resulting in an uncertainty.

Use the torque wrench to achieve proper tension. (The curmudgeons among us will soon chime-in and say the torque wrench is uncertain enough.)

 

[richfinn]

I think there are too many variables nowadays for even the original Accutorq sticks to be a viable proposition.

Back in the 90s before Cordless Impacts became a thing we used them in our dealership where all the wheel bolts were 110 nm and a lot of regular cars were still on steel rims (so the tool was a one piece with the socket integrated made out of high quality Swedish steel). We also knew the pressure was regulated correctly and the guns were maybe 25-30% less powerful than the latest air impacts.

Now you are adding a detachable non marring socket and dealing with more complex lug nuts (with conical washers and chrome outer skins) onto sticks made God knows where out of who knows what.

I like to use the "snug setting" on my Milwaukee M18 mid torque (which I think is approximately 35 nm) then finish with a clicker torque wrench to spec.

 

[Rusted Nut]

I got new tires put on at a Goodyear truck tire shop a few months ago. The tire guy was an older dude, using torque sticks. I asked him if those things were accurate. He said they check/calibrate them monthly, but they’re toast after about two years.

 

[rlitman]

I got new tires put on at a Goodyear truck tire shop a few months ago. The tire guy was an older dude, using torque sticks. I asked him if those things were accurate. He said they check/calibrate them monthly, but they’re toast after about two years.

Two years in a tire shop is plenty of time to wear out several sizes of impact sockets (and maybe even an impact's anvil). As for a torque stick, the question of fatigue life isn't that simple to answer, because it depends so much on the amount of abuse it sees. Keep it under the limit, and the fatigue life of steel is longer than it'll take for that tool to rust away in a clean toolbox drawer (i.e. easily the length of human history).

 

[Junkdrawer Dog]

Based on the fact that my local Les Schwabby uses them and the lug nuts are at approximately 2000 ft pounds afterwards I don't think they work like people think they do. Luckily I don't know until six months later when I try to take the tires off and end up breaking some studs trying to get the friction welded nuts off.

This seems to be a generic problem with a lot of tire shops. The only place that never did me this way was The Tire Rack in South Bend Indiana. With the others, I've been known to take the wheels in loose and return home to install them myself.

 

[Hohn]

Can a torque stick fail in a way that allows it to put out more tq than it's rated for?

Not really. Torque sticks work because they have some amount of torsional stiffness that's calibrated. The idea being that they deflect enough to absorb impacts once some reaction torque is achieved.

But in order for them to work, they have to fall within the range of a couple assumptions. One is the total impact energy. If the size of the blow is sufficiently large, then the torque stick will permanently deform or break if it doesn't just allow massively too much torque.

Another assumption is the BPM of the impact. If you are using a tool with a very high BPM, then it can apply blows faster than the torque stick will unwind from the previous blow. This will cause the applied torque to exceed the rating of the torque stick as the blows "pile up" faster than the stick can absorb them.

It far more likely that you are simply using a drive tool not compatible with those torque sticks. Unfortunately, the makers of the sticks do not publish info about what does or doesn't work with them in terms of max BPM or torque...

 

[908Jim]

Not really. Torque sticks work because they have some amount or torsional stiffness that's calibrated. The idea being that they deflect enough to absorb impacts once some reaction torque is achieved.

But in order for them to work, they have to fall within the range of a couple assumptions. One is the total impact energy. If the size of the blow is sufficiently large, then the torque stick will permanently deform or break if it doesn't just allow massively too much torque.

Another assumption is the BPM of the impact. If you are using a tool with a very high BPM, then it can apply blows faster than the torque stick will unwind from the previous blow. This will cause the applied torque to exceed the rating of the torque stick as the blows "pile up" faster than the stick can absorb them.

It far more likely that you are simply using a drive tool not compatible with those torque sticks. Unfortunately, the makers of the sticks do not publish info about what does or doesn't work with them in terms of max BPM or torque...

Came here to say this^

Torque sticks are not torque limiting devices. They are useful if you know how they will behave on your impact through enough trial and error. My 90ftlb torque sticks was over shooting unless I dialed the gun back, which I found to be annoying. I now use a 75 ft lb, which overshoots by 10-15 ft lbs, then finish with a torque wrench.

