How to unscrew a bolt with broken edges

In some cases, it is impossible to solve an economic or production problem without unscrewing the bolts in certain places. At first glance, this may seem very difficult, but if you know how to do it correctly, in most cases you can easily achieve success. Next, we will consider practice-tested, effective ways to unscrew a bolt with torn edges.

Using a grinder, they make a slot for a screwdriver Source pro-instrymenti.ru

Causes of damaged bolts

Problems with bolts are usually due to the following reasons:

The considered method of attaching parts is considered reliable, but in some cases it does not prevent their displacement under mechanical influences. The result is misalignment or damage to the fasteners.
The mechanic who tightens the bolts sometimes does it too hard. If they are not untwisted for a long time, it may require considerable effort later.
A common cause of boiling bolts is rust. It can fasten parts so that it will be impossible to unscrew.
When working inaccurately, sometimes a larger wrench or other ill-suited tool is used. This can lead to the edges of the bolt licking off.
When connecting for a long time, diffusion phenomenon may occur. In this case, metal atoms gradually penetrate into adjacent parts of the fastener. This attachment develops slowly, but within a few years it becomes strong.

For these and other similar reasons, connections arise that cannot be processed immediately. In such situations, you need to know how to unscrew a bolt with a broken head.

Drilling a bolt using a drill Source sdelai-lestnicu.ru

Features and Benefits

An internal hex bolt differs little from ordinary bolts in appearance, but, nevertheless, their minor design feature makes them more durable, reliable and convenient.

Advantages of hexagon socket bolts:

To tighten the screw, there is no need for free space around the hardware because the key used to tighten the fastener is inserted directly into the head, rather than overlapping it.
The slot on the head is not so easy to lick off; it is more durable compared to the slot of a regular bolt, since the material of the hardware is denser than the material of the key, and the key is more likely to deteriorate than the fastener slot.
A hexagon socket wrench is cheaper than an open-end or socket wrench.
The head of the fastener does not have sharp outer edges.
Bolts with an internal hexagon are used in hard-to-reach places, and after screwing in, the head does not remain on the surface, but sinks flush.

Countersunk screw

Galvanized hex bolt hardware can be used in wet conditions because they are more resistant to corrosion.
Hardware of this type can be dismantled and used again, just like the structure itself assembled with their help. Bolts can be used in combination with a nut: in this case, they are inserted into the hole, and the nut is screwed on the other side; or without a nut, then they are screwed into a threaded hole.

Preparing for extraction

Before unscrewing a bolt with torn edges, it is necessary to carry out preliminary preparation. The following methods can be used here:

There are special liquids that easily penetrate cracks in metal and allow you to remove rust. An example of such a product is WD-40. It contains mineral oil, as well as white spirit and gasoline, which belongs to the light fractions. This treatment significantly reduces friction, allowing the bolt to be easily removed. Before unscrewing the stripped bolt, it is also possible to use kerosene. Brake fluid is used in the same way.
Lightly tapping with a hammer can reduce the bolt's grip. In this case, you need to make sure that the blows are not too strong. Otherwise, the risk of damage to the object increases.
Sometimes warming up helps. This can be done using any available means that provide heat. One of the popular tools in this situation is a gas torch. Heat treatment will help remove contaminants and remove rust, reducing the adhesion of the part.

It is convenient when there is sufficient space in the immediate vicinity of the problem screw so that the appropriate tools can be used.

Bolt with damaged edges Source sdelai-lestnicu.ru

How to remove a bolt if it is broken and nothing helps or the thread is already badly damaged

In such a difficult situation, you should drill a hole so that its width is sufficient for cutting new turns. Although the hardware may be hardened and difficult to give in. Then it must be subjected to heat - heated red-hot - and then left to cool. It is strictly forbidden to forcibly cool it with water - too sharp a temperature rise will only lead to the appearance of cracks.

