How to remove a broken bolt in a deep hole | remove broken bolt in recessed hole

In this video I’m going to take a look at a few techniques for removing broken bolts or broken studs which are deep within a hole. So I’ve got a stud in that hole that needs removing we’ve also got a sheared bolt just there that needs removing. If you see that all of these are below the surface. Then on this sump we have actually got a sheared bolt just there. The danger with trying to remove a stud like that or a broken bolt is the fact that the surrounding material is much softer than the bolt itself so obviously this is made from aluminium and the bolt is made from steel so the aluminium is much softer. Before you attempt to remove any broken bolt there are a couple of things that you can do that can make it easier. One of the first things you should do is try to shock it now I’m actually going to use a spring-loaded punch to do this so I’m just going to give that a few gentle taps. If you don’t have a spring-loaded punch like that you can use a traditional punch just give that a few gentle taps with a club hammer and that can help to free the broken bolt. can also apply some heat obviously you have to be careful if you’re using burning gear because you can quite easily melt the aluminium. You can also use some spray penetrant there is a good chance that will help. One thing that you could use is a hinge sighting drill they have a spring loaded part there which exposes the drill bit that will actually prevent the drill bits from catching the side of the material which you are trying to remove the broken bolt from. In sighting drills are normally used like that, you’ll position your hinge where you want it then you can simply use that to drill your pilot holes that will ensure they are dead central. However I’m not going to use it for that I’m going to use that to ensure that I can drill dead in the center of a sheared bolt. Take a look at that one for example you can see that that is in very bad condition if you try to use a normal chance at all of getting it started without drill bit on there you would have no slipping off and damaging the aluminium thread. For the first bolt I’m going to swap the drill bit over and I’m going to use a left-handed drill bit so I’m just going to push that in there I’ll then tighten the grub screw and then I’ll screw that back together. The actual drill bit that I’m using is a bit shorter than the one that I’ve taken out so I’m actually just going to remove the spring from that and that will still centre the drill bit. So if we try that in the end of the shaft you can see that it’s a very good fit and we’re not going to actually damage the internal threads on that. You can of course use a regular right handed drill in a hinge sighting drill but that will then mean that you will need to use a screw extractor afterwards. So I’m now going to flick the drill in to reverse and then we’re going So you can see that the left handed drill bit actually started to bite into that and it actually extracted it from the hole. If we take a look in there you can see that the threads are not damaged at all. A big problem with removing a broken bolt that is deep in a hole is that you don’t want to damage the threads in the surrounding material. I’ve actually made these which are socket head bolts and I’ve actually drilled a hole down the center of those using a lathe and I’ve actually made an M12, M10 and an M8. So we can now take this we can actually screw that into the hole where the damaged or broken bolt is until that is tight and then we can tighten up the nut that will prevent that from coming loose just gently nip that up and again I’m actually going to use a left-handed drill bit. The beauty of a left handed drill bit is that when it bites into the material there’s a chance that it will remove the broken bolt. So I’m just going to put some cutting paste on the end of that and ensure the drill is in reverse You can see that that has now started so I’m going to remove the bolt and we should have an indentation in the bolt so that should ensure that we don’t actually damage the threads on the aluminium and we should now be able to proceed and there is a chance that we will be able to remove this. Let’s give that a spray with some spray penetrant and I’ll just try again. It’s not actually been moving the bolt that time but we have got it far enough forwards now and in a deep enough hole to try a screw extractor. So I’m now going to take a screw extractor I’ll just tap that in there I’m just going to take a small adjustable, I would normally use a a tap wrench but it is at work. This time we’ve actually got that moving. It moves a little bit more, it has actually slipped out again. These are not the best quality screw extractors that you can get these were a very cheap set. I’m just going to go to the next size up. I’m just going to tap that in, and as you can see that has successfully removed the damaged bolt. I’ll just prove to you that none of these threads have been damaged. We can now take an M10 bolt and we can easily screw that back in there. With this one you’ve got absolutely no chance at all of starting the drill bit on it because it’s not at all flat. So the chances are that you’d skid off there and you’d actually end up damaging the threads. So I’m just going to give that a spray. I’m now going to take the socket head bolt that I’ve drilled a hole through the center, I’m going to screw that in there until it touches the broken bolt, I’m going to run the nut down and I’ll just nip that up. I’m going to use a cobalt drill bit for drilling the bolt because these are very tough. What we don’t want to do is go too deep into it because you don’t want to drill into the aluminium. So I’m just going to apply some cutting paste then I’m going to proceed to drill the hole. I’m now going to remove that and we’ll see how deep in we have gone. So you can now see that we’ve got that hole started and it is dead in the center of the bolt. Now that we’ve got the hole started in the dead center we can now continue to drill that without the guide in or if you aren’t confident about doing that you can always put the guide in. So I’m now going to take some more cutting paste and I’m going to proceed to drill the hole. So we’ve drilled approximately seven to eight millimeters in that bolt. What we don’t want to do is go too far in there and go through the actual aluminium casting. So I’m actually just going to try the screw extractor on that now. I’m just going to tap that in using the hammer and then I’m just going to undo that using the adjustable spanner. It does actually look like that has bit. Normally I would use a tap wrench for doing this but unfortunately it is at work. As you can see that has been removed successfully. We will now just try a regular M12 bolt back in there just to prove that the threads have not been damaged. You can see that that goes in there perfectly. Obviously before you go putting any bolts back into components like this it’s a good idea to give them a good coating using some copper grease or anti-seize compound. If you do that you can virtually guarantee that the next time you come to remove the bolts they’re not going to seize up and they’re not going to snap and you will be able to remove them very easily. So that’s a couple of techniques that you can use to remove bolts that have been broken deep in holes. I hope you found this video useful if you have and you haven’t done so already please subscribe to the channel.


