Seven ways to unscrew a broken bolt or stud

Personally, I have repeatedly encountered the problem when a bolt or stud breaks at the root. Moreover, I am not some kind of auto mechanic or mechanic. I say all this to mean that this quite happens to an ordinary person who periodically deals with technology or other technical parts.
Well, since you find yourself in such a situation, then don’t despair - everything can be fixed. I offer you seven ways to get out of this situation and free the thread from a broken pin or bolt.

Preparation before turning out the fragment

But don’t rush to start unscrewing right away. Before doing this, you need to take steps that will make your efforts easier.
First of all, spray the broken area with penetrating lubricant. This can be any “liquid key”, WD-40. Let's wait a little.

Next, in order to slightly relieve internal stress, we use a gas burner to thoroughly warm up the fragment and the area around it.

Well, then let’s move directly to unscrewing the broken pin or bolt.

Method 1: Flat head screwdriver and hammer

This is the easiest way, but it is not always suitable. In about half the cases, the pin breaks off with a fragment sticking out, which is just where you can get caught.

We take a flat-head screwdriver, press it against the fragment and, using impact movements at an angle in the direction of unscrewing the thread, carefully turn the fragment.

This method is suitable if it does not require much effort to unscrew. If the effort is not enough, then move on to the second method.

Method two: try to unscrew it with a chisel

This method is similar to the first one, but instead of a screwdriver we take a chisel. In the same way, we rest against the splinter and use percussive movements to turn it out.

A chisel makes it possible to create more force compared to a screwdriver.

Third method: core and hammer

If the bolt fragment does not have splinters, or even the breakage occurred just below the final surface of the thread, then you can try using a core.

We rest the core against the surface of the fragment with an offset and, with blows at an angle, we turn it out until the fragment can be hooked with pliers or another tool.

Fourth method: weld the nut by welding

In my opinion, this is the most effective and fastest option, but only if you have a welding machine. Its essence is to weld a nut onto a piece of bolt on top.
So, to do this, take a nut, but not the same size, but a couple of units larger. That is, if the broken bolt was 10, then take a nut 12. This is necessary for a better and larger welding site.

Holding the nut with pliers, we place it on the fragment, but not in the center, but offset. Using an electrode, we weld the stud and nut to one side inside the nut.
Then, after cooling, unscrew it with a regular wrench.

Fifth method: unscrew the pin with an extractor

Here you will also need a specialized tool specifically designed for unscrewing broken studs and bolts - an extractor.

We center the pin so that the drill does not run around when starting to drill.

Drill a hole of the appropriate diameter for the extractor.

We insert the extractor into the hole and unscrew it with a key.

Sixth method: drill out the fragment

The method is to select a drill according to the lower diameter of the stud thread and drill it out. A very difficult method that requires skill.
First we go through a drill of a smaller diameter.

Then we drill as close as possible.

We knock out the fragments and remnants of the stud with a flat screwdriver.

This method of removal is not always worth the effort, but it deserves your attention.

Seventh method: drill a clean hole and make an insert

The most time-consuming and expensive method of all. But there are times when this is the only working option to return the node to working condition.
We drill out the stud cleanly along with the thread.

We cut a new thread with a tap.

You can finish here if the design now allows you to select a thicker bolt or stud. If not, we buy an insert or order it from a familiar locksmith.
Lubricate the external thread with thread locker and screw it in.

Stitch flush.
What method did you use? Write in the comments, I think your experience will be interesting! All the best!

The node has been restored.

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Comments (73)

#1 Guest Andrey Guests 26 April 2018 18:07
24

take a left hand drill and drill a hole, you never need an extractor :)
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#2 Guest Alexey Guests 26 April 2018 18:45
30

There is the simplest, most trouble-free, fastest and probably still the only way.
everything else is nothing more than fantasy. The pin will never be turned out with a chisel or welding - nothing!, since it has already broken for a reason, it sits sooooo firmly!
drill with a small drill, exactly in the center, then use a drill to drill the outer diameter of the thread minus the pitch and that’s it, usually the threads free themselves in 70% of cases, but if the stud is tightly rusted, go through such a thread with a tap. Usually, if everything is done correctly, the thread is as good as new and this process takes only five minutes.
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1. #3 Guest Andrey Guests 26 April 2018 21:48
  24
  
  He worked in an underground mine for 23 years on foreign self-propelled drilling rigs. I can say with absolute confidence that all of the above methods are completely EFFECTIVE. And exactly in the order as listed in the note.With frequent collapses, I personally unscrewed hundreds of kinks in bolts right in the face, using a chisel and a core (sometimes with a screwdriver, and sometimes with my hands), but this is provided that the bolts are branded from normal steel, and if there is a mine sharpening made of rolled piece that stretches into the thread, then you drive the car to the garage and further down the list - first welding, then (if that doesn’t help) - drilling. So the author listed everything absolutely correctly.
  
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  1. #4 Yu.S. Guests May 9, 2018 00:18
    5
    
    Right! Everything goes away with different friction problems.
    
