How to remove rounded Allen head bolts | remove rounded hex key bolts 8 different ways

In this video I’m going to demonstrate
some ways of removing rounded allen head bolts. There are lots of variables
when doing jobs like this but I’ll cover the techniques that I use regularly as
they might prove useful. There are quite a few different types of bolts that use
an allen key or a hex key to undo them. That is a counter sunk one, you then get
button head, and then a popular one is the cap head. or the socket head. There
are some basic things that you need to do before you even attempt to remove a
bolt using an allen key. The first thing we need to do is clean out the head
because there is a chance that there is some dirt in there so it’s good idea to get
something like a small screwdriver and just clean out the head before you even
attempt to remove it using the allen key. This is a massive problem with some
countersunk bolts that we use at work because they are in the floor and the
dirt actually gets compacted in there so you do have to ensure you give them a really
good clean-out before you even attempt to undo them. You always need to ensure
that you use a good quality allen key. This is a very cheap one, you often get these in packs with furniture and to be honest they are not much good for
anything other than assembling furniture. So these really are like a disposable
type of allen key I would not use them for anything serious. An important thing
is to get the correct type of allen key. That is a metric bolt and that is a
metric allen key and you’ll see that that fits in there perfectly. If you
remove that and you try using an imperial allen key that is the closest
size to a 5 mm and you can see that that is very loose. If you try to undo a
bolt using that you will round it off for sure. So you need to ensure that
you get the correct type of allen key. If you have Hex Plus bits like this
there are definitely worth using because there is much less chance of rounding the
head off the bolt. For most of the techniques in this video you are going
to need a decent pair of safety glasses. One thing that works very well is to
shock the bolt you’d be surprised how many tight bolts can be loosened
simply by shocking them using a punch and a hammer. Once you’ve shocked it
there’s every chance that that will loosen the bolt. Another thing you can do
is apply some heat to it or if possible apply some heat to the surrounding area.
Obviously this is not always possible but if it is this can really loosen the
bond. You never actually know if that has been thread locked in if it has it will
make it very difficult to remove it. If you apply some heat to that there’s
every chance that it will loosen the thread locker. Obviously you have to be
careful when you do this you do not want to be breathing in any of the fumes. If
you’re using burning gear and you get that red-hot it is important to let it
cool down before you try to undo it or there’s a chance that you will shear it
off. See that now that’s had a bit of heat on it that is very easy to remove.
You can also try some spray penetrant if you spray that on there’s
a good chance that will loosen the bond between the bolt and the
surrounding material. Some bolts are easier than others to remove for example socket head bolts like these are normally very easy to remove
unless of course they are counter board I will cover that later on in the video.
But if you ever get one of these thats rounded off it’s usually pretty easy to
get out if you put the allen key in there, then take a decent pair of mole grips, I’ve put the allen key in and that will prevent the hole from being crushed
because what happens is when you tighten these up it tends to crush the head. So we
need to get the mole grips on there nice and tight once we’ve done that we can
then undo the bolt. You do have to be careful with some of
these because you may think that they are loose and there’s every chance that you can actually snap the bolt. So with small diameter bolts like that, it’s a good
idea to loosen it off, once it’s loose just back it off a bit and just
ensure that it is completely loose before you go any further. If you move it
slightly and it tightens up spray it with some spray penetrant move it back a
bit and just keep moving it backwards and forwards until it is completely free.
You can remove counter sunk bolts by chasing them out using the cold chisel
and a hammer. It’s critical that you wear safety glasses when doing this. To
do this you just need to hold the chisel at an angle and then give it a good
smack ensuring that the chisel bites into the bolt. You also need to ensure
that you knock it round in an anti-clockwise direction to loosen it. Obviously once you have chased that round a couple of times you can then get the pair of mole grips on that, and we can simply remove the rest of it using the mole grips. By far the easiest method is to weld on a
nut. When you do this you do need to use a nut that is plain you do not want to
use a galvanized nut or a nut that has been zinc plated. Another option that
you can use in some circumstances is to use a left-handed drill bit. These
actually work in reverse and there is a chance that that will bite in there
and actually extract the screw as it bites. So I’m going to put that in the
drill I’m going to ensure that we’re in reverse so we are drilling
backwards and then I’m going to proceed to drill this bolt. There is every
chance that once it starts to bite it actually extracts the screw. Sometimes
this works sometimes it doesn’t. In this example the socket set bolt is
counterbored and the head is stripped. I’m going to drill the head off from the
bolt. It has been shocked and you can clearly see that the head is rounded you
need to get a drill bit that is as close as possible to the same size as the bolt
head. I’m now drilling it off, this bolt is stainless steel and so it is important
not to let it work harden. I’m now using some drilling fluid to keep the bit cool. Once the head is removed we can lift the
cap up to expose the bolt. You will need a decent pair of mole grips
or vise grip pliers. I’m getting the grips as tight as possible on the bolt
and I’m moving the bolt in both directions. The threads in this assembly
are obviously damaged so you do not want to apply too much force or the bolt will
shear which is why I’m moving it in both directions until it becomes free. Once it’s free we can remove the bolt
obviously the hole will be re tapped before it is used again. You can also try
to use a screw extractor these are useful in some circumstances but
really if you are struggling getting it out this should be the last resort. If
you break this screw extractor in there you a major problem trying to get that
out. To drill out a bolt like this it is very difficult because they are hard.
We’re going to use a cobalt drill bit if that won’t actually touch it you would
have to use a solid carbide bit but they are very expensive and very difficult to
use. Obviously it’s critical that you wear safety glasses when you do this. I’m now going to take the screw
extractor I’m just going to tap it in there gently. Ideally you’d use a tap
wrench on the end of there, unfortunately mine are both at work. So I’m just
going to use an adjustable spanner and I’m going to press in on this and then
going to try and undo it in an anti-clockwise direction. As you can see that is extracting the bolt. So they will work in some situations but they will not work in every single situation especially if the bolt is rusted in. For small diameter bolts you could use a GrabIt Pro these are made by Trend.
Firstly we use that end to burnish the bolt and then we use that end to
extract it. These have got to be used in reverse. So I’m now going to flip that
over I’m going to apply some downward pressure ensuring the drill is in
reverse. As you can see that has extracted the bolt. On small diameter bolts like this you can sometimes use a center punch.
This one is actually spring-loaded and that is very useful in confined spaces
where you can’t hit the end with a hammer. So this has actually been
thread locked in there and that was done yesterday it’s actually been
tightened so much that it’s actually rounded off the inside of the bolt. So what we need to do with this to
starts off with is to centre punch it and you’re better off doing that
straight up like so, that will give us an indentation in the bolt head. So now we’ve
got an indentation in there and I’m going to turn the centre punch on an
angle so that we can knock that around in an anti-clockwise direction. I did use quite a lot of thread locker on that and it does look like the threadlocker
is very tough stuff but we’ll just give that a few more goes, and finally that
is actually moving round we’ve actually broken the bond between the thread
locker and the bolt. Once we’ve got that proud of the surface we can then grip that with the mole grips. That’s some of the techniques that you
can use to remove rounded allen head bolts. I hope you found this video useful if
you have and you haven’t done so already please subscribe to the channel.


