Whatever durable metal, we all know that even he sometimes cannot stand it and fails at the most unnecessary moment. One of these situations may be scrapping fastening element, in particular bolts and studs. There is nothing worse for a person with a wrench to see a broken bolt, part of which remains in the screwed-in element. And then the extractor comes to the rescue, do not be alarmed, its name is much more complicated than its design. Let's talk in more detail about working with it and its features.
Device and types of extractor
There is nothing complicated in the design of this tool. In appearance, it is a steel rod at the end of which a left-hand thread (or wedge) is cut; the shape of this miracle tool resembles a beard or a puncher. There are quite a lot of sizes, the larger the bolt being removed, the larger the extractor. I advise you to always buy this tool as a set, because you never know in advance which bolt or stud will fail. The most commonly used sizes are from M1 to M16.
By design features extractors are divided into:
- Wedge type. They are a cone with edges and work on the wedge principle. The extractor is driven into the pre-drilled part of the stuck bolt and then turned out with a key. Working with it, of course, is simple, but before drilling a hole, be sure to keep in mind that you need to drill strictly in the center, without moving the hole to the side. Otherwise, all of the extractor's rotational force will be displaced and you will not be able to remove the broken bolt. You can also break the extractor itself.
- Rod type. Made in the form of a rod with edges, very similar to a wedge-shaped extractor. It gets hammered into the broken part and is turned out with a wrench. Like the first type, the extractor can be quite difficult to remove from an already unscrewed part.
- Spiral type. The most common and effective extractor for unscrewing broken bolts. The same cone only with a left-hand thread (right if we unscrew the left-hand bolt). The extractor is not clogged, but is screwed into the bolt hole, wedged together with the part and removed.
The operating principle of the extractor for unscrewing broken bolts
If you have read the description of the types of this tool, then you can already imagine the whole simple procedure for removing bolts. But without systematization, this material will be incomplete, and let’s look at everything in more detail.
The first step is to mark the center of the broken bolt. For this we need a center punch and a hammer.
Then we drill a guide hole for the extractor. When drilling, be careful and do not move the axis of the hole to the side. Experienced craftsmen It is recommended to drill to a depth of three drill diameters.
Insert the extractor into drilled hole and tap it with a hammer to securely fix it. After this, use the tap driver to begin screwing the extractor into the broken bolt. When it goes all the way, it will begin to unscrew the bolt. When working with the extractor, rotate only around its axis, and in no case shift the axis, otherwise you may break the tool.
Once you have unscrewed part of the bolt, you can use pliers or a clamp to continue unscrewing the broken element more quickly.
- In order to remove a bolt or stud faster, they should be heated.
- If the screw thread is stripped, you can try to unscrew it with a hex key. There is a high probability that the attempt will end in success.
- When working, use lubricating oil or acetone.
- Using a reverse thread drill bit can easily remove the broken piece.
- You can use a core and a hammer. Holding the core at a 45 degree angle to the part, hit it counterclockwise. Perform the procedure in several places; if the bolt does not budge, you should use another method.
- If all attempts to unscrew a bolt or stud fail, you will have to drill a hole larger diameter and re-thread.
A rusty bolt, if too much force is applied, may break when unscrewed. This situation becomes a problem for any beginner, because it seems that now the bolt cannot be unscrewed with any tricks. But in fact, you can always choose an approach to solving a problem.
Use of lubricants
Before you start trying to remove the broken bolt, you need to fill it with liquids to dissolve the rust. It also wouldn't hurt to use some kind of lubricant. You can use WD40 and machine oil. These products have never failed and are used everywhere.
When the bolt is filled with lubricants, it needs to be tapped from time to time with a small hammer or some other tool. This is done so that the lubricant and rust dissolving agent penetrate deeper into the threaded connection. After this, unscrewing the problematic bolt will become much easier.
Make a slot for a screwdriver
Unscrewing a broken bolt is not an easy task in any case. We'll have to try. One method is to cut or drill a slot for a heavy-duty screwdriver. Any tools can be used for this. For example, a thin metal drill. If you can make a groove, then the problem will be solved.
Place a screwdriver in the groove, press down on it with your hand and at the same time unscrew the bolt.
This method of unscrewing the problem bolt is the simplest and most preferable. You should start with this, and only if you can’t make a groove for a screwdriver, you can try other options.