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2. #5 apavp Guests 26 April 2018 23:04
  4
  
  Welding is a great help - fast, convenient and safe, all you need is a welder. I unscrewed a piece of the fitting from the caliper, which was broken off not flush, but 5 mm deep.
  
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  1. #6 Rustam Guests 7 May 2018 18:28
    8
    
    I can add welding to the method, under the nut that you weld to the stump you need to put a cardboard with a hole under the pin. Then after welding, the cardboard burns and a gap is formed between the nut and the base, which makes it easier to twist back and forth. (The cardboard is usually a piece from a pack of cigarettes, just right )
    
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3. #7 T2018 Guests 26 April 2018 23:18
  5
  
  You will never hit the center exactly; usually the thread always gets touched. You should immediately go for a larger thread diameter, for which there are repair studs on sale (if the stud is cut off).
  
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4. #8 Guest Valery Guests 26 April 2018 23:39
  4
  
  It is impossible to get very precisely into the center of the crease and when drilling with a drill there will definitely be a displacement somewhere.
  
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  1. #9 Ramil Guests 21 September 2018 20:11
    5
    
    If it breaks off below the plane, you can grind the jig so that you can drill exactly into the center.
    
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5. #10 passerby Guests 27 April 2018 07:32
  1
  
  Alexey, in 90% of cases you damage the thread because there is no 100% hit in the center, the breakage is not even. All the ideas proposed by the author work. When struck with a screwdriver, chisel or core (has TS divided these cases based on the number of points?), the “siskin” comes off and unscrews much easier; when heated and welded, due to the difference in materials (rust has a different expansion point), it also unscrews more easily. When drilling with a “left” drill, in addition to the effort to unscrew, heating occurs, as well as light shocks (or rather vibration) and the “siskin” unscrews itself during the drilling process. the most effective way, in my opinion, is to weld the nut
  
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6. #11 Welding Guests 28 April 2018 18:35
  6
  
  Sometimes I used welding. When welding the nut with the rest of the stud, a spot heating of the latter occurs. Everything burns inside and there is practically no effort when turning it out. The left drill is the same thing, but it’s not always at hand.
  
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#12 Guest Alex Guests 26 April 2018 19:01
17

Use a grinder or Dremel to make a slot and unscrew it with a flat screwdriver
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1. #13 T2018 Guests 26 April 2018 23:13
  7
  
  Even if the body of the bolt is cut off, what kind of screwdriver can it be? I'll give you a million if you can remove even one stuck bolt this way!
  
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  1. #14 Guest Vladimir Guests 27 April 2018 14:27
    5
    
    I have used this method many times. For screws up to M5 I use a drill with a thin disk, for large bolts I use a grinder with a 115 disk 1mm thick. A cut is made along the axis of the bolt, like a screw with a depth of 1-3 mm, and the metal on both sides often catches in the meat, but usually this is not critical. Then a VDshka and a screwdriver with a suitable slot
    
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#15 Mukhtar Guests 26 April 2018 19:23
7

The HP or liquid key cannot be lubricated before frying; on the contrary, only after frying, then the stump in most cases will unscrew without effort.
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#16 Guest Valery Guests 26 April 2018 23:36
6

Using sandpaper, we grind a thin reamer like a 4-sided long pyramid. We drill with a drill all the way through the broken end, being careful not to touch the thread. We hammer the ground reamer into the hole and turn it inside out at the square end. Be sure to drill right through.
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1. #17 Guest Sergey Guests 28 April 2018 12:56
  1
  
  Exactly! This is the only real way that does not break the thread. We have never been able to do anything with chisels and cores - only the part itself ends up being ruined.
  
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2. #18 Guest Andrey Guests 2 May 2018 19:00
  3
  
  All of the above options have a right to life, but only a sharpened tap for a pyramid, or a triangle for a cone, really helps. Having pre-drilled the crease.
  
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#19 T2018 Guests 26 April 2018 23:37
8

In 90% of cases, it is cut off due to clumsiness, which tears stuck nuts with meter-long wrenches. If you see that a nut or bolt does not go, calm down, breathe, then apply a bucket or diesel fuel, kerosene... after a couple of hours, try rocking (back and forth ) to unscrew, if it doesn’t move, pour some more and wait a few hours, then rock again until this system fails. If you have a torch, then the matter is simpler, you need to heat the nut red-hot (but not the bolt, because it will cut off even more easily!) it unscrews perfectly, no matter how rusty it is, but if you need to unscrew the bolt, then you need to heat the metal around the bolt red-hot , it will also work out just fine. I've been twisting it like this for twenty years, but it doesn't work, only if everything has turned to dust, then just drill it out.
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#20 Guest Denis Guests 27 April 2018 04:26
3