  • Thanks for all the ideas, but it looks nice if you had use here new bolts without rust and with threads in good condition.In practice it looks usually dramatic different – rusted bolts with damaged heads and with hard fixed and rusted threads.
    For example I was only one time successful with using of screw extractor. In several cases it broke in the hole and then is a big problem drilled it because usually has a very hard material..

  • I've always used a torx bit and it works every time

  • I just use my round bits 👍🏻

  • Trevor Graham Welch

    Blow Torch

  • great video ! thank YOU !

  • any scooter riders ? :Ddd

  • Ldog Harycokanbalz

    Use a pair of knipex pliers and be done.

  • if you need to reuse the rounded out allen bolt because you don't have another one handy i use a brand new hacksaw blade and cut a slot in the head. you can remove the bolt and reinstall with a good straight blade screwdriver.

  • Well done video sir. This will help allot of people.

  • I've hammered torx bits in rounded Allen's before

  • One of the best tools I've ever purchased was an induction heater! The mini ducter is awesome especially when you can't use a flame to heat a bolt! It will get a 1/2 bolt glowing hot in less than 30 seconds!

  • Nice one mate

  • I would be interested in seeing how you would deal with a small hex socket cap screw that is tightened into a hole with fairly tight sides and is below the surface level whereas the threaded shaft is very slim having little strength. I am refering specifically to the 4 wheel drive hubs installed in American pickup trucks from the '60s, to the '90s. There are six such bolts holding the turnable manual hubs on the front axle.

  • I usually use a drill and apply pressure with some type of hex key or square key and works every time !!

  • Lee Sensenbrenner

    The punch method worked perfectly for me on a recessed head bolt; without your advice, I would have tried an easy out, and I'm glad I didn't.

  • VERY informative! Educational. Thanks 👍

  • Had a hemit wrecker was leaking on the valve body on the back for recovery ops the bolts were hex and filled with rust and dirt they were also in an assembly used a drill to get one of the bolts out the others were so stuck I gave up

  • Doug's Welding & Fabrication

    Good Grief… you made that look easy ! It never goes that way for me.

  • Every situation like this is solved with a Dremel cutting disc and a flat head screwdriver

  • David Stokes-Lopez

    Great video!!!!
    Thank you!!! 🙏

  • Good video. I think Allen head bolts look great, and are good for confined spaces or where clearances are an issue. However regular hex bolts work in almost all cases and strip far less easily.