Weld or glue the handle
Another way is to glue, or better yet, weld a metal rod to the bolt. This requires skill and is not always appropriate. However, in some cases, this method of unscrewing a broken bolt works with a bang. Instead of a metal rod, you can weld something else.
For example, another bolt or metal door handle. The main thing is that the welded part allows you to easily unscrew the broken bolt.
Screw in a smaller bolt
The third way is to first make a hole in the bolt and then screw in the thread. It is clear that after this you can screw a whole, unbroken bolt into the thread. If everything works out as it should, unscrewing both bolts will not be difficult. You can use a standard key for this.
By the way, it is advisable to choose the second bolt with a different thread. That is, if the problem bolt has a standard right-hand thread, then it is better to choose the second bolt with a left-hand thread. And vice versa. Otherwise, the screw-in bolt can be installed in the thread with aggressive glue.
Drill out the bolt completely
The fourth method is complete drilling. The key to success is to work gradually and make the first hole in the center. If the hole is shifted to any side, then when approaching the thread, you will also have to drill out part of it.
After this, the thread will be damaged. If the hole is strictly in the center of the bolt, then its walls will thin out evenly and the thread can be kept intact.
Drill out the bolt, starting with a thin drill bit. This is the most important stage. This is where precision comes into play. You should try to make this first hole in the center of the bolt, for example, using some kind of template or device that will hold the drill in the desired position and prevent it from jumping off.
This is how you can solve the problem with a broken bolt. There is nothing impossible about this. Moreover, there are enough methods to choose the most suitable of all in each case.
Since the market for used equipment from Japan and Europe is more developed in Russia, accordingly they bring old junk which needs fixing. It often happens that the bolts on such scooters have never been unscrewed, and they simply stick to the threads. It is very difficult to remove such bolts without breaking the heads or threads (even if you use wd-40). In this article I want to outline several ways to unscrew such bolts, screws with broken threads.
The easiest way (although some consider it a last resort, use the tips below) is drill out the bolt and use a suitable tap to cut a new thread:
1.
We take a drill, a drill suitable for the diameter of the bolt being drilled. Carefully drill it out.
2. Then we buy a set of taps or one tap (but you need to know the exact diameter), select it to match the diameter of the thread.
3. We select and insert the tap into the thread, and begin cutting. For cutting (screwing) use wrench. I used an adjustable wrench.
Don't forget to lubricate the bolts before tightening them. graphite lubricant- in the future this will help you easily unscrew the bolt. To fix the bolts, use a bolt lock (you can buy it at any auto store).
There are still some ways to unscrew a broken bolt.
Method 1: The bolt broke off slightly above the surface of the part. You can try taking an adjustable wrench and catching on this part of the bolt. It is better to spray with WD-40 first.Method 2: if the breakage occurs exactly with the surface of the part, then you need to take a sharp chisel or a flat screwdriver or chisel and hit the left side (edge) of the bolt with a hammer right angle(to give rotational motion). This method is also great for removing stuck flat and Phillips head bolts.
Method 3: again, the bolt broke higher up - take a grinder and cut the bolt in the center. Next, take a flathead screwdriver and remove the bolt.
Method 4: quite a reliable option. We make a mark in the bolt for the drill (in the center), drill to a certain depth (about 15 mm, determine by eye - it doesn’t matter), but not all the way, the diameter of the hole is 15-30% less than the diameter of the nut. We screw in the tap with the left-hand (reverse) thread to the end and as a result you will unscrew the bolt.
Method 5: for welders and those who know how to handle welding. The method works for bolts with a diameter of at least 10-15 mm and the bolt has broken off close to the surface of the part. Here we simply weld a piece of metal to the surface of the bolt and carefully rotate the welded piece counterclockwise (the bolt has the correct thread).
Source: scooter-news.ru
A fastener that is difficult to unscrew (as well as difficult to screw in) (screw or pin) can lead to many troubles, both small and large. The latter can safely include the breakage of a part of a pin or screw in the body of a part, since removing the remainder of the hardware from a threaded hole or socket of a part is a very “delicate” matter that requires great care.
There can be several reasons for breakage of fasteners: exceeding the tightening torque; use of low-grade threaded products; “sticking” of threads of parts and hardware due to corrosion or high-temperature heating, and others.