The operation of slowly changing the temperature regime must be carried out several times. Due to this, the metal will be tempered and slightly softened, and the damaged element will become easier to drill out. But if the body of the part (unit, functional unit) is made of aluminum, special care should be taken to ensure that the surface in the heating zone does not warp.

Extraction procedure

When a master sees a rusted screw with damaged edges, he must begin work with pre-treatment. With its help, it will remove dirt, rust, and reduce the durability of the bolt. Next, you need to directly proceed to the procedure of how to unscrew a bolt with a broken thread.

If the edges of the bolt head are smooth, removing it will require a strong grip on the tool being used. This is ensured by using a gas key. It can even unscrew fasteners with no edges, almost completely. It is important to consider that the handle is of sufficient length so that the procedure requires moderate effort.

Damaged bolt Source intehstroy-spb.ru

Good grip can be achieved by using spanner wrenches. It should be borne in mind that its strength depends on the exact selection of the size of the tool. If the fastener uses a washer, then in some cases you can make it easier to unscrew by breaking it with a hammer and chisel.

Using these tools helps most of the time, but not always. If it was not successful, then other methods will need to be applied.

A set of tools that may be useful for unscrewing bolts Source sdelaysam-svoimirukami.ru

How to unscrew a broken bolt using a drill with a left-hand spiral

In two stages:

Then arm yourself with the one that rotates counterclockwise (let it be a little larger in diameter) and, using it, gradually remove the body.

You should be careful and control the direction of movement - then the edges of the working rod will catch the remaining hardware, pushing them upward, but without destroying the thread. If any damage occurs, it will be so minor that you can easily fix it with a tap. This method is effective when the fastening joint is not yet very rusty or stuck.

Using destructive methods

The methods outlined below are united by the fact that when they are used, the bolt is destroyed. However, if other options do not lead to success, then you need to use them.

If you saw off the bolt head with a grinder or remove it with a hammer and chisel, you will be left with a threaded part embedded in the part being fastened. It is necessary to make a longitudinal notch on it, using which you can use a screwdriver.

Sometimes the remaining part of the bolt does not respond to such attempts. In this case, you can unscrew a bolt with torn edges by trying to turn a screwdriver, while helping yourself with blows of a hammer.

If the edges are torn off so much that it is completely impossible to use them, then the following methods can be used:

A deep cut with vertical walls is made on the bolt head. Then you can use a screwdriver to unscrew it.
Sometimes a hammer and chisel are used to turn a bolt; in this case, you need to use the following method on how to unscrew a torn hex bolt. The blows are applied slightly obliquely and are done in such a way that the bolt gradually twists around its axis.
A TORX sprocket can be used. A slot is driven into the head until a hole that exactly fits the shape is obtained. After this, twisting is done.
You can use a special part - an extractor. To do this, use a drill to drill the bolt along the longitudinal direction. Insert it into the resulting hole and remove the fasteners.
A drill with reverse may help. Its peculiarity is rotation in the direction corresponding to the unscrewing of the screw. To do the job, drill a thin hole, then use a tool to turn it so as to remove the screw.

One of the effective ways to remove a bolt is to additionally sharpen the head. It is again made hexagonal, but now its size will be smaller than the previous one. Next, select the desired wrench and disconnect. The edges are processed using a file.

By watching the video you can learn more about how to unscrew a broken bolt:

Recommendations for working with screw heads and self-tapping screws

While performing the above work, in order to get the expected result and avoid injury, you must adhere to the following rules:

Before attempting to unscrew the screw, you need to inspect the back side of the workpiece. If its end peeks out of it, then you can try to unscrew it from this side, and when the head is free, grab it with pliers;
you need to decide whether the thread on the fastener is right-handed or left-handed in order to unscrew the screw or self-tapping screw in the correct direction;
after the screw has been unscrewed, you can ensure reliable fastening in this place using a larger self-tapping screw or you can use a bolt with a nut;
When using the described methods, nicks and chips are formed, so in order to avoid injury, you must work with protective glasses and gloves.

