The expression to tighten the screws. How to unscrew the hub nut

04.03.2020

First about the problem in general -

How to tighten a large nut without a suitable wrench?

Sometimes, in order to unscrew a large nut without a suitable key, it is easier to adapt what is at hand for this than to run around the shops in search of a key. I myself use such a not tricky device that grabs and unscrews any pipes and large nuts. At the same time, all that is needed for him is a piece of a profile pipe of 30-40 centimeters and a motorcycle chain. Suitable for bicycles for small sizes. We weld the chain with one end to the pipe, and the other, tightly rounding the nut, we run it inward. We make a hall and the "clamp" is tightened, and the pipe acts as a lever. After the adjustable and gas wrench, this is the first tool, and the cheapest one is no where else.

Well, for a special case -

Interested in the nut for attaching the faucet to the sink in the kitchen.

I can recommend the following.

The best of all-purpose tools for such interesting places is a plumbing wrench with a self-locking moving jaw. He's good at places like this.

You can bend the lips of a thin wrench (there are such in ZIP sets of motorcycles, bicycles and chainsaws) according to the example in such as shown in the photo below -

For a specific size of a nut located in a hard-to-reach place, you can also make such a "grip" from a metal plate 4-5 mm thick. on the handle and with a collar.

Basically, on the clamping nuts of the mixers, the edges are 32.36 or 38 mm. Car enthusiasts may have a hub wrench of this size, it will also work well for this purpose. It looks like the picture below. In the same figure, I highlighted the area of the key, which can be taken as the idea of a homemade key - weld two pins on a suitable tube that will rest against the corners of the nut faces, and make a knob from below.

Among detachable connections, threaded connections take first place both in terms of prevalence and reliability. However, in practice there are many cases when unscrewing a threaded pair is not easy.

The reasons why it is not possible to unscrew the stuck nut (bolt).

There are several reasons why it may be difficult or even impossible to disassemble this simplest connection:

deformation of the thread or connection details, for example, with a strong impact;
twisting not on the thread with the application of significant force - in this case, friction between the surfaces of the parts increases significantly (the effect may be aggravated due to the influence of external factors);
oxidation of the surfaces of the connection parts, the formation of a layer of rust on them;
diffusion of materials between the details of the connection.

The last two reasons are well known to almost everyone, especially motorists.

The problem is that studs, bolts and nuts are most often made of carbon steel. With prolonged contact with water and oxygen in the air (for example, wheel bolts are constantly exposed to this effect), these substances penetrate into the smallest gaps, including between the parts of the threaded connection. As a result, iron oxidizes, forming a layer of rust, which increases friction. It will take a huge effort to move the parts from their place (often the value exceeds the strength of the bolt, and it collapses).

Designers try to avoid such troubles by using parts with protective coatings or made of stainless steels for connections. But that doesn't always work either. If the bolt and nut are exposed to heat (muffler parts are an example), the protective coatings can be broken, corrosion processes are accelerated.

There is also a process of diffusion (mutual penetration) of materials, the parts form a monolith, which becomes difficult to disassemble (this phenomenon is often encountered by those who try to unscrew the bolt on the crankshaft).

How to unscrew a stuck bolt (nut) - the main methods.

To cope with this task, several methods are used. They can be roughly divided into

mechanical;
physical;
chemical.

mechanical methods.

These include methods that allow you to disassemble a threaded connection due to the application of mechanical forces:

the use of box wrenches and socket heads instead of open-end wrenches;
using leverage to increase effort;
impact with a variable direction of force;
accentuated impact (short-term application of significant effort or effort at certain points);
shock destruction of layers of oxides and rust.

An open-end wrench covers only three faces of a nut or bolt head. In addition, there is some gap between it and the edges. In this case, applying enough force to unscrew it can be a problem - the key can break off and “lick off” the edges. A box wrench or socket covers all edges, which allows you to apply more force.

To increase the effort, you can use the lever - increase the length of the handle. At the same time, there is a danger of licking the edges or destroying the fasteners. You can also damage those parts that were connected by a threaded pair.

Often, a change in direction helps to unscrew a stuck or rusted nut - before unscrewing the connection, they try to screw it up. The action of forces alternately in different directions destroys the layers of rust, giving way to the details of the connection.