On a VAZ 21093 I removed the cylinder head, the bolts had a hex head, i.e. The 11mm hex needs to be inserted into the head of the bolt. all the bolts were unscrewed using the most ordinary pipe, and one (central) in the front as the car was moving really did not want to leave its place. As a result, having crushed all the edges, I decided to saw with a grinder, fortunately the bolt is outside the mechanism and the space allows. Having cut through half the bolt, I noticed that the disc no longer fits into the cut. Because of the heat, he decided to leave his place, even by hand. It should be noted that it was -10 outside, and, apparently, the temperature difference played a role.
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#21 Vyacheslav Guests 27 April 2018 08:17
3

Even under Soviet rule, in Dubovka at a repair plant, I encountered a repair spiral. Its cross-section is in the shape of a rhombus. We drill out the stud along with the thread, cut the next largest thread and screw the spiral into it. At the end of the spiral there is a tail bent perpendicularly. We take a rod, saw a groove at the end for the tail, bend it in half and get a device for screwing in a spiral. (the mechanics had ready-made kits) Tricks:
1. The pitch of the new thread must match the old one.
2. The diameter of the “screwing” rod should be equal to or slightly less than the internal diameter of the spiral.
The spiral is screwed in until the “tail” breaks off; by the way, the mechanics didn’t bother removing it.
If you sharpen the spacer, as the author suggests, to the next diameter, then you will just get a spiral, otherwise you need to make the spacer several sizes larger, which is not always acceptable.
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#22 Dmitriy Guests 27 April 2018 09:29
2

Here's how to get the tap out of the duralumin body? Maybe you can tell me what.
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1. #23 T2018 Guests April 27, 2018 12:24
  1
  
  You can try to cut two beaks at the end of a steel tube (tube diameter = hole diameter) so that they fit into the chip channel of the tap and twist to unscrew the tap. If not, then just break the tap in parts, sticking a suitable bit again into the chip channel of the tap and pulling out the broken pieces with a suitable neodymium magnet.
  
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2. #24 Dmitriy Guests 27 April 2018 14:32
  2
  
  So weld something to it, or as written above. But breaking out a tap in pieces is not a pleasant task. There are taps that are not too fragile.
  
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3. #25 Alexander Nikolaevich Guests April 28, 2018 00:38
  1
  
  In the magazine "Behind the Wheel" about 20 years ago there was an interesting solution: how to unscrew a pin from an aluminum cylinder block. I tested it and it works: you need to drill a stud and pour nitric acid into the hole, which easily dissolves iron while remaining neutral to aluminum.
  
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4. #26 Kornei Guests April 28, 2018 11:05
  1
  
  Etched with nitric acid, a slow but sure method!
  
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  1. #27 Guest Anatoly Guests May 8, 2018 07:11
    0
    
    where else can I get it (acid).... Not for sale, because... You can make some kind of V.V. out of it.
    
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    1. #28 VYACHESLAV Guests July 6, 2018 08:38
      3
      
      Avito help, I found nitrogen there
      
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5. #29 Sevastopolets. Guests 2 May 2018 15:27
  1
  
  A steel stud, bolt, tap... is removed from aluminum alloys by etching with 30% nitric acid for several hours. The resulting oxide protects the base metal from destruction.
  
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#30 Guest Mikhail Guests April 27, 2018 11:20
5

The other day I was removing the exhaust, changing the catalyst, all four bolts attaching the exhaust system to the manifold were cut off and stuck to death, although I poured plenty of liquid wrench on it and LM-40 (analogue of VDeshka from Lika Molly) heated it and tapped it.I was hesitant about buying and replacing the exhaust manifold, but I decided to try to fix the original one, fortunately I had the bolts from a similar car. And it worked!)) I drilled everything out and restored the threads. True, I had to suffer for a day in a hole with my hands upside down. From the beginning, I drilled all the broken bolts through with a 2mm drill (I bought 3, one broke), then expanded with a 3mm drill, after 5mm (M-6 bolts), then with new taps in swing, generously lubricating with blue grease, a quarter turn at a time, slowly unscrewed the rest bolts, well, as soon as I unscrewed them, I broke them out piece by piece with a sword, then with a second sword I went through the threads and bolts with a tool, and everything was tightened as it should be! The only thing I can recommend is to use only new drills and sockets, because... metal fatigue has not been canceled by anyone (who has studied metal science in the course), otherwise you can break a “high-quality Soviet sword” that is 50 years old in the hole at lunchtime, complicating your task. Maybe someone will find my experience useful. Good luck.
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1. #31 T2018 Guests April 27, 2018 12:37
  5
  
  It is useless to pour VD on the bolts or studs of the exhaust flange, there almost welding results from the high temperature, it is best not to be lazy and remove the manifold and then, in a convenient position, heat the body of the flange near the bolts red hot (but in no case the bolts themselves, because they will release and immediately cut off!), after which the bolts are easily unscrewed while swinging, if there are studs on the flange, then only the nuts need to be heated. The time spent on removing the exhaust manifold is more than compensated by the absence of hemorrhoids from drilling out cut bolts or studs.
  
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2. #32 Guest Gregory Guests 13 October 2018 20:11
  1
  
  Vinegar helps to unscrew burnt nuts. Moisten and wait a little.
  
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