Can you have too much torque reversing a bolt out? If you do what happens?

[mikey03]

I honestly got very little use for my m18 high torque but used it for the second time tonight. Changing out the chuck on a m18 drill. Youtube said to put a large hex key in the chuck and hammer it off. I wailed a few dozens times no go. Then more YouTubes said to grind it off and also if you bang too much with the hammer on the hex key can brake the gear box inside the drill.

I dug out my m18 high torque, put a 1/2 impact male hex socket on there and it came off in three seconds. Took another minute to pick my jaw off the floor I wasted an hour on this before grabbing the hi torque.

So got me wondering because tekton sells really small sockets for 1/2 drive, not that I’d want to use the hi torque on a 8mm m5 bolt but it exists and what happens if I did it?

If you use too much torque to tighten a fastener you shear the head off. Does the same thing happen if you use too much torque loosening if it’s jammed then I guess the head shears off?

What about torque and female hex is there a risk of it stripping out if you use too much loosening torque?

Was there ever a time you used a tool way too powerful for a fastener on purpose and had a good result?

 

[MichaelP]

Sure, if the fastener is stuck, you can strip the internal hex, round the key or even break off the bolt head (which is much less probable in this case vs. when you use regular socket on a hex head bolt).

And yes, I had good and bad results using too much torque. But I always try to use either penetrating oil, heat or other methods before applying brute force.

 

[mikedodge]

The same thing happens as over tightening it- if it's really stuck it can break or strip. Notice how that happens more taking stuff apart then putting it together.

 

[zimman]

It breaks
Zim

 

[Sweetcorn]

...snip...

If you use too much torque to tighten a fastener you shear the head off. Does the same thing happen if you use too much torque loosening if it’s jammed then I guess the head shears off?
...snip...

In no way am I trying to be rude, but I am so insanely jealous of your lack of knowledge on what happens in this instance.

 

[ecotec]

In no way am I trying to be rude, but I am so insanely jealous of your lack of knowledge on what happens in this instance.

This.

It hasn’t even been a week since I snapped a bolt.

 

[mikey03]

How do you know when it’s okay to try to blast it with a high torque impact or if you should do something else like a torch first? I’m sure it’s alot of experience but anything you guys can share?

 

[Firebrick43]

How do you know when it’s okay to try to blast it with a high torque impact or if you should do something else like a torch first? I’m sure it’s alot of experience but anything you guys can share?

Generally, and I mean generally, an impact is less likely to break the head off of a bolt taking it off than a wrench or socket. The impacts are quick and is more likely to break free the corrosion seizing a bolt than constant torque.

We had one job that had to be done every few years on a giant ingersol portal milling machine using water based coolant. The 40000 lbs pallet had 144 rollers in the bottom with 288 bolts holding the rollers axles in place. After we lifted it and set it on stands 3 or 4 of us would start at the job on creepers. I was the only one with a cordless impact the first time I did it and I didn’t break off any. The other two using 2’ 1/2 drive ratchets broke nearly half a dozen off

It of my honest opinion that if a bolt breaks as it’s breaking free with an impact it would have done the same with a wrench

The only place an impact can get you into bigger trouble is where the bolt threads are exposed and rusty and start to bind after the bolt breaks free. This also happens with a wrench and is solved the same way by screwing the bolt/nut back in half a turn by both but an impact can do it much faster and therefore some don’t react fast enough

 

[Retired dozer fixer]

I honestly got very little use for my m18 high torque but used it for the second time tonight. Changing out the chuck on a m18 drill. Youtube said to put a large hex key in the chuck and hammer it off. I wailed a few dozens times no go. Then more YouTubes said to grind it off and also if you bang too much with the hammer on the hex key can brake the gear box inside the drill.

I dug out my m18 high torque, put a 1/2 impact male hex socket on there and it came off in three seconds. Took another minute to pick my jaw off the floor I wasted an hour on this before grabbing the hi torque.

So got me wondering because tekton sells really small sockets for 1/2 drive, not that I’d want to use the hi torque on a 8mm m5 bolt but it exists and what happens if I did it?