  • You hit on just about the most important action in removing a broken or stuck threaded piece and that is to use a backward turning as well as the forward turning action to prevent rust and other metal particles from causing the tread to gall or weld the parts together. use this action throughout the entire extraction process. I haven't seen others demonstrate this most important action. Thanks!

  • Oh cool. How do I remove meth addicts

  • How do you avoid work hardening the stainless steel?

  • Hit the top with a ballpean hammer then tap your hex socket into it.
    Works all the time for me.

  • One way you missed as a millwright I have removed tons of stripped allen head bolts by hammering in a torx bit they dig into the corners giving no slippage

  • Shut up and take my subscribe

  • I’m always surprised at the number of these that talk about penetrating fluid that a lot of people equate to wd40. Wd40 is a very poor penetrating fluid. 50-50 atf and acetone and a little bit of time makes an enormous difference. If it moves a bit but not much then that penetrating* fluid will get in. I can only guess how many YouTube searches will happen after this.

  • Torx bit and hammer FTW.

  • I just insert a small screwdriver next to the allen key and can usually get it out by wiggling the screwdriver until it locks into place then just undo slowly. Doesn't work every time but about 85% of the time it does.

  • andrew latchford

    I always. Find that bolts like this are best left alone.I just fuck off and get pissed and forget about wha I was asked to do.

  • After heating the bolt..can you use something or a spray that comes out liquid, or a very cold liquid and apply it to the center of the bolt…which I think will 'shrink' the bolt to make it easier to remove…

  • I appreciate you sharing all your little tricks they have been helpful from time to time so I wanted to share one of mine with you I had a grub screw that was set deep glued way too much from the factory and I totally stripped out I couldn't get it with the reverse drill bit or anything so I wound up taking J-B Weld you got to use the strong one the one in the black and red tube make some little bit together and put just enough on the head of the Allen key let it Harden and I got that son-of-a-b** out good Channel keep it up man

  • Fathma Sameer

    Very useful video thanks

  • Wow I didn't think that little center punch would work.

  • It looks like none of them were stripped or rounded off

  • Nicely done. Thanks for taking the time to post it. However, may I suggest a correction for future videos? My teacher of technical drawing class in collage, used to say “if it takes a nut, it is a bolt. If not, it is a cap screw”. Also several fasteners shown are machine screws and not bolts.

  • If the bolt head sticks out, use a pipe wrench. The wrench will grip more as you apply pressure

  • I have only ever used one thing: get a Torx bit slightly larger than the hole, then beat it into the rounded hole with a hammer. You now have a fully functional Torx head screw, simply attach your screwdriver or wrench to the bit and turn the screw out

  • Why does the thumbnail look like some Mars artifacts videos ?

  • Thomas Broking

    I have used a hacksaw on protruding bolts and cut a slot for a flathead screwdriver. Then the recessed ones i have a bigger flathead and sing it in with a hammer. A couple times it has saved me from drilling them out

  • oops…I didn't realize there was metric and imperial Allen keys. that must be why my bolts are rounded 🤦‍♂️

  • RicktheRecorder

    Technically, I'd call all of those fastenings machine screws, not bolts.

  • You said not to drill stainless steel bolts too fast or they will get hot and work harden does that mean you can't use heat to loosen those up as well or is it different from getting friction heat from the drill.

  • Nice video thanks for posting and sharing your knowledge and techniques..

  • Tediuki Suzuki

    Good stuff but I was surprised that the centre punch only came last . One can centre punch the flats roughly back in to the head and either use an Allen key socket with an impact driver or gently hammer an allen key in and give it a go . Otherwise if it's really bad then forget the centre punch and gently hammer a torx key socket in and use an impact driver .

  • Would tapping in a left hand left into a hex cap head work you reckon? Got two rounded bolts which are in awkward places

  • Promotions Only

    When you drill off a bolt head it’s best to file two opposing sides so you can deliver more surface area.

  • Jonathan Tenorio

    Great video but I wouldn't drill all the way inside the screw. The threads from the item you have the screw in could get damaged

  • Great show again, mate.

  • Anders Johansson

    Is that a Bacho wrench? I sure wish we could get them in the US. I've gotten mine through relatives and trips to Sweden years ago.

    Good tips and a good refresher. I liked the spring loaded center punch. I'm going to have to get one to add to my tool collection.

    One thing I remember growing up on the farm was Dad used water when drilling metal. A sharp and cooled drill bit always cut more aggressively than using cutting oil. The heat is what would do the drill bits in. I was always mesmerized at how it cut like butter and long steel spirals like spiral pasta would come out.

    The drill press/work area was a bit rusty, but a little wipe down with WD-40 took care of that.

    Glad I came across you video and am now subscribed.

  • Not too bad overall but that last bit with the spring-loaded centrepunch…pure fiction, sorry.