An example of the application of short-term significant force is given by the method using a chisel and a hammer. A notch is made on the edge, a chisel is pressed into it (directing it in the direction of unscrewing the nut) and hit with a hammer. In this case, the force of impact is much greater than that which can be applied using a wrench. Since the impact is short-term, it cannot destroy the bolt.

For your information! In this way, you can also unscrew the nut with torn edges. This is somewhat easier than trying to file new ones for a smaller key size.

Light tapping of the nut and/or bolt with a hammer will shake the entire structure and destroy the rust layer. It is only necessary to dose the impact force so as not to damage the parts, not to deform the thread. Although, as one of the methods for disassembling a “recalcitrant” connection, destruction of the nut with such blows is suitable. The only problem is that the threaded pair will have to be changed.

Physical methods.

Some of them are based on the physical properties of metals. Of these, only one is widely used - heating the parts of the connection. In this case, the material of the nut expands, the gap between it and the bolt increases, and it becomes easier to unscrew it. If you heat the entire structure, you can destroy the resulting rust, which will also give a positive result. Any source of heat should be used for this purpose - a powerful soldering iron, a building hair dryer, a blowtorch or other sources of open fire.

Important! It is dangerous to use an open flame near wood, combustible plastic or flammable liquids!

A good substitute for an open fire is electric heating. For this, a transformer (factory or home-made) with a secondary winding with a voltage of 1.1 - 1.5 V and a maximum current strength is suitable. Through copper cables and clamps, the secondary winding is closed to a bolt that must be unscrewed. Heating occurs, after which the transformer is turned off, the connection is dismantled.

Other physical methods use the method of wetting surfaces to reduce friction. For example, if fluid is allowed to penetrate into the space between the bolt and nut through the smallest channels, the friction between the threads will decrease and it will become easier to disassemble the pair.

From easily penetrating liquids, you can use those that are always at hand with the motorist:

brake fluid;
antifreeze;
kerosene;
gasoline;
diesel fuel.

The first two contain glycols and ethers - substances with great penetrating power. The rest are aliphatic hydrocarbons and have a similar effect.

The second group also includes such solvents as whitesprit and turpentine. All of them can be used to unscrew the stuck nut. The processes are somewhat different only in time.

The method is simple - wet a rag and put it on the stuck parts. Penetrating into gaps and pores, liquids lubricate surfaces and loosen rust layers. After some time (from half an hour to 3-4 hours), you can try to unwind the connection. If disassembly fails, repeat the process. You can speed it up with periodic light tapping.

These same fluids are the basis for "liquid keys" - special lubricants that are offered in car dealerships.

One of the most popular among motorists is WD-40, which includes mineral oil, white spirit and volatile gasoline. The effectiveness of such a "cocktail" has been tested in practice, it copes with rusted nuts in half an hour.

For your information! If the nut is stuck not due to water ingress, but under the influence of temperatures, the effectiveness of WD-40 is significantly reduced.

Chemical methods.

Their action is based on the chemical destruction of rust formed between the parts of the connection. This requires that active chemicals get into the gaps between the bolt and nut.

Almost any acids are used for such processing of threaded joints:

sulfuric;
salt;
acetic;
lemon;
orthophosphoric, etc.

Sulfuric acid for battery electrolyte or hydrochloric acid for soldering radiators is used in this way:

a rim is organized around the nut or head of the plasticine bolt;
inside the resulting "capacity" make a few drops of acid;
a piece of zinc activates the process, creating a galvanic couple.

A day after the start of such processing, any connection is untwisted.

Weaker acids are less effective, either a significant amount or more time is required.

For your information! Orthophosphoric acid is found in beverages such as Coca-Cola. That is why you can try to unscrew the nut with their help. But its concentration is low, the acid itself has low activity, so such treatment is effective only in "mild" cases.

If nothing helps.

If you still failed to unscrew the nut, the connection can be destroyed - cut off with a grinder.

Another method is to drill out the bolt with a drill.

But before resorting to such methods, you should evaluate all the consequences!

Video.