If you use too much torque to tighten a fastener you shear the head off. Does the same thing happen if you use too much torque loosening if it’s jammed then I guess the head shears off?

What about torque and female hex is there a risk of it stripping out if you use too much loosening torque?

Was there ever a time you used a tool way too powerful for a fastener on purpose and had a good result?

Not a mechanic are you? Too much torque….BANG and your S O L. Get out your drill and have at it

 

[mikey03]

Not a mechanic are you? Too much torque….BANG and your S O L. Get out your drill and have at it

Not a pro mechanic just do small jobs. I’ve sheared off bolt heads before tightening but never loosening. And only sheared them off tightening by hand.

 

[Retired dozer fixer]

Not a pro mechanic just do small jobs. I’ve sheared off bolt heads before tightening but never loosening. And only sheared them off tightening by hand.

Wasn’t meant as sarcasm. I’ve taken more busted bolts out over my career than I care to with a welder or a drill. Believe me it’s going to be a ****** day when it happens

 

[purplezr2]

I think the correct answers is yes there is a thing as too much torque, and the result is you get to spend a bunch more time working on whatever you are working on.

In no way am I trying to be rude, but I am so insanely jealous of your lack of knowledge on what happens in this instance.

Right, so many broken bolts....

Sure, if the fastener is stuck, you can strip the internal hex, round the key or even break off the bolt head (which is much less probable in this case vs. when you use regular socket on a hex head bolt).

And yes, I had good and bad results using too much torque. But I always try to use either penetrating oil, heat or other methods before applying brute force.

I would say breaking off is much more likely then stripping/rounding as standard hex bolt. Internal hex or torx I would agree will likely strip before breaking.

 

[1Bad55Chevy]

This.

It hasn’t even been a week since I snapped a bolt.

You need to move states... Down here in Texas I honestly couldn't tell you the last time I broke a bolt.

 

[Retired dozer fixer]

You need to move states... Down here in Texas I honestly couldn't tell you the last time I broke a bolt.

Lucky you. I’m in northern Indiana. Rust belt capital of the Midwest

 

[mikey03]

You need to move states... Down here in Texas I honestly couldn't tell you the last time I broke a bolt.

lol yea thats why this never came up for me tbh. I have sheared off when tightening too much being a ******* but so far never while removing. But now I see how that could honestly happen so thank you every body

 

[AEAdam]

High “torque” impact guns are nice to have. I remember when the battery guns came out and I warned people then. Not sure who was behind it, maybe Milwaukee, maybe Astro, but there was a torque space race, with GJ members witlessly participating.

There are jobs where really high torque is required. Specific Honda crank pulley nuts among them. But for 99.9% of jobs, these heavy, brutish, guns are liabilities. Absolutely yes you can break stuff with them.

So what happened? Milwaukee made 1000ftlb guns, and people bought them, then 1500ftlb guns and people bought them. Finally they put 1/2” anvils on 3/8” guns and sold them as 400ftlb “mid torque” guns and people bought them happier with guns sized to their work. They should have left well enough alone. There were perfectly serviceable 1/2” guns in the 500-800ftlb range years and years ago. Non-witless GJ members should be buying them for pennies. I have a now antique Bosch 18v gun that produces right around 500ftlbs that has never let me down. Great tool.

But YES. Be careful with your high torque impact guns. I recommend the smaller 3/8 sized “mid torque” guns for most users.

 

[richfinn]

If the fastener and threads are in good condition and not seized or had Loctite applied then your hi torque impact wrench won't get anywhere near its theoretical maximum torque during removal, it will remove the fastener with ease, it's still overkill and the wrong application for that particular tool as it's more cumbersome and heavy than required (which leads to human fatigue and the risk of collateral damage.).

I think the real answer to your question is "Experience", after a fair while of working on vehicles & machines you get a feel for choosing the correct tool/damage limitation/speed.

It's always safer to work your way up to using brute force, until you are experienced enough to know different.