I must have over torqued hundreds of lug nuts before realizing this, thanks to GJ some 10 years ago.

 

[Kurt4440]

I use an old impact driver with a 1/2" adapter and run it with a 2 ah battery. This setup snugs up the lug nuts or bolts perfectly, and then I follow up with the torque wrench. An extra set of lug nut sockets speeds up the process as well.

 

[Schurkey]

My 90ftlb torque sticks was over shooting unless I dialed the gun back, which I found to be annoying. I now use a 75 ft lb, which overshoots by 10-15 ft lbs, then finish with a torque wrench.

I must have over torqued hundreds of lug nuts before realizing this, thanks to GJ some 10 years ago.

Where's the logic in using the torque stick at all? Zip the nuts snug with the impact wrench, torque 'em with the torque wrench.

Adding in a step where the torque stick is used is just a waste of time and effort--ESPECIALLY if you have to "cheat" on the torque sticks because they're inherently inaccurate and unreliable.

 

[2ndGearRubber]

Where's the logic in using the torque stick at all? Zip the nuts snug with the impact wrench, torque 'em with the torque wrench.

Adding in a step where the torque stick is used is just a waste of time and effort--ESPECIALLY if you have to "cheat" on the torque sticks because they're inherently inaccurate and unreliable.

Point being, they lower torque. So if one is using a powerful gun it makes it easier to throttle back the power. Same idea as slapping a 12" impact extension on there, but even more so. The goal of a torque stick is to set up the install torque below the final torque with minimal effort/consistency. Yes you can turn down the air pressure, switch to a weaker gun, or adjust the impacts output selector. The whole selling point of torque sticks is to ignore all that, slap it on, and get a "reasonable" output.

What has been my experience is that the torque sticks still wildly overshoot. However, I'd rather a careless lubetech use a torque stick than just go wide open with a strong impact. The torque stick will limit some of the force no matter what, it's just not guaranteed to "meet" the stamped number on the side of the stick.


Most shops use a torque stick to keep the output of the guns out of the realm of insanity. The torque stick still over torques, and then they want the techs to go around a click the wrench. Doesn't make a difference as the wrench just clicks as the lugs are already over torqued, but that's a common policy.

 

[Schurkey]

A "Lube Tech" or "Tire Guy" ought to be sharp enough to recognize reverse-thread lug nuts, start lug nuts by hand, (no cross-threading) zip 'em snug but not "tight" with the impact--air, corded-electric, or cordless--and then apply proper torque using a standard torque wrench.

I can't understand the need to dial-down an impact wrench, including use of a torsion-bar when they've all got triggers that don't need to be held-down until the socket stops turning.

 

[2ndGearRubber]

A "Lube Tech" or "Tire Guy" ought to be sharp enough to recognize reverse-thread lug nuts, start lug nuts by hand, (no cross-threading) zip 'em snug but not "tight" with the impact--air, corded-electric, or cordless--and then apply proper torque using a standard torque wrench.

I can't understand the need to dial-down an impact wrench, including use of a torsion-bar when they've all got triggers that don't need to be held-down until the socket stops turning.

A quick tap of the impact hammers, as fast as you can react to the trigger, can easily overtorque. I'd argue unless you're just spinning the lug nuts down at 10rpm, many modern impacts are incapable of applying say 80 ft/lb. They're just too powerful if they get even a 1/4 second of hammer application. I run the lug nuts down and blip the throttle on my astro stubby as fast as I physically can to limit the torque, it can still blow past 80 ft/lb in that instance of hammer application.

That's why people use them, like it or not, that's the theory. I don't use torque sticks so it really doesn't matter to me.

 

[Sumboodie]

When I worked at Sears in the 2000s, breaking torque sticks wasn't uncommon. They'd fatigue from the thousands of uses on guns running on probably 150+psi.

 

[Hohn]

When I worked at Sears in the 2000s, breaking torque sticks wasn't uncommon. They'd fatigue from the thousands of uses on guns running on probably 150+psi.