  • As of lately, as the welder is almost always set up… when I don't need the screw any more I directly use the weld on method. It's quick enough, and has never failed. Going through more than one method because of a fail is almost always slower.

  • When using a left handed drill, set it to the lower speed (or screw speed if you will). You want biting and turning more than drilling into the screw. Great video. I especially like the advice to use the hex wrench when using a pair of vice grips in order to avoid crushing the head.

  • Just weld a nut

  • Great information

  • I'm taking out a 55 foot-pound tightened bolt. Ya all better have some legendary methods

  • Or with small ones just use superglue.

  • Chris Kleczynski

    "there's every chance"

  • I've had some success using a star or torx type key slightly bigger than the allen key size and hammering it into place! Great video though emphasising the need for the correct tools for the job, thanks!

  • Having a rough time getting a stripped alan screw out of a riding Lawn mowers motor shaft pully. Got 2 out of 3 and the 3rd wont move.

  • one of the most informative videos ever!

  • Great stuff!
    Only other trick I know is cut a slot in it and use and impact driver.

  • Bastos Reviewer

    Great metheods and techniques!

  • As my dad used to say it, if all else fails, pour gas on it and torch the whole bloody thing.

  • How to remove car door that has broken bolt ?

  • Andrew robinson

    I have a lot of rc models some use the button head easiest way iv fount to get them out when they get locked up is to grind a flat head slot in and use an impact driver works pretty much every time if still don't work I give it some heat from my dremel versatip torch wich comes in super handy for heating small things up good video iv youse quite a lot of your tips and mixed a few together an have never had an issue alto I did snap a head of one of them but a little heat and pliers got it out with no damage to the threads

  • psychotikpaisano

    If you know the bolt will be stubborn tighten it first.
    This will warp the hex slot in a way it will be stronger when you try and loosen it

  • File flats on the external one to remove it

  • mtn. srl Rascu

    I have another method: I weld a nut under the bolt head with the stick , after wen is cold you can get off.

  • I had to drill one out today because the head was tilted at like 30° 😂 and the bolt itself was not

  • Now try all them steps on some rusty ones that been in for a while bet the dont work

  • brilliant mate!

  • vojamilovanovic

    When use a drill, DON'T wear gloves!

  • I'm actuallyimpressed with that punch trick….. That thing works extremely well for what it is…

  • Thank you! I was so frustrated with this DIY furniture screw and Allen wrench from America's Superstore. The screw was stuck halfway into the bookcase and then stripped! Your advice for using the grips worked like a charm.

  • Fırat Volkan Tanınmış

    trick at 4:14 saved my ass for many times! Thanks a lot man!

  • Thanks this actually worked👍

  • Hope this works for my revo 3.3 rocker arm

  • Helpful video

  • good to know but not always practical

  • Marius de Meyer

    What usually work for me is to put some valve grinding compound on rhe end of the allan key before I insert it into the rounded cap screw.

  • Drill guids and extractors go to.

  • men아직도총각

    I already know everything. Anyone can do it with sweet potatoes.

  • How do you get a stripped torque screw out of plastic ?

  • Weld a large nut to the head. Let cool and out it comes. If that doesn't loosen it then fire up a thermic lance and burn it to a molten puddle of oxidized garbage..

  • Thank u 4 sharing!

  • Catabatic Anabatic

    Good to see you calling them Mole Grips. Proper old school Mole Grips are without equal I bought loads of pairs on Ebay a few years for no money at all. They cannot be beaten.

  • I got a bolt so stubborn I’ve tried everything but explosives and the thing is I need the screw drilling it out is not an option because it’s not like I can contact the company of the product I have and say I need a new Allen screw I had to drill screw out old one it was stuck and can’t find one in size I need I doubt they will send me a bag of extras

  • Great tips, very useful!

    By the way, who's Al 'n' Ed?

  • Look here we kicked king George's ass out of Merica so we didnt hafta use that metrick system. So keep using that and eating pancreas and vinegar pie! Just kidding great and informative video

  • Awesome video. Thanks for no music too!

  • I like the part when he got the rounded allen head bolts out. I hate the part when my rounded allen head bolt is about the size of a fine pen head indented into a light fitting two metres off the ground.

  • SHCS Socket Head Cap Screws…. Not Allen Head bolts.

  • As an rc hobby enthusiast, I know see why all my hex nuts are stripping. Not the right tool for the job

  • speaking of breathing fumes, if you are planning to mig weld a nut to it, DO NOT USE BRAKE CLEAN before mig welding. The argon and brake clean produce a poisonous gas that attacks th respiratory system and can cause death. Research for further details.

  • Using a star bit just a size bigger than the hole works really great. Tap it in with a hammer and remove it with a ratchet. Easy and it's worked everytime I've done it.

  • A torx bit sometimes works. Just tap tap it in!

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