There are no lose-lose situations. If there is a problem with unscrewing a screw, screw or self-tapping screw, you need to assess the situation, choose one of the described methods, and then use it to remove the fastener.

Video description

How to unscrew a bolt with torn edges of the door lock of an Audi A6 C5.
Some people in this situation weld a new head to the bolt. This method is convenient, but its use requires the ability to work with a welding machine, which is not suitable in all cases.

The spanners must match the size of the bolt Source sdelaysam-svoimirukami.ru

Adviсe

Sometimes difficulties when unscrewing arise only at the beginning. If you manage to turn the fastener, you can often use a regular screwdriver.

Sometimes, in order to successfully unscrew a hex with broken edges, you need to increase the friction between the wrench and the part. Having rubber can help in this situation. They wrap it around the head of the bolt and use a gas wrench. As a result, when scrolling, the use of this material increases friction, helping to solve the problem.

Choosing the right tool will ensure the connection is working properly Source sdelaysam-svoimirukami.ru

Sometimes it is advantageous to use “cold welding” to attach a nut with high-quality edges to a bolt. We are talking about a special glue that provides reliable adhesion. After this, use a wrench to unscrew it. This option can be effectively applied to almost any bolts, even those that cannot be removed by other means.

It makes sense to pay attention to the use of an extractor. It is a drill with a small head at the tip. It is used to drill damaged hardware lengthwise. Its feature is the use of threads in the opposite direction than the screw. When creating a hole, wedging occurs, and at some point this process begins to slow down. After this, the extractor rotates along with the bolt, which makes it possible to unscrew it.

A key spanning six edges ensures a strong grip. Source sdelaysam-svoimirukami.ru

Rusted nut

Another problem that is familiar to car enthusiasts (and not only) is a rusted nut and/or thread. In this case, you should not make heroic efforts to unscrew the fasteners. Your edges will simply “stick together” and another problem will be added to the boiling thread. If after a couple of attempts you can’t unscrew it, try the following methods one by one:

Tap the bolt with a wrench. There is a chance that the rust will crack and the nut will be unscrewed.
Fill the connection with kerosene and wait. It will eat away the rust, after which it will be easier to unscrew the rusted nut. But during this operation you cannot smoke, turn on welding, or be near an open flame.
Warm up the nut. The metal will expand, making it possible to unscrew it. The trick is to get the nut to heat up while the bolt shank stays cold, so heating up must be fast. To do this, use a hair dryer or an open fire (be careful with this). If the screw is small, you can take a powerful soldering iron, heat it to maximum temperature, then quickly heat the joint.

This method will (almost) destroy the nut, so it should only be used in hopeless situations. Grooves are made on the edges (using a metal saw, grinder, or file). A flat screwdriver is pressed into this groove, giving it a direction in the direction of unscrewing. The handle is hit with a hammer. If there is at least a couple of movements, it may be possible to unscrew it.

Use a special puller (pictured above). Using a bolt, the pin rests on one of the faces, after which you can try to move it from its place. Due to the fact that the lever can be attached, it can work even in very difficult situations.

You can also fight rust with lubricant. Try filling the joint with fluid universal lubricant (available in WD40 cans). After waiting a couple of hours, we try to work with the key. If it doesn’t work, we try other methods one by one.

Preventive measures

If the bolt's edges are damaged, then to unscrew it, you can use the methods outlined in the text. However, it is important to prevent fastener damage or at least reduce its likelihood. To do this, you need to pay attention to the following:

You need to buy high-quality and reliable hardware. It is advisable to first verify its suitability.
When tightening, you must use a tool that is exactly the right size. It should not slip and damage the edges of the head.
You should only use the right tool. If the edges of the wrench are damaged, it will cause the formation of poor-quality fasteners.

Tightening the bolts carefully will help reduce the likelihood of it sticking.

Sometimes warming up the fasteners helps Source sdelaysam-svoimirukami.ru