A nut that is rusty and therefore unwilling to unscrew is a problem that is not uncommon for motorists, locksmiths, plumbers, and cyclists. The part is stuck in place as if tightly. To stir it up, sometimes it takes too much time and effort. We will introduce you to several ways that will tell you how to unscrew a rusty nut quickly and with a minimum of effort.

Why is a rusty nut hard to unscrew?

As a result of the interaction of metal with oxygen in a humid environment, corrosion characteristic of it appears on the material - rust. During its formation, there is a multiple increase in the volume of the oxidation product (the same rust). The nut "swollen" in this way almost tightly merges with the bolt. With a little miscalculation of the forces, you can easily break the bolt, trying to break this alliance.

But rust is far from the only reason a nut won't loosen:

Pollution. If dirt, dust, small metal chips are entangled on the surface of the thread, then this becomes an obstacle to unscrewing the nut and jamming it in one place.
Strong puff. A tightly screwed nut is also the cause of a stalemate. The heavily tightened metal of the surfaces of two parts, a bolt and a nut, sticks to the neighboring one, which leads to the fact that it is very difficult to unscrew the element.
Poor quality tool. The case may be in the same wrench, the edges of which are ground off, deformed or otherwise damaged.

Choosing the Right Tool

To successfully unscrew a rusted nut, you first need to assemble the tools that will help you in this matter:

Throw key.
Socket wrench.
Collared heads.
Mechanical wrench.

Do not try to move a tightly jammed nut with force! Such an impact will only lead to stripping of the thread, cutting off the faceted part, and often even to breakage of the tool. First of all, you need to help the cause with the help of a hex wrench. Open end wrench should not be used.

About safety

Before removing a rusted nut, read these important safety points:

Do not use an instrument that is damaged in any way.
Unscrewing the nut is always carried out counterclockwise.
The tool on the part must be securely fixed.
Use special household gloves to avoid injury.

So, if the nut is rusty, how to unscrew it? We offer you several effective methods.

Method number 1: dissolving rust

How to unscrew a rusted nut? We will not suffer with the tool, wasting our strength in vain. And let's go in search of a substance that will help dissolve rust and reduce friction. Of the most famous, they have proven themselves well:

Special WD-40.
Kerosene.
Brake fluid.
Petrol.
Carburetor cleaner.
Alcohol.
Table vinegar.
"Coca-Cola" and another drink containing inorganic phosphoric acid.

We are sure that at least one of the above was at your fingertips. Further, the algorithm of your actions is simple:

Wet the nut well with the product. Wait about half an hour.
After that, try to carefully unscrew the part with the tool. It didn’t work out - again processing with a substance and wait.
The tool will work better if you soak a rag or napkin in it and wrap it around the nut.
You can then speed up the unscrewing by lightly tapping the part with a hammer.
Another effective way - after exposure to the solution, try to twist the nut with a strong and sharp jerk.
For a small nut, the "rocking" method - back and forth will help.

Method number 2: heating

When the nut is rusted, what will help to unscrew if the previous method is ineffective? Try to heat the part - due to the high temperature, the metal will begin to expand, thereby destroying the layers of rust. The threaded connection from this, in turn, will lose strength.

What can be used as a heater:

Gas burner.
Lighter.
Building hair dryer.
Blowtorch.

In extreme cases, ordinary boiling water will help you. Be careful not to use the heater in close proximity to wood or painted elements.

The instructions for your actions are as follows:

Heat the nut to a high temperature - preferably red hot.
The next step is to try to unscrew it with a key.
If the nut or bolt thread is damaged, it is necessary to weld the end head to the nut, and then heat up the entire structure. Try turning it off with a wrench.

Method number 3: destruction of the nut

Sometimes the question "How to unscrew a rusted nut?" there is only one answer - to destroy it. It will help you in this matter:

Chisel.
Bulgarian.
Hacksaw for metal.
Electric drill.

And here is the algorithm of actions:

Using a chisel and hammer, prepare grooves along the edges of the nut. The further you drive in the chisel, the larger the diameter of the part increases. The result of this will be the destruction of the connection held on the thread. You will achieve a similar effect by drilling such holes with an electric drill. This case is handy if you have enough room to access the nut.
Another way is to use a grinder or a hacksaw for metal. You need to carefully saw the part along the axis of the bolt connected to it.

