How to use a torque wrench for a car is a question that interests many vehicle owners. Although a man should never complain about his car - he chose it himself, but what to do if the car gives more and more reasons for revelations to neighbors in the garage? Bad roads and low-quality fuel do their dirty work, putting the iron horse out of action over and over again. You can look for repairs on the side; nowadays there are countless different service stations that guarantee complete relief from malfunctions.
- Torsion wrench with fixed pointer
- How to use a torque wrench to avoid stripping threads! Video:
- Metric Bolt Torque Chart
There are times when you don’t want to part with your luxury; there is a lack of trust in other masters - and this is understandable. If the owner of the car treats it with care, then the repairs are done at home.
Who else but him should know all the features of the vehicle? Then we are faced with a fanatical car enthusiast who has an impressive set of tools in his garage, among which there is always a torque wrench for the car.
What kind of instrument is this?
Such a device is necessary for tightening connections that require a uniform, measured application of force. There is a lot of debate about its necessity. But it is obvious that this tool is indispensable for clear indicators of the pressure force on a bolt or nut. The key can also be used in other areas: assembly of machine guns, industrial equipment, shipbuilding.
In essence, this is a regular wrench, only equipped with a built-in dynamometer. This makes it possible to tighten fasteners with a precisely specified force.
That is, if, for example, the instruction manual for your car states that the nuts should be fixed with a force of one hundred and ten newtons, then you can accurately ensure such indicators only with the help of a torque mechanism.
Particularly important will be the ability to set a given parameter. It is the accuracy of tightening the various connections of the mechanism that is the advantage of this device. Manufacturers produce many types of such instruments.
They consist mainly of parts similar to all models:
- handles for attaching the nozzle, which is tightened;
- an attachment clamp having positions in positions one to three;
- removable attachment made in the form of a ratchet;
- a spring mechanism having a measuring scale;
- a handle equipped with a lock that regulates the specified force.
How to use a torque wrench scale. Video:
Step-by-step operating instructions for tightening the cylinder head
To perform this important operation, when assembling the cylinder block and head, you need to select the type of tool and prepare: a special torque wrench, a ratchet, a socket head, and some motor oil (clean).
It is recommended to adhere to the following order:
- Study the repair and operation manual for this car and determine in what order and with what force (torque) the cylinder head should be tightened;
- Lubricate the mounting bolts with engine oil;
- Insert the bolts into the technological holes and tighten them by hand;
- Set the maximum force level on the dynamometer in accordance with the vehicle repair manual;
- During the first approach, tighten the bolts of the threaded connection, from the middle and further according to the diagram, without bringing the force to the maximum;
- At the final stage, each bolt must be tightened “until it clicks” with a torque wrench. A good example can be seen in the video.
Video: “Tightening the cylinder head with a torque wrench”
Types of Torque Wrenches
Such devices differ in their design features and mechanisms of action.
Torsion wrench with fixed pointer
A special feature of the design of a pointer torque wrench is the presence of a fixed pointer and a solid rod with a scale on both sides, graduated in Newtons per meter. During actions aimed at clamping a bolt or nut, the scale tilts relative to the fixed pointer at an angle that is proportional to the applied force.
These deviations are used to determine the magnitude of the force. Its use has a great advantage over other tools - it can be used on bolts and nuts with right- and left-hand threads.
The only negative is the high error, reaching 15%. This nuance is corrected in a similar way to the pressure indicator, where the deflection angle is adjusted using a dynamometer in the form of a spring.
Snap key
It is the most popular among car enthusiasts and professionals. This tool has a ratchet, which is essentially a gear mechanism with a click element.
How does this type of torque wrench work? When the indicator reaches the set value during operation, it stops performing the task and slips, making characteristic, recognizable clicks.
After setting the desired force value, you can begin tightening the nut without controlling the force. Inside the head there is a gear, which is stopped by a locking mechanism.