As an example, I will be more careful if a job risks breaking or stripping a smaller fastener in aluminium, If I'm working on bigger stuff or easily replaced fasteners on exhausts etc. I will just go full brute force and then replace any broken hardware. It's a bit different for pro mechanics as generally we are working against the clock and don't have 30 minutes to try to save a specific bolt that costs $2.50, it's way cheaper for the customer to just snap off or cut a bolt sometimes (as long as you don't need to do any drilling/extracting or tapping).

 

[1Bad55Chevy]

You need to move states... Down here in Texas I honestly couldn't tell you the last time I broke a bolt.

I posted this today and literally went outside and broke a bolt, luckily it was on a car i was scrapping. It was a stud holding the converter to the exhaust manifold on a 08 Pontiac G6 3.6.

 

[Beerhippie]

If it breaks, you have too much torque. Rest assured, it would have broken using any other means.

With stuck fasteners, heat and penetrating oil are always your friend. Use multiple cycles before going for the BFH--or BFIG.

 

[Sweetcorn]

I posted this today and literally went outside and broke a bolt, luckily it was on a car i was scrapping. It was a stud holding the converter to the exhaust manifold on a 08 Pontiac G6 3.6.

Haha!

 

[Mr_B]

High amounts of torque always has a potential to break or damage fasteners .
A lot of times when dealing with a fairly stuck bolt you better using lower power setting and letting the vibration of impacts help work it out along with frequent use of penetrating oil and working the fastener backwards & forwards small amounts to clear the threads and help get a bit of penetrating oil in to ease the friction and heat build up .
By starting with a hand ratchet or wrench and getting perhaps 1/4 of a turn then moving to a good nano air impact ( I like air as far more variable and controllable torque output via settings and trigger) you can get a lot of stuck fasteners out without needing go to heat methods .
Very useful method as can be fairly quick/simple and in scenario where can not use heat easily it can save the day .
Approach same scenario with high torque and you either rounded fasteners/broke your socket or snapped the fastener & then got deal with a possible difficult extraction or needing more new parts and getting tools replaced ...

 

[AEAdam]

High amounts of torque always has a potential to break or damage fasteners .
A lot of times when dealing with a fairly stuck bolt you better using lower power setting and letting the vibration of impacts help work it out along with frequent use of penetrating oil and working the fastener backwards & forwards small amounts to clear the threads and help get a bit of penetrating oil in to ease the friction and heat build up .
By starting with a hand ratchet or wrench and getting perhaps 1/4 of a turn then moving to a good nano air impact ( I like air as far more variable and controllable torque output via settings and trigger) you can get a lot of stuck fasteners out without needing go to heat methods .
Very useful method as can be fairly quick/simple and in scenario where can not use heat easily it can save the day .
Approach same scenario with high torque and you either rounded fasteners/broke your socket or snapped the fastener & then got deal with a possible difficult extraction or needing more new parts and getting tools replaced ...

You had me in the beginning then I lost you.

2 issues I deal with:
1) it’s stuck on and I need an impact to get it off. This is caused by corrosion at what I’d call the ”faying” or “fay” surface, where the underside of the head or nut meets the car, as well as corrosion in the threads. This is typically why we use impacts in the first place.

2) For nuts, sometimes the exposed threads can be as problematic or more.

So as @Mr_B said, I pretreat, if possible a day before a nasty job then immediately before with penetrating oil. Then impact. Then finish by hand and go back and forth if I’m unscrewing a nut say, onto really corroded threads (e.g. exhaust).

My high torque impact gun sometimes spins too fast for my liking. With lugs it’s usually ok. But it can spin me into bad threads even on lugs. I sheared a wheel lug on my sons Kia this way a few weeks back. Would have prefered to just crack free with impact, then finish by hand.

Moral of the story: be careful with the high speed guns and maybe not use that as your daily driver. As @richfinn said, good technique really helps. Impacts aren’t tools for dummies.

 

[zimman]

How do you know when it’s okay to try to blast it with a high torque impact or if you should do something else like a torch first? I’m sure it’s alot of experience but anything you guys can share?