He uses right instrument in wrong way. He calls it screw extractor and uses manually, not installed into drill….

The examples you show are not the result of seized threads, but of over-tightening. Otherwise, you would have had a much more difficult time extracting the remains. Please do the real mechanics of the world a kind favor and slap the p!ss out of the ham-fisted bloke (or blokes) who didn't know when to stop tightening those fasteners.

Fantastic what a great idea using a bolt with the center drilled out, retired – auto mechanic sure wish I knew that years ago, can't tell you how many bolts I snapped of and had a hell of a time removing them the drill would always walk off center, brilliant

Set your driller in speed 1 and on screw position so you can limit the power in case it bite to hard without warning.

Wouldn't a socket work better than an adjustable wrench? (Assuming there is a small enough socket to fit the bit)

9 times out of 10 when a bolt head breaks from the bolt itself its because it is galled or seized in the hole . its not because the head was weak and now you just need to grab the threaded part ( all of your examples) The bolt is usually broken FLUSH with the surface so those fancy centering bolts arent worth a shit either. But as a machinist these are all tricks your avg. Joe tries before I get it and put it in the Milling machine to get out that now chowdered to hell bolt with messed up threads . I wish it was as easy as you make it out . not slamming you or your vid , I just deal in reality.

Thanks very much, I enjoyed it very well it's a clever idea, but some times the hole or the broken bolt are very damaged, I use the welding spot way to extract it…

great ideas always start with sharp bits made to cut through the material you are removing! and if you break a hardened screw extractor off in the bolt you will need to use a mill bit to drill that out.

i used my MIG welder and stacked welds on the broken bolt until it was out enough to grab with locking pliers. then i discovered ANOTHER broken bolt beneath that them both with a MIG welder. be careful not to let the wire and puddle go into the threads.quick on the trigger, you dont want a puddle, just stack blobs of weld on each other. i did not damage any threads in my removal.

OMG…these Brits and the way they talk. They always add an extra syllable to the word aluminum ?