Method number 4: twisting

The logic is simple: if the nut cannot be unscrewed in the opposite direction, then maybe try to move it along the thread in the other direction? As soon as the part succumbs to your efforts, you need to try to slowly but surely turn it in the necessary direction.

Method number 5: tapping the nut

How to unscrew a rusty nut on a faucet? Any plumber will advise you to tap it.

For these purposes, a small 100-gram hammer will serve as an ideal tool:

Apply light blows alternately on each of the faces. Moving in a circle, go through this path several times.
During your actions, microcracks will form in the rusted metal, which will lead to both deformation and destruction of the corrosion layer.

In no case do not try to hit the jammed nut harder! This will not only not speed up the process, but will also lead to deformation of the edges of the element, bending of the bolt, or even breakage of the part that fastens this design.

Method number 6: wax cup

Rusted nut - how to unscrew? Another way: from plasticine or wax, mold a shape resembling a mini-cup. At the same time, its sides in height should be a few millimeters higher than the edges of the nut. Pour sulfuric acid into the "cup" and put a small particle of zinc. You will cause the effect of the so-called galvanic cell: the acid will destroy rust, and the zinc will help the iron cations to recover. As a result, the nut can be unscrewed without damaging the part with acid.

Problem Prevention

In order not to suffer in the future on how to unscrew a rusted nut on a car, bicycle, mixer, when installing this part, do not forget to do the following:

Be sure to treat the thread with grease: graphite, silicone, teflon.
Refuse to use grease and lithol. The fact is that these substances are perfect only for dynamic, moving parts, but not static ones, which include a bolt with a nut. In our case, such a lubricant will only stiffen and, conversely, will interfere with unscrewing.

We hope that you found a suitable method that helped you deal with the problem. Once again, we draw your attention: do not forget about its prevention!

A stuck nut is a common problem. It is often encountered by motorists, plumbers, cyclists and mechanics. It always takes a lot of time and effort to unscrew a rusted nut.

There are several ways to make this difficult task easier. But before applying various tricks, familiarize yourself with the reasons that lead to the souring of the nut and safety precautions.

Why is a rusty nut hard to unscrew?

Rust is the main culprit for a loose nut. This is one of the types of corrosion that appears on the surface of iron. The reason for such formations is the reaction of the metal with oxygen in a humid environment.

In the process of corrosion formation, a multiple increase in the oxidation product (rust) occurs. As a result, the nut and bolt tightly merge together. Souring of metals can be so strong that when you try to turn the nut, it will be easy to break the bolt.

Another culprit for a loose nut is contamination. Small particles of metal chips and dust remain on the surface of the thread. When the nut is tightened, dirt becomes an additional obstacle. As a result, the threaded surfaces of the bolt and nut are wedged.

The third reason is that the nut is too tight. Some novice locksmiths tighten the nut almost with their feet. A little time passes, the tightly clamped surfaces of the metals stick to each other, aggravating the situation. As a result, a tightly tightened nut cannot be unscrewed.

And the last reason for failed attempts to turn the nut is a poor-quality tool. In the process of long-term use, the edges of the keys are deformed or worn down. It becomes difficult for a damaged tool to grab onto the nut and rip it off the thread.

What is the best tool to use

The right tool will help you unscrew the rusty nut faster and not damage it. To successfully deal with the problem, use a set of tools. The following tools are best suited for unscrewing stuck nuts:

a set of heads with a collar;
mechanical wrench;
socket wrench;
flip keys.

Safety

Do not use a damaged instrument.
Loosen the nut counterclockwise.
Securely fix the tool on the nut.
Wear gloves to avoid injury to your hands.

Dissolving rust

You make great efforts and spend a lot of time to turn the nut, but nothing comes out. Do not get upset and torture yourself in vain. Set the tool aside until it breaks and use a liquid that can dissolve rust deposits and reduce friction.

There are many types of such substances, for example, the most famous remedy is WD-40. Other rust-dissolving fluids exist, such as kerosene, carburetor cleaner, gasoline, and brake fluid. Table vinegar, iodine and alcohol can be no less effective. Some locksmiths have noticed benefits even in Coca-Cola or Fanta, which include inorganic phosphoric acid.