If that's occurring, then the sticks are indeed being overloaded and plastically deforming. A fatigue cycle can only occur when material yields (microscopically, but still).

 

[rlitman]

Where's the logic in using the torque stick at all? Zip the nuts snug with the impact wrench, torque 'em with the torque wrench.

Adding in a step where the torque stick is used is just a waste of time and effort--ESPECIALLY if you have to "cheat" on the torque sticks because they're inherently inaccurate and unreliable.

Because that magic zone between "snug" and over-torqued is for the most part unattainable. That's EXACTLY where a torque stick helps.

 

[Hohn]

If you guys cannot modulate the trigger on your impact, you need to turn down the pressure and/or get an impact with a better trigger.

 

[2ndGearRubber]

If that's occurring, then the sticks are indeed being overloaded and plastically deforming. A fatigue cycle can only occur when material yields (microscopically, but still).

Usually the failures are at the ends. Detent balls/rings failing, female drive ends wallowing out or cracking.

If you guys cannot modulate the trigger on your impact, you need to turn down the pressure and/or get an impact with a better trigger.

Nobody can brap an impact and hit 70ft/lb repeatedly by feel. You may think you can but check it with a torque wrench. +/- 10 ftlb is about the best I've ever produced reliably at the low torque levels using a full size gun. IR, astro, snap on, it's just not that simple when 1/4 second or less difference in trigger hold wildly changes output.


Now if you're using something inherently weak sauce, that's a different story. If the gun can't install at more than 100ftlb all of a sudden throttling to 80 is achievable. But an IR 2235 which can snap M14 studs isn't going to be super repeatable in applied torque if the hammers hit for even an instant. Running it down to 20ftlb and then torquing up like how you're supposed to, it can do that.

The whole premise is consistency. The torque stick is get keep the output in the ballpark. Then the user can adjust as required to get the output. I can put 150ft/lb through a 80lb torque stick with an Astro Thor and ~1 second of hammer.

 

[AEAdam]

Not really. Torque sticks work because they have some amount or torsional stiffness that's calibrated. The idea being that they deflect enough to absorb impacts once some reaction torque is achieved.

But in order for them to work, they have to fall within the range of a couple assumptions. One is the total impact energy. If the size of the blow is sufficiently large, then the torque stick will permanently deform or break if it doesn't just allow massively too much torque.

Another assumption is the BPM of the impact. If you are using a tool with a very high BPM, then it can apply blows faster than the torque stick will unwind from the previous blow. This will cause the applied torque to exceed the rating of the torque stick as the blows "pile up" faster than the stick can absorb them.

It far more likely that you are simply using a drive tool not compatible with those torque sticks. Unfortunately, the makers of the sticks do not publish info about what does or doesn't work with them in terms of max BPM or torque...

Why don't you think that, used improperly, they could work harden, which would result in higher torqued hardware?

I think the quick answer has to be YES.

 

[Hohn]

Why don't you think that, used improperly, they could work harden, which would result in higher torqued hardware?

I think the quick answer has to be YES.

All steel has the same elastic modulus of 200GPa, regardless of hardness. So even if it hardens, it won't get stiffer and the torsional modal resonances won't chance.
The more likely effect of work hardening it that it will fatigue crack faster from the loss of ductility. And of course, work hardening also requires plastic deformation. So it ends up moot whether you have a work-hardenable grade or steel or not-- if it plastically deforms repeatedly, it will fatigue crack.

Same destination, slightly different routes.

 

[Hohn]

Torque sticks are not torque limiting devices.

This is an important point. A torque stick cannot limit torque per se. Slap one on a torque wrench and you'll be able to apply any torque you wish up to and far beyond the "rating" of the torque stick until it shatters or twists into a pretzel.

No, a torque stick is essentially a form of damping; it is an *energy* absorbing device. Now it just to happens that under some conditions, a certain energy of rotational blow will result in a certain amount of torque being applied.

You could develop a controlled process that makes torque sticks viable, but it would require in impact with relatively low BPM (i.e an air gun, batteries need not apply as they have very BPM) *and* it would need several other parameters controlled.