Sorry, I don’t mean to be rude but what did you say at 3:37? Also, is it suggested to use an impact drill for this or will a regular one work?

A highly-skilled and experienced teacher – patient, professional and responsive to Q's. I do like his technique of repeating crucial elements, like being careful to not drill through the screw into the aluminum pan! What a thrill to see the broken bolt extracted. Almost 8mil views – I'm not surprised – a tribute.

The correct method using a screw extractor or some call it "easy out" is to place the adjustable wrench on the square tang, lightly hammer the extractor at the same time unscrew the extractor. the fasteners are all metric so I guess the screws broke in some Japanese equipment. It is not necessary to lube the drill bit because it should not overheat with low rpm and you want it to hopefully have enough friction to unscrew the broken stud (screw). Never use nickel based anti-sieze on aluminum or magnesium threaded holes and also never use stainless fasteners on magnesium . I'm reminded of the time I observed a guy over-torque a screw breaking the head off so to avoid a ton of paperwork with the NRC (this was at the San Onofre nuclear power plant) he applied super glue to attach the broken head onto the screw stud and nobody would be the wiser.

Good video but keep a steady finger on that trigger on the drill. That on off on your drill is wearing your drill so many times faster. A steady trigger pull is always best. some of the guys in my shop do the same thing and their drills last barely a year. I've had drills for years.

Dude, door hinge sighting drill bit set $8.99 plus left handed drill bits set $19.99= the most centered beautiful holes in broken 3400 v6 exhaust bolt studs ever!!! New studs went in like butter due to no damage to threads…Thank you!!!!!

Everything you need is at harbor freight

Well my situation is not as easy as how he's doing it. My bolt is broken and a small part of it maybe 2mm sticking out. No threads on the part sticking out and I only have about 5 maybe 6 inches of clearance. There's no room for drilling and no room to hammer in an extractor. 🙁

Thanks for the great educational video. My technique usually involves excessive use of four letter words and numerous objects being thrown around my shop and stomped on and kicked, and holes punched through walls, and is generally not quite as effective as yours.

I have just sheered a 20 year old doughnut gasket bolt on my Toyota yaris today. I gave up. Couldn't reach the bastard to drill it out. Plus I was laying in a puddle because it decided to piss it down. I spent 8 hours on it lol

Another method for removing broken bolts is with a mig welder, best method I've ever used. The video is here on YT.

Spent 25+ years Flying and working on airliners as a Maintenance Engineer. We had a small but well equipped Machine shop and 1 Master Machinist on duty daily for tool making. You would be shocked how many times hardware broke or melt/fused with another part…. we had speciality tools like above made to make repairs. In addition the Machinist would make special wing structural repair Plates from Boeing/Airbus drawings that were Hy-Locked to the Wing Spars. Good Video…thanks for taking the time to teach.

I also use the extractors with the handle from my tap and die set to add turning force as well as pushing force while screwing the screw extractor into the left over part of the screw. THis can also be done with a drill press with it turned off, using the head to apply force. When working at a repair shop I moved from station to station removing bolts and screws other techs could not remove. Also add a little more lube at the first sign of movement to not gall the threads as you start the removal process the heat generated from the removal will often wipe out the threads if you do not add lube after the first sign of movement. A good set of screw extractors, and impact driver and left handed drill bits are good to have in any shop.

Wow that’s a great tip I wish I had the leth to modify the socket bolts. You know if you did a set of sae and metric bolts you have a nice home business item to sell. And if you supply left handed bits you have a kit anyone would buy. I’m in New Jersey USA let me know.

I am using a stick welder on a broken stud below the surface of an aluminum block. What electrode should I use? 6013?

Great ideas. Usually on broken bolts they come to you after they destroy it with a punch and expect you to get it out.

I have removed a lot of broken exhaust manifold studs and have found that by drilling right through the offending stud/bolt it kind of shrinks the stud a little and makes the extraction much easier, also I used a parallel shaft extractor which worked every time, I believe that the tapered ones expand the part you are trying to extract thereby making it more difficult. Nice video though.