Breaks of fasteners can be divided into three types: the first - when part of the hardware remaining in the body of the part protrudes above its surface; the second – when the fastener breaks flush with the surface of the part; and, finally, the third - when a pin or screw breaks below the surface of the part. This distinction is made because each of these types of hardware breaks requires its own approach to the issue of extracting residues.
Broken hardware above the surface of the part:
1 – detail;
2 – the rest of the hardware;
3 – crimping pliers
If part of the shaft of a broken screw (stud) protrudes above the surface of the part (for example, one head of hardware has come off), then after first saturating the threads in the socket several times with a special liquid or, in as a last resort, kerosene and after waiting time, you can still try to unscrew the rest of the hardware using appropriate special gripping tools: crimping pliers, pipe wrench, vice, etc. Another technique is to weld a rod-lever to the end of the protruding part and, after impregnating the thread with liquid, try to unscrew the rest of the hardware. Sometimes this can be done, but if not, then you will have to use the following method of removing the remainder of the hardware from a threaded hole or socket - drilling the body of the rod to the thread and picking out the threads of the hardware from the part. You can remove the threads with a stiff wire hook. It is advisable to start the operation from the bottom, where it is easier to make the initial engagement. In addition, the upper turns of the hardware that have not yet been removed will protect the threads of the part from damage by the hook. With minor peculiarities, this method is also applicable in the following two cases of fastener breakage, which are most often encountered in practice.
Breakage of hardware flush with the surface of the part:
1 – detail;
2 – the rest of the hardware;
3 – center punch;
4 – starting drill;
5 – finishing drill;
6 – hook
This is perhaps the most serious case. If possible, you need to file down the end of the fastener so that it becomes even and, having more precisely determined its center, make a deep core here. Then, using a drill equal to the internal diameter of the hardware thread (or slightly less than it), drill a through axial hole in the remainder. It is very difficult to measure the internal diameter of the thread on the hardware itself, therefore, if you have access to the hole, it is better to measure its diameter “in the clear.” When this cannot be done, then you need to use the table below.
Fastener Thread Finish Hole (Drill) Diameter
MZ 2.5
M4 3.3
M5 4.2
M6 5.0
M8 6.7
M10 8.5
M12 10.2
When the diameter of the hardware rod is large enough, it is better to carry out the operation of drilling out its body in several steps, time after time increasing the diameter of the drill until the final one. If the threaded hole is through in the part, then it is advisable to start drilling with reverse side details - the end of the fastener is probably flat, and often it already has center hole, and then the task becomes easier - in this case there is no need to make a core.
Breakage of hardware below the surface of the part and removal of the remainder of the hardware using an extractor:
1 – part;
2 – the rest of the hardware;
3 – bushing;
4 – drill;
5 – extractor
To drill, first of all, as in the previous case, you need to make a deep core exactly along the axis of the fastener. This task is not easy, especially since the end is usually uneven, and it is not possible to file it (make it flat). But there is a way out: you need to select the appropriate bushing from a piece of tube with an outer diameter that matches the diameter of the socket and a drill with a diameter equal to the through hole of the bushing, and drill a guide hole in the piece of hardware. Then use a drill equal to the internal diameter of the thread (or slightly smaller) to drill out this hole. The remains of the rod (the turns of its thread), carefully, so as not to damage the thread of the part, are picked out of its grooves. If the hardware has broken off deeply and there are enough threads of the hole (socket) for the corresponding tap (finishing) to “catch” on them, then the remains can be cut out with it, at the same time calibrating the thread.
In all three cases of broken fasteners, but, most of all, in the second and third cases, a new device is usefully used, called an extractor in foreign reference books (probably from the Latin word extractum - extracted). It is sold in sets of several pieces for hardware with threads of a certain interval (for example MZ - Mb; Mb - M8; M8 - M12, etc.) complete with corresponding drills, and sometimes with bushings. It is hardly advisable to buy a set with extractors for large threads, since it is very difficult to break off such hardware (if only with the help of a lever pipe), rather, the threads on them will break off.