The operating principle is to limit the effort. A rod is installed in the rotating part of the handle, which holds the locking mechanism when the set value is reached. It is impossible to apply force above the specified parameter. The tightening torque is measured discretely. The first click will signal the completion of work with the element. The torque will not exceed the required value due to the adjustable limiter.
This type of torque wrench requires careful handling, and the only drawback is the ability to work with it only with a clamp. This is the most common tool. Ratcheting sounds can be heard from most service stations and private garages.
Device with electronic mechanism
The digital torque wrench stands out for its reliability. The error reaches 1%, which is unusually small, but often such accuracy is not necessary. It has a built-in small LCD indicator for measuring torque. You can also select computational units.
It is possible to set a limit value, when reached, an audible signal is emitted.
This is very convenient when using the key in a confined space, when it is not possible to visually control the clamp. The high price of an electronic torque wrench is its main disadvantage.
All types of such tools are great for use when repairing a car. The choice is based solely on the owner’s experience, financial capabilities and desire to learn. No matter how much conservatives talk about the uselessness of this type of device for a car enthusiast, in fact this key is needed.
It is universal as it has interchangeable heads that make it suitable for any diameter. Its use by inexperienced craftsmen is especially successful. This helps avoid stripped bolts, broken studs, stripped threads, or broken nuts.
Without an open-end torque wrench, it is impossible to achieve uniform tightening of the many threaded elements on the cylinder block or even on the wheel. But this is a mandatory condition for the operation of the mechanisms.
Types of power switches
It is up to you to decide which type of tool is best to choose. It all depends on what material resources you have, as well as for what purposes such a device is needed. are presented in our car market in the following modifications:
- arrow options;
- limit type, or click;
- equipment with digital indicator.
The first option - arrow keys - is quite common among domestic car owners. They are inexpensive, but their error is quite high - from 6 to 20% in some cases. Only professional models that look like a pressure gauge will show less error in operation. Basically, pointer specimens are used in work where high accuracy is not required, if you just need to tighten the thread.
Snap force wrenches are semi-professional tools. They are used by car mechanics at service stations, as well as by experienced drivers. Such instruments have a fairly low percentage of error; most of them are calibrated at the manufacturer, for which a certificate is issued.
Force-measuring wrenches with a digital indicator are the most accurate and reliable, but also the most expensive of the existing options. The error percentage of such a tool is less than 1 percent. It is also possible to download data into Excel and install programs from . These torque wrenches are mainly used by professional service stations.
If you don’t yet know which tool to choose for your car, then, of course, give preference to the last option. But be that as it may, any driver or car owner should have at least an arrow key in their arsenal.
Torque Wrench Selection
The goals you pursue form the basis of the requirements for such tools. The financial aspect is also important. The most expensive will be a key with electronic filling, but if your goal is not to achieve high accuracy, then you can take a closer look at click or torsion models.
When deciding which torque wrench to choose, be sure to ensure the originality and integrity of the tool. There should be no visible defects on it. Choose models made of durable alloys and reliable mechanisms, then the key will last much longer. The choice of the range of expected efforts will be important. The instructions for the car will help you determine this, where the permissible parameter for the applied clamping forces is indicated for each threaded connection.
In short, base your purchase on what you will do with it. Before testing a torque wrench at home, you should test it in a store.
Don't forget to make sure how it fits in your hand. Comfort of use is very important, because you not only need to keep the instrument intact, but also not damage your palms.
The handle should fit your fingers perfectly. The surface must be selected from non-slip materials so that the hand does not jump off the key at the most inopportune moment. Also, you should not feel any strain on your wrist with prolonged use. And now when all the details are taken into account, you can start purchasing.
How to use a torque wrench to avoid stripping threads! Video:
Operating principle and device
It is necessary to understand the principle of operation of a torque wrench, because without this you will not be able to properly use the capabilities of this tool.
The device resembles a regular ratchet. But the key difference here is the presence of a special scale. It displays the force that the user applies to the fastener.