For example, you could develop a process that says that this particular air impact on this particular hose with this particular regulated air pressure will, when activated for a precisely controlled number of blows, will results in a repeatable torque value of "x".


It's no different than saying that if you snugged a bolt to 20lb-ft, then dropped a calibrated weight from a calibrated height onto a reference wrench (always the same) such that it impacted the same point on a horizontally-oriented wrench every time, it would have a consistent a repeatable relationship of the number of blows to the residual torque of the bolt.

And there would eventually be some level of torque at which that same weight from that same height hitting the same wrench at the same position in the same orientation (whew!) would no longer be capable of further tightening the bolt.

Torque sticks CAN work.
But nobody ever invests in the work required to verify them and develop a process that makes them repeatable. Absent that investment, they are best used as an "overtorque prevention snugger" that snugs before final torqueing via actual torque wrench.

 

[Schurkey]

When I worked at Sears in the 2000s, breaking torque sticks wasn't uncommon. They'd fatigue from the thousands of uses on guns running on probably 150+psi.

I don't have words for the management failure--the self-defeating sillyness--of this.

Because that magic zone between "snug" and over-torqued is for the most part unattainable.

Entirely untrue. How hard can it be to achieve anywhere between 10 and 85 ft/lbs if your ultimate torque target is 100 ft/lbs?

If you guys cannot modulate the trigger on your impact, you need to turn down the pressure and/or get an impact with a better trigger.

Exactly what I've been trying to say, but spoken more elegantly that I did. God bless you.

I have ZERO problems getting "snug" but not over-tightened using any of my various air-impact wrenches including but not limited to full-size 1/2" drive CP734, (company-supplied, decades-ago) Blue-Point AT500B, (sold) Snappy IM510B, (sold) and currently-owned IM6100 "beater", and MG725 "tough-job" wrenches. I run my regulator at ~135 psi, but I have a hundred feet of air hose so there's right around 90 psi at the air inlet of the tool, with the tool running.

But in this day and age, who is using a half-inch gun for lug-nut work? Mostly I'm using a Snappy "1/2-inch, extended anvil in a 3/8-inch impact wrench body" MG3255L. The extended anvil works with lug-nut "flip sockets".

Snap-on Store

shop.snapon.com

 

[Hohn]

I don't think 1/2" for lugs on passenger cars is at all unrealistic. If anything, with more powerful modern guns you need the 1/2" drive (at least) to keep from destroying the square drive recess on 3/8" sockets. Not to mention, 3/8 drive impact sockets in common 22mm and such sizes aren't super common. Not everyone is using premium sockets that can hold up with the smaller drive. If I'm incurring the cost of replacing sockets, I'm using 1/2" drive for the drive durability.

Agree that you don't need the larger gun for its torque. But there are reasons to choose 1/2" that don't have much to do with wanting or needing a more powerful gun.

Especially now that so many lightweight-yet-sufficiently-powerful 1/2" guns are out there. I saw a video of one tire tech extolling the virtues of the Aircat 1375XL as his preferred gun because it's only 3#, it's quiet and feels great in hand, but has plenty of power for most uses.

I think the Snappy MG3255L is probably the ideal tire shop gun because it has the extended anvil and light weight. While you MIGHT need a gun periodically with more power, you will appreciate the light weight every time you touch it, especially the 99% of the time when it's got plenty of power.

 

[rlitman]

...Entirely untrue. How hard can it be to achieve anywhere between 10 and 85 ft/lbs if your ultimate torque target is 100 ft/lbs?...

Well we'll have to agree to disagree. Can you throw an egg at a wall and get it to split without breaking the yolk? Can you do it 20 times in a row? How about blindfolded, not knowing how far the wall is or what it's made of? If my impact is turning so slowly that that Goldilocks zone can be reliably reached with any degree of trigger magic, my impact is too slow to be worth using.