Honestly I'd never use an impact on the first throw if it looks sketch. Breaker bar and slow steady pull, no jerking or pumping and both tighten and loosen. Situational awareness is important. If it all looks like ****, slow down
Zim

 

[Paycheck]

I’ve heard a rumor that if you tighten a stuck bolt just a hair first then loosen it tends to help break it free. All done without a power tool of course.

 

[Mr_B]

I’ve heard a rumor that if you tighten a stuck bolt just a hair first then loosen it tends to help break it free. All done without a power tool of course.

Yes can help.
Every time I have a stuck bolt or a bolt that known be potential trouble remove I first try move it 1/8th to a 1/4 turn with ratchet or wrench prior to going to any impact tool, once it shows some movement and get it to 1/4 a turn from tightening/loosening then I switch to air impact on mid power range and good throttle control to keep working it back and forth and keep giving it squirts of penetrating oil until it start moving easier and can back it all way out .
Slightly less power and constant vibrations can help break the corrosion bond, sometimes massaging the bolt head with air hammer can help loosen stuck bolts (works well on balljoint pinch bolts but needs be done with controlled power)
I use to work on lot of military diesel engines and we use to remove glow plugs using impact with power turned down & keep it rattling on the glow plug for good 5 minutes or more at a time and perhaps up power a little when really stubborn but patience with little less power could get good results and save lot of time over extracting broken off glow plugs .
I use the technique daily in automotive repair and saves me lot of time and hassle ...

 

[AEAdam]

Honestly I'd never use an impact on the first throw if it looks sketch. Breaker bar and slow steady pull, no jerking or pumping and both tighten and loosen. Situational awareness is important. If it all looks like ****, slow down
Zim

I think this is backwards. I think the sustained load from a breaker is more likely to shear a fastener. The advantage of the impact gun is that it applies a tremendous force, which becomes a tremendous torque, but for a very short time. If you applied even a fraction of the torque an impact gun can apply, you’d shear the fastener.

Ideally, @mikey03 assumption is correct. Impact is the right tool, but you kinda want it sized to the need. My guess is this is why air impacts had switchable power knobs. Sometimes you don’t want max torque.

 

[Nutria]

Yes. For me, penetrating oil, then impact with low torque tapping to get things moving (and to get the oil in deeper).

 

[niget2002]

How do you know when it’s okay to try to blast it with a high torque impact or if you should do something else like a torch first? I’m sure it’s alot of experience but anything you guys can share?

I always work my way up to it.

socket
wrench
cheater
impact
torch

 

[Ohio Andy]

Not a pro mechanic just do small jobs. I’ve sheared off bolt heads before tightening but never loosening. And only sheared them off tightening by hand.

Plumbing... Lots of smaller screws close to water... Then they rust in place.

Not two distant past. I was working on one under a sink. Now that one I was hoping it would break cuz it was a bolt with a nut and if it broke it should have just come right out... I went through a a couple pairs of vice grips before I pulled out my special ones... I felt like a contortionist fixing that

 

[308guru]

How do you know when it’s okay to try to blast it with a high torque impact or if you should do something else like a torch first? I’m sure it’s alot of experience but anything you guys can share?

When the impact doesn't remove the fastener you get the torch out.

 

[AEAdam]

When the impact doesn't remove the fastener you get the torch out.

I’ve skipped this step. There’s so much plastic on cars now, I feel this is advice from the 1980s. Very rare I think I could safely put a torch to a fastener on a modern car. My bobcat has a bolted on edge on its bucket. Would totally use a torch for that.

For me if it just looks tight, I go with my smaller impact first. If the big impact doesn’t work, I typically get out a drill or a sawzall.

 

[zimman]

I think this is backwards. I think the sustained load from a breaker is more likely to shear a fastener. The advantage of the impact gun is that it applies a tremendous force, which becomes a tremendous torque, but for a very short time. If you applied even a fraction of the torque an impact gun can apply, you’d shear the fastener.

Ideally, @mikey03 assumption is correct. Impact is the right tool, but you kinda want it sized to the need. My guess is this is why air impacts had switchable power knobs. Sometimes you don’t want max torque.