Instruction

Wet the rusted nut well and wait 15-30 minutes. After the allotted time, take the key and try to turn the nut. If it does not work, then the liquid has not penetrated deep enough. Try to wet it again, but already with a napkin or a strip of rag, and then wrap the nut around. So the liquid will last longer on the metal and will be able to better dissolve the rust.
After carrying out such a procedure, the nut will gradually begin to move. You can speed up the unscrewing by tapping with a hammer. Then take the key (if possible, lengthen it, for example, with a piece of pipe), fix it securely on the nut and try to tear it off the thread with a very sharp jerk. If the nut is small, then it is better to unscrew it sideways (back and forth).

Nut heating

If the solvents did not help to unscrew the nut, then you can try to do this by heating. High temperatures cause the metal to expand and rust to break down. As a result, the soured threaded connection loses its strength. Use any heat source such as a heat gun, gas burner, lighter, or blowtorch.

Instruction: Heat the nut and bolt well (preferably red hot). And then try to unscrew it with a ring wrench. In some cases, the nut has damaged edges, so the wrench will not help. To solve this problem, weld a socket head to the nut and heat up the entire structure. Then, using a wrench, unscrew the nut. During heat treatment, be careful not to get burned.

Nut destruction

This method is not the most profitable, but often becomes the only saving method to free the bolt from the rusty nut. To do this, you can use a chisel, a hacksaw for metal, a grinder or an electric drill.

Instruction

Using a chisel and a hammer, start punching grooves on the sides (on the edges of the bolt). Driving the chisel as deep as possible will increase the inner diameter of the nut. As a result, this will lead to the destruction of the threaded connection. Approximately the same can be done with an electric drill, drilling holes in the faces. A broken nut can be easily removed from the bolt. It should be noted right away that these tools are applicable if there is enough space to access the nut.
If there is enough free space, then it is better to use a hacksaw for metal or a grinder. Such tools will quickly help to deal with the problem. All you need to do is carefully cut the nut along the axis of the bolt.

This article looked at the causes of a jammed nut, safety precautions at work, as well as various ways to help solve the problem. Thanks to the tips described, you can quickly unscrew any rusted nut, saving time and effort.

Video: how to unscrew a torn bolt and a stuck nut

Product	Calorie Kcal	Squirrels gr.	Fats gr.	Carbohydrates gr.
Buckwheat porridge crumbly	98,7	3,6	2,2	17,1
Porridge "Amber" (from millet with apples)	138,9	3,8	6,5	17,5
Boyar porridge (from millet with raisins)	221,7	4,8	14,4	19,5
Viscous porridge from millet with pumpkin		4,2		18,5
Gurievskaya porridge	151,2	4,4	5,4	22,6
Pumpkin porridge with semolina	161,5	2,8	8,4	19,9
Brown semolina porridge	162,1	5,3		23,2
Millet porridge with dried plums	121,3	2,4	2,9	22,7
Rice porridge with cocoa	146,2	4,1		20,3
Semolina porridge with cranberry juice	112,7	1,9	4,6
Semolina porridge with carrots	97,3	2,7	5,6	9,7
flour porridge	95,3	3,4	4,9	10,2
Rice porridge with prunes	128,5	1,9	2,4	26,4
Rice with apricots in Hungarian style	119,7	2,6	0,3	28,5
Apple-semolina porridge	128,4	1,9	4,3
Egg porridge (natural)	180,3	10,3		10,8
Egg porridge with vegetables or mushrooms		15,9	13,2	20,9
Barley porridge with potatoes	48,6	1,8		8,7

Responsibility of the moment.

How to tighten nuts and bolts

Lever torque wrench. Simple, cheap, reliable.

Well, the repair is entering the final stage - it's time to start assembling. How are nuts and bolts usually tightened? "From the heart"! One will pull up, and then another foot will rest against something - to "tightly". Another will put a pipe on the key, and insert a crowbar into it ...