There's way too much of a roulette factor in here. The impact anvil / socket / nut combination needs to be spinning pretty quickly to be faster than a lug wrench, but how much it slows down depends on how close the rim is to being seated on the hub in that sector leading to the cone seat dragging as the rim is driven (an unknowable factor, at least for the first two nuts), and how much rust and dust are on that particular set of threads contributing to the dynamic friction (unknowable in all cases). In the right conditions with clean threads, a seated rim, and room for the spinning parts to accelerate, it's completely possible for the VERY FIRST contact of the impact's hammer to drive the lug beyond spec on inertia alone that's beyond any trigger control factor.

In more reasonable conditions, you need to rely on human reaction time to limit the response, and even there, it's just not reasonable to expect repeatability. If it were, we wouldn't own torque wrenches.

 

[2ndGearRubber]

I don't have words for the management failure--the self-defeating sillyness--of this.


Entirely untrue. How hard can it be to achieve anywhere between 10 and 85 ft/lbs if your ultimate torque target is 100 ft/lbs?


Exactly what I've been trying to say, but spoken more elegantly that I did. God bless you.

I have ZERO problems getting "snug" but not over-tightened using any of my various air-impact wrenches including but not limited to full-size 1/2" drive CP734, (company-supplied, decades-ago) Blue-Point AT500B, (sold) Snappy IM510B, (sold) and currently-owned IM6100 "beater", and MG725 "tough-job" wrenches. I run my regulator at ~135 psi, but I have a hundred feet of air hose so there's right around 90 psi at the air inlet of the tool, with the tool running.

But in this day and age, who is using a half-inch gun for lug-nut work? Mostly I'm using a Snappy "1/2-inch, extended anvil in a 3/8-inch impact wrench body" MG3255L. The extended anvil works with lug-nut "flip sockets".

Snap-on Store

shop.snapon.com

That toy is not doing lug nuts in a shop, even an M18 midtorque fails regularly. Plus even if they do work, each lug nuts is 3-5 seconds of hammering which destroys your ears and wastes everyone's time.

150psi, static, isn't outside the realm of normalcy. You need the increase in static pressure to overcome several hundred feet of line and a hose reel.

 

[2ndGearRubber]

Well we'll have to agree to disagree. Can you throw an egg at a wall and get it to split without breaking the yolk? Can you do it 20 times in a row? How about blindfolded, not knowing how far the wall is or what it's made of? If my impact is turning so slowly that that Goldilocks zone can be reliably reached with any degree of trigger magic, my impact is too slow to be worth using.

There's way too much of a roulette factor in here. The impact anvil / socket / nut combination needs to be spinning pretty quickly to be faster than a lug wrench, but how much it slows down depends on how close the rim is to being seated on the hub in that sector leading to the cone seat dragging as the rim is driven (an unknowable factor, at least for the first two nuts), and how much rust and dust are on that particular set of threads contributing to the dynamic friction (unknowable in all cases). In the right conditions with clean threads, a seated rim, and room for the spinning parts to accelerate, it's completely possible for the VERY FIRST contact of the impact's hammer to drive the lug beyond spec on inertia alone that's beyond any trigger control factor.

In more reasonable conditions, you need to rely on human reaction time to limit the response, and even there, it's just not reasonable to expect repeatability. If it were, we wouldn't own torque wrenches.

I think their point is they want to just roll the lug nuts on to 10ftlb, then torque up. Which most people can do. The difference is if the hammers apply at all. I test my tools, with different sockets, extensions, and thread sizes, so I know how wild the variation can be.

Here in the rust belt, you normally get a puff of aluminum dust as the lug nuts hits the wheel. I'm sure the bolt tension is super accurate.

 

[Sumboodie]

I don't have words for the management failure--the self-defeating sillyness--of this.

No idea what craziness you're talking about since 150psi is normal shop pressure.

 

[MovingAlong]

Lived a lot of years without a torque wrench, swapped a few spares and rotated a few tires too. Knew a lot of farmers growing up, never saw or heard of a torque wrench being used anywhere on anything.

Growing up poor - tight was tight...

I own three torque wrenches now and use them regularly, they're handy and I like them. But I'm also pretty comfortable with the idea that I could get a wheel to stay attached without one. Wouldn't even worry about warping the rotor either..