Extractor for removing remnants of fasteners with right-hand threads
The extractor itself resembles a tap in appearance, but without longitudinal grooves. Its working part is conical and has a left-hand screw thread. When screwing the extractor into a hole drilled in the remaining hardware (having a right-hand thread), the latter is turned out. The beginning of the operation is the same as in the second and third cases: punching the center, drilling an axial hole with a diameter corresponding to the extractor, and then working with the extractor.
At the end of the operation, even if the remaining screw or stud is successfully removed, the threaded hole of the part must be calibrated with a thread restorer or a finishing tap.
If the operation to remove the residue was not entirely successful and the thread in the part turned out to be hopelessly damaged, you will have to drill a hole and cut a thread in it with a slightly larger diameter (closest in the row), and use another appropriate hardware for fastening. When such a way out of the situation is unacceptable and a fastener with the same thread is needed to connect the parts, then the following can be done. Having drilled a hole, as in the previous case (only 8–10 millimeters larger), cut a thread in it and screw a fitting into it - a threaded bushing from the previous internal thread and external, corresponding to the hole.
During repairs, sometimes something bad happens - something breaks. Sometimes a broken part leads to trouble with a larger device. For example, a broken bolt in the cylinder block. A broken bolt can cause a lot of trouble. Especially when it breaks down in a place where access is limited.
Simple option
The first thing to do is not to panic. At all. A broken bolt can almost always be removed, the main thing is to do it correctly.
Secondly, inspect the “scene of the incident.” If it breaks when unscrewing it, fill it with WD40, brilliant green or brake fluid - it is required that the broken piece is slid along the threads. You can try annealing the thread blowtorch– you need to look at the circumstances. Let's see where it broke. When a broken piece sticks out above the part, you are very lucky - you can try to unscrew it. If this is possible, screw on two nuts, fixing the lower one with the upper one. We unscrew it by the bottom nut - if the broken bolt left the thread intact, it should come out. There is not enough space for two nuts - we try to unscrew them by the thread with pliers. Another way is to make a slot in the middle with a grinder. As a result, we get a screw that you can try to unscrew with a screwdriver. If it works, the problem is solved. But more often the bolt breaks either flush with the part or inside it.
If it is broken at the part level, try unscrewing it with your finger. In fact, when a broken bolt is inside the hole along the thread, it is clean, and the screw simply broke due to metal fatigue or because it was pulled earlier - it can simply come from a finger. Or we pay attention to the chip - when a piece breaks off, a edge always forms on the fracture plane - we substitute a chisel, a screwdriver - we try to unscrew it with light blows.
Such cases often occur when a non-threaded part is attached with a pin or bolt - for example, a manifold to a cylinder block.
Complex option
If you can't unscrew it using these methods, we'll drill it. The main thing is that the broken bolt is not hardened. There are several methods to try before attempting to drill out a broken bolt. The most basic thing is to take a drill with reverse and a drill bit. Sometimes this trick can be done with a regular metal screw with a drill at the end. We press on the broken part, try to unscrew it with small turns, we need to be careful here - we need to twist it “tightly”. If these methods fail, we move on to serious action. When the diameter of the pin is small, you need to determine how to remove the fragment - there is not enough space for two options.
Method one. Using a small diameter drill, we make two holes in the fragment. Against each other. We drill shallowly - about 5 - 10 mm, preferably away from the center. Then we take a lock ring remover, narrow-nose pliers, or simply insert two nails, clamp them with pliers and try to unscrew them.
Method two. You need a special tool - an extractor. It is sold in tool stores. It's sort of like a cone drill bit, it's reverse threaded, it's very hard hardened metal. First, we select a drill according to its diameter. Carefully mark the center of the stud with a core; we need it to drill the hole. It is not necessary to go deep - just drill a little deeper than the length of the extractor. Then we wrap the extractor and try to unscrew the broken piece.
When no other method helps, the only thing left is difficult option- drill out. To do this you need several sharp drills of different diameters and strong hand. The most important thing is to catch the center of the fragment. We mark the center as accurately as possible with a core; the accuracy of drilling depends on this. Then, using the smallest drill, we drill through the broken one.
It is important to drill exactly along the rest, parallel to the wall, so that the alignment of the holes on both sides is maintained. Then we take the next diameter of the drill and so on until we reach the wall of the hole. If you slightly miss the center of the hole, it happens. The main thing is to stop in time, leaving the thread intact. We take a chisel, screwdriver or nail, and crush the rest of the wall of the fragment inward. Then we simply pull the resulting lump out.