In fact, all fasteners are designed to be tightened with a strictly defined force - in technology it is called a moment. Not less than necessary (or it really will unscrew), but not large (you will tear off the thread) ... But where is it - this golden mean? A torque wrench will tell you - it will measure and show you the magnitude of the moment-force. And those keys that are the most modern will also “prompt” aloud when enough is enough.

The oldest torque wrenches are equipped with a round scale and a mechanism similar to a watch. In them, when a bolt or nut is tightened, a thick steel rod is twisted, and very slightly. The gear reducer magnifies this tiny movement many times over, and the pointer on the scale rotates just enough for the mechanic to gauge the force applied to the fastener. This device does not differ in particular accuracy, especially not new: as the mechanism wears out, the gaps in the gears and their axes cause backlash of the arrow, and sometimes jamming.

Later they came up with a simpler tool. A rod of a strictly defined rigidity and length is attached to the base of the square key (for a hexagonal head). And at the other end is a pen with a scale.

This ancient tool has survived over a hundred engine repairs. One of its advantages is compactness.

An arrow is attached to the square. When the mechanic tightens the nut, the rod bends, and the arrow, always fixed relative to the square, shows the force on the scale that has shifted along with the end of the rod. This is a very simple and cheap tool. And if the manufacturer exactly withstood the manufacturing technology, then the most reliable one. From old age, the rod can be deformed - the arrow in the free state will not point to zero. To restore accuracy to the device, bend the arrow - it is made of mild steel.

The most modern, sophisticated torque wrenches are more likely to be used in specialized workshops or on a factory assembly line. They have a scale that vaguely resembles a micrometer scale, and, guided by it, you can very accurately set the required force. When it is reached, there will be a loud click, and the hand will feel a return. So, with this nut finished - it's time to move on to the next one. Such a tool is very convenient if, for example, you need to pull off the crankcase halves - tighten 20-25 bolts with the same force. With less monotonous work, it is tedious to rebuild the device for “your” force for each nut - here it is more convenient to use a simpler tool.

Micrometer scale

With what force to tighten the fasteners - this can be found in the repair instructions. Do not rely on your own experience and do not try to use "someone else's" documentation. Even on motorcycles of similar design, fasteners for identical assemblies should be tightened with different forces (see Table 2). It may differ several times! If suddenly you do not find recommendations, then the nut or bolt is standard, and they must be tightened with a standardized force (see Table 1).

For complex parts tightened with many bolts, the instructions provide a diagram showing the tightening sequence. If it is not observed, it is possible to warp the entire assembly, a leak will form or some shaft will jam. There are several bolts, and the sequence of their fastening is not indicated? So, they need to be tightened crosswise. And gradually, in several steps, until the torque wrench shows the right moment.

General torque specifications for standard fasteners
Turnkey size, mm	Thread diameter, mm	Torque
N*m	N*kg	lb*in
			0,6	4,3
			1,5
			3,0
			5,5
			8,5
			13,0

Modern torque wrench

When reading the tightening torque table, pay attention to the notes. They may contain special assembly conditions. For example, that the threads should be lubricated with oil or thread sealant before tightening ... If there are no additional requirements, then it is understood that the fastener parts must be clean and dry. And preferably neither strongly chilled nor hot - at room temperature.

Cylinder head installation on Chery Very, Chery Bonus

Two dowel pins are located on the top plane of the cylinder block. The cylinder head dowel pins are located on the second and fourth threaded holes on the left side of the cylinder block (when viewed from the front) and are "flexible" dowel pins. The interference between the dowel pins and the cylinder block is 0.053-0.203 mm. The dowel pin and cylinder head are assembled with a transitional fit, with a clearance of 0.016 - 0.084 mm.

Check the cylinder head gasket, which should be smooth and clean, free of burrs and scratches. Install the cylinder head gasket on the flat surface of the cylinder block with the dowel pins so that the part number is on top.

Wipe the contact surface of the combustion chambers of the cylinder head, the upper plane of the cylinder block and the threaded holes. There must be no accumulation of oil at the bottom of the threaded holes of the cylinder block, otherwise this may lead to cracks in the cylinder block.

Install the cylinder head bolt washers on the bolts with the chamfer up and the other smooth surface towards the cylinder head. Next, insert the bolts into the holes in the cylinder head, and then pre-tighten 3/4 turn.