Excellent thanks for time you took to demo this ,and now i have to remove the remains of a star bolt from an alloy casting on top a mercedes strut where they use some kind of coating to seal the bolts !

I haven't had much luck with these methods. Mostly because i am not the best at controlling the drill. If you happen to be like me and its a easily removed and transported part. Take it to the local machine shop and get it removed without first trying it. If you mess up the hole or broken bolt then they may not be able to help

That is brilliant. I think I’m going to make myself a set of centering bolts on my pillar drill tomorrow.

I'm 56 born July 4th, 1963. I've been working on all kinds of things bicycles cars you name it and all my life, never seen these techniques before extremely smart thank you.
God Bless ?? Y'all Jimmy in NC….

When using the screw extractor (or "ezi-out" as sometimes called) it is best to do so vertically so you can apply pressure downward whilst using the wrench to turn it. The pressure helps to press the extractor into your drilled hole. Yes, I have used this technique several times. Can also be used to remove a spark-plug (centre electrode broken out) from a cylinder head. Use plenty of grease to catch metal shards that may otherwise enter the cylinder.

Thanks mate!! I’m going to be using a combination of these techniques to get a cylinder head bolt out that has sheared off in the engine block of my Subaru WRX. Never thought about combining my left handed drill bits with my hinge guides! May end up making some of those bolts with through holes and locking nuts for this project!

Excellent video.
I don't know why I'm watching this, I seem to have become an expert at removing broken bolts over the years.
Friendly advice: When tapping the extractor into the bolt, I grab the extractor with Vise Grips and apply a bit of counter clockwise torque to nudge it in tight. Works like a charm!

Like all your other videos …… simply brilliant!! You’ve got me out of jail countless times with your knowledge & skills. Thank you ??⭐️

Fab. A great watch. Thanks.
Was the last bolt high tensile? I’ve taken the head off a high tensile bolt that fastens the front (chain) sprocket to the drive shaft on a motorcycle. It is now recessed and the shaft turns, of course which adds complication.. Any tips would be gratefully received.
A very satisfying watch.

I got some broken bolt with something similar, the bolt broke inside the hole, and I also like you to apply the drill hole and extractor on the broken bolt.

I had spray penetration oil and made it soak in oil for about 30 minutes then I tried but the bolt really stuck that I even break the extractor into the broken bolt too!

I almost lost hope to it, or any suggestion?

Thank you for reading!

Thanks! Did this years ago on a valve cover bolt. My hole was way off center but the easy out still worked; however this time I need more help as the hole is deeper and a higher torque bolt. I will be at the parts store in a minute. Hope I can find something that works like your hinge starter tool. 🙂

I need to remove aluminum bolts from the bottom of my block on my bmw. Are aluminum much easier because of how light the metal is? Im thinking of using this method.. definitely do not want to pay BMW if i can do the job for hardly any $$$

As a mechanic I have worked on Army tanks and other tracked vehicles along with semi trucks. Worked for a dealership working on cars and trucks. The last 35 years I have worked on aircraft from the auto pilot to the toilets, currently working in the engine shop building Rolls Royce RB211, GEnx-1B, and CFM 56-7 turbo fan jet engines. So I have seen a lot of tricks to get things done that only a quality result acceptable. I can measure down to millions of an inch using a lens and lights. So my experience is quite broad. You have taught me a few new tricks which is rare. I knew about left hand drill bits as I have had many call B.S. on that lol. The hinge guide was a slick trick . The center drilled bolts as guides was a nice professional touch. Excellent video.

Will using copper never seize on a steel bolt put into aluminum cause a chemical reaction, or breakdown that will deteriorate the bolt or aluminum part and cause problems down the road?

I'm trying to split a scooter engine (GY6 50cc) made from aluminium to replace the timing chain. I've removed the only bolt that holds the parts together but they're still stuck and I can't separate them. Any advice?

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