If you, by virtue of your profession or hobby, are engaged in repairing equipment, you are often faced with the question: - how to unscrew a broken bolt, part of which is in your hands, and the other remains in the thread?
In this article we will do short review ways to solve this problem. The choice of method is up to you, since everyone’s skills and available “arsenal” are different. Shall we begin?!
Let's look at how to remove a broken bolt from a thread using an extractor
For those who don’t know, there are external and internal extractors. If the bolt is broken in such a way that it is impossible to “grab” it, then the internal extractor may be the only solution to the problem.
The internal extractor resembles a tap. The shank (non-working part) is made “square” for tools.
Based on the type of working part, extractors are divided into wedge-shaped, rod and screw (spiral).
The working part of the wedge-shaped extractor has the shape of a cone with edges; the cross-section of the rod is the same along the entire length.
The screw extractor is a cone with a thread of left or right rotation.
The operating procedure is as follows:
When starting work directly on the car, make sure that the repair site is accessible for a drill, screwdriver, etc. Well, if the question is how to remove a broken bolt from a wheel hub, the repair area is open. But if you can’t “get to” the part, don’t be lazy and carry out the necessary disassembly, that is, dismantling everything that is unnecessary in this case.
If you don’t know how to unscrew a broken aluminum bolt, using an extractor will be the best solution.
It is better to buy extractors in “extended” sets, i.e. complete with drills and guide bushings for them.
But, unfortunately, such a tool is not always available in this moment or it cannot be used due to the design of a particular unit.
If you have problems with torn edges, we recommend choosing fasteners best quality: https://avselectro-msk.ru/catalog/4976-bolty - bolts of suitable quality that can be purchased in any quantity.
Alternative ways to unscrew a bolt with torn edges
Welding a nut as a way to unscrew a bolt without edges
This old, tried-and-true method has brought many people out of a dead end during repairs.
Specific case. The bolt securing the front suspension arm on an old Suzuki Ignis broke. Moreover, the distance between the eyes of the lever bracket did not allow either hammering or screwing the extractor into the fragment. Welding in this case turns out to be the most effective means unscrew the broken bolt.
The essence of the technique is as follows.
We select a nut of a suitable diameter, put it on the broken bolt and weld it. If the bolt breaks flush with the surface of the part, fix the nut as accurately as possible in the center of the bolt. Let's cook. Carefully, without jerking, unscrew the broken bolt by the nut.
Disconnect the battery terminals! Ensure the safety of wiring, hoses, and plastic products from melting and fire!
Let's say that the extractor and welding are not available to you. Then, if the bolt breaks in the thread, we use
Drilling is an excellent opportunity to tighten a bolt without edges
First of all, let's calculate the diameter of the drill. The formula for standard threads is simple - subtract the thread pitch from the diameter of the bolt (threaded part).
Next important point- how to avoid the drill being pulled to the side? To prevent such a nuisance, there are conductors. A conductor (simplified) is a plate with holes. Guide bushings (sleeves) corresponding to the diameter of the drill are fixed perpendicularly in the holes. The jig is fixed to the part, the sleeves are aligned with the holes with broken bolts. You can drill! It is the sleeve that will prevent the drill from deflecting.
A jig is indispensable if you need to remove a broken bolt from an aluminum part. Especially if it is the engine cylinder head.
You can also combine drilling with knocking out the remains of the broken bolt using a drift.
This technique is used if the threaded holes are through. Starting with a drill of the smallest diameter, we drill out the fragment. When the “wall” has weakened enough, we remove it with a drift. Then we clean the threads with a tap.
In this way, you can, for example, get rid of fragments of the studs securing the exhaust pipe to the exhaust manifold on a VAZ2114-15 without removing the latter from the engine.
Heating to remove a bolt with stripped edges
Let's consider this situation - there are no extractors, welding, conductor and good drills. How to remove a bolt if it is broken?
The problem can be solved (and sometimes very successfully) by heating the parts red-hot. After cooling, they will become more pliable and can easily be unscrewed with a chisel, center punch, etc. The described methods for unscrewing broken bolts are not an exhaustive, universal answer to problems of this kind. For clarity, watch the material in the video.
Thank you for your attention!