I'm not a metallurgist but my mentor in auto mechanics told me to go after it like this. He had a few drawers of air tools and always brought a ratchet or breaker to the problem children. Us. LMAO
Zim

 

[Wamsutta]

Changing out the chuck on a m18 drill.

There's usually a little screw down in the middle of the chuck. You gotta remove that first before spinning the chuck off.

Could be left hand threads so you gotta watch out for that too.

 

[mikey03]

There's usually a little screw down in the middle of the chuck. You gotta remove that first before spinning the chuck off.

Could be left hand threads so you gotta watch out for that too.

I took the screw out and was turning the right way with the hex key trick but it was on there too tight. The hi torque took it off instantly. I guess Milwaukee gets them on real tight tbh because there’s tons of videos on YouTube of people grinding them off when the hex key and hammer fails.

I tried the mid torque first at 600 ft pounds and failed. Then hi torque and boom off

 

[Sumboodie]

Wasn’t meant as sarcasm. I’ve taken more busted bolts out over my career than I care to with a welder or a drill. Believe me it’s going to be a ****** day when it happens

I had one that I guess the force of it snapping off broke the rust loose. I easily tapped it out with a punch.

I took the screw out and was turning the right way with the hex key trick but it was on there too tight. The hi torque took it off instantly. I guess Milwaukee gets them on real tight tbh because there’s tons of videos on YouTube of people grinding them off when the hex key and hammer fails.

I tried the mid torque first at 600 ft pounds and failed. Then hi torque and boom off

I have the 3/8 M12 that's allegedly 500 ft lbs busting nuts power ir something like that.
I've had plenty of bolts it couldn't do the M18 1/2" did, and if that can't, often my IR2135 at ~150 psi does.
After that, bust out the torch and ir 3/4 or 1" air guns. Or 18:1 torque multiplier

 

[djbmw]

I honestly got very little use for my m18 high torque but used it for the second time tonight. Changing out the chuck on a m18 drill. Youtube said to put a large hex key in the chuck and hammer it off. I wailed a few dozens times no go. Then more YouTubes said to grind it off and also if you bang too much with the hammer on the hex key can brake the gear box inside the drill.

I dug out my m18 high torque, put a 1/2 impact male hex socket on there and it came off in three seconds. Took another minute to pick my jaw off the floor I wasted an hour on this before grabbing the hi torque.

So got me wondering because tekton sells really small sockets for 1/2 drive, not that I’d want to use the hi torque on a 8mm m5 bolt but it exists and what happens if I did it?

If you use too much torque to tighten a fastener you shear the head off. Does the same thing happen if you use too much torque loosening if it’s jammed then I guess the head shears off?

What about torque and female hex is there a risk of it stripping out if you use too much loosening torque?

Was there ever a time you used a tool way too powerful for a fastener on purpose and had a good result?

Yes. In fact, most of the broken fasteners have been caused by an attempt at removing them, not installing them. Having said that, an impact gun is a much safer way of delivering torque to a fastener as opposed to a constant torque via a breaker bar (much more likely to shear a bolt).

As for your question about over torquing on installation... that can stretch threads, fatigue metal, strip out threads, snap the bolt.. etc.

 

[cparke]

The type of metal really matters as far as what to do. Cracking it loose is the hardest part.

I tried removing a stuck bleeder valve on the car's wheel caliper and the head broke off. Luckily the way these are designed, they won't release brake fluid even with the head missing. Either need to change the caliper or use a bolt remover tool (reverse threaded drill bit) now to get it out.

I also get really nervous with one-time aluminum bolts used on engine blocks. When tightening, you're supposed to first tighten to a torque value and then add a 1/4 turn or something like that. Do it wrong and the head will break off. Also want to be careful when starting to remove, again to avoid the head breaking off in the process.

Never had much luck with penetrative oils, maybe I'm impatient or doing wrong. Not sure how that is supposed to get down the threads. Blowtorch for heating I don't have and never tried, sounds dangerous.