How to unscrew a broken stud using an extractor

There are quite a few ways to remove a piece of a broken pin or bolt. But this method can be called traditional or classical. Here you will not need any initiative or ingenuity, but only simple execution of certain, long-practiced instructions.
I won’t say that this happens regularly, but there are quite a lot of cases of broken studs during repair work in auto mechanics. And for these cases, they have already come up with a special tool called an extractor.
They are usually sold in sets of different diameters, a universal repair kit so to speak.
How to unscrew a broken stud using an extractor

Each extractor has its own number.
How to unscrew a broken stud using an extractor

On top of the box or inside, in the instructions, each number has its own applicable range of values. In this case there are three lines. The topmost one is the serial number. Below is the initial and final hole size for which this extractor may be suitable in inches. And the last line is the initial and final thread size.
How to unscrew a broken stud using an extractor

Working with such tools is straightforward. First, drill a hole in the center of the piece.Next, insert the extractor and use it to turn out the thread fragment.

Removing stud fragments using extractors


Let's move on from theory to practice. I don’t have any specially broken or stuck threads, but I will do a complete simulation to clearly show the whole process. I prepared a thick-walled profile with holes in which threads were cut. I prepared bolts for these holes.
How to unscrew a broken stud using an extractor

I take these bolts, roughen the threads with a hammer and tighten them with a wrench into the profile. Everything is very tight and you won’t be able to tell me that this doesn’t resemble real conditions one bit.
How to unscrew a broken stud using an extractor

I use a grinder to cut the heads flush.
How to unscrew a broken stud using an extractor

The first thing to do is drill a hole exactly in the middle. To do this, take a core and center a point so that the drill does not jump at the beginning of drilling.
How to unscrew a broken stud using an extractor

Punching point.
How to unscrew a broken stud using an extractor

Now you need to drill a hole, the diameter of which should be approximately equal to half the thickness of the bolt. In this case, the bolt is M16, its thread diameter is 16 mm. We take a drill half the size and drill a hole with a diameter of approximately 8 mm.
How to unscrew a broken stud using an extractor

It turned out pretty straight in the center.
How to unscrew a broken stud using an extractor

We insert the appropriate extractor and begin rotating to the left. To turn the extractor, a wrench is usually used, but if you don’t have one, an adjustable wrench will do just fine.
How to unscrew a broken stud using an extractor

As soon as the extractor makes a hook, the thread fragment itself will begin to turn out.
How to unscrew a broken stud using an extractor

I hope it's clear. Now we move on to the larger bolt. Everything is exactly the same: we drill a hole in the center.
How to unscrew a broken stud using an extractor

Insert the extractor and unscrew it to the left.
How to unscrew a broken stud using an extractor

To release the tool, we clamp the piece in a vice or hand clamps. And turn the key to the right side relative to the piece of thread. It's pretty easy to unscrew everything.
How to unscrew a broken stud using an extractor

This is a simple method that has been proven over the years.
How to unscrew a broken stud using an extractor

I would like to add that you should not drill a hole with a diameter that is too large relative to the thread, since the thin walls in the stud will flare the thread itself, which will negatively affect unscrewing.
Particular care must be taken when handling small-diameter extractors, as they break very often.
If the fragment does not want to give in, heat the assembly and spray it with lubricant.

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Comments (4)
  1. permanent traveler
    #1 permanent traveler Guests July 25, 2018 02:42
    1
    I drilled half a bucket and used up extractors in 2 days, while I extracted a piece of an M6 bolt from the combustion chamber! They are molded from ...outside!
  2. Guest Sergey
    #2 Guest Sergey Guests 31 August 2018 19:26
    1
    I bought three sets of similar “extractors”, and all are made of g.... The nail will probably be stronger...
    To unscrew the broken pieces, I make a conical tetrahedron, hammer it into the drilled hole, and only then unscrew it with a wrench.
  3. Yuri Vasilievich
    #3 Yuri Vasilievich Guests 17 May 2019 23:08
    1
    Perhaps this is relevant for this case, but I would like to see how you, dear one, will unscrew a stuck bolt, for example, an engine manifold. After all, people will start trying and think, oh, how simple everything is. And when this extractor bursts in your bolt, then drilling it out will be oh, how problematic it was tested on yourself. And you have to re-drill and cut it to a larger size if space allows. And if not, then AMBUSH and replace the part and get money.
  4. Ozrokov Anzor Mikhailovich
    #4 Ozrokov Anzor Mikhailovich Guests 15 March 2020 19:21
    1
    To be honest, the method is only suitable for ordinary bolts from a hardware store. Try drilling a hardened bolt or stud first, and then we'll see :-)