The tool is based on a handle that can rotate in two directions. The main scale is applied to the body, and there is an additional one on the handle. The main scale is intended to demonstrate the range of forces relevant to each specific torque wrench.
In reality, it is not difficult to understand how a special torque wrench for a car works. Although they come in different types, the devices are designed approximately the same. The design of a torque wrench depends on its type. Let’s look more specifically at the features of working with pointer, click and electronic devices.
Many motorists who work on their cars independently know what a torque wrench is for. It allows you to apply the required force with maximum precision when tightening threaded connections. That's what a torque wrench is for. This is a device for tightening nuts and bolts with a given and measured force. It is important to know how it is measured. Then it will be easier to understand how to correctly calculate the tightening and pre-set the tool. This force is measured in Newton meters (Nm).
Craftsmen working at service stations can hardly imagine a set of tools for servicing customer cars that does not include a torque wrench. With its help, precise force is measured. These measurements help prevent leaks, depressurization, and breakdown of vehicle components and mechanisms.
The keys have different attachments that are adapted to perform certain tasks. Therefore, it is a universal device with wide functionality. To use one or another attachment, an output square is used. The user mounts a horn-type, union-type or nut-type attachment on it. Don’t forget about screwdriver wrenches, which are useful when working with electronics and very fragile car mechanisms.
The differences between keys of different types are minor. All of them must include in their design:
- handle;
- clamp for setting the torque;
- measuring component or setting scale;
- removable attachment (ratchet);
- socket for nozzles;
- housing with a spring mechanism.
Before purchasing a torque wrench, be sure to consider what specific tasks it will be used for. The main role is played by the size of the fasteners and their location. For hard-to-reach places, it is more convenient to use click and horn devices. And the tool with maximum precision is an electronic type of torque wrench. Although such devices are mainly used in car repair shops, they are not really needed for personal use.
How to use a click key?
In principle, the use of such a tool is slightly different from the use of other types of products. But there are still nuances that require careful consideration. Intuitively, one can understand that it is necessary to use such a tool in situations that require a certain level of effort.
For the most part, they allow you to tighten elements clockwise, but there are also tools in the opposite direction. Reversible models combine both qualities.
When purchasing a tool in a store, the kit comes with detailed instructions on how to use a click-type torque wrench. This is necessary not only to accurately complete the assigned tasks, but also to extend the service life of the tool.
A very important point is that the lever arm cannot be extended with a pipe or other homemade device. Otherwise, the accuracy drops significantly.
You will have to work only with your own hands. Using a torque wrench as a regular wrench will significantly increase its wear.
The approach to working with one or another tool depends on the type. The click limit key first requires setting the desired value of newton meters.
To do this, you need to carry out the following manipulations:
- Loosen the nut responsible for the “stop”.
- Fix the required load on the scale using the handle.
- Insert the lock nut into a stable position.
Rough force values are marked on the stationary part of the handle, and precise values on the rotary part. By combining them, it is possible to achieve the desired result. After this you can start working. When the desired result is achieved, a characteristic sound will be heard in the form of a click - the threaded connection is clamped.
When using such products, you can not pay attention to the angle of the head relative to the bolt or nut. The forces will be evenly distributed over the surface of the part without compromising accuracy. And thanks to the sound signal, you can work with such a key almost blindly. But with all this, you must strictly follow the factory instructions.
Working with an electronic key requires a more scrupulous attitude. The main advantage is the ability to regulate the force within tenths or even hundredths of a newton meter.
Contact with the screwing element must be at right angles. The buzzer will prevent you from overdoing it.
It's quite simple. However, in order for the device to last a long time, you must not only know how to use a torque wrench correctly, but also how to care for it.
It consists of the following points:
- Operate the tool only within critical ranges to avoid premature wear.
- Periodically carry out testing or verification so that the indicators do not deviate from the numbers indicated on the scale.
- Do not exceed the indicators set on the device, because it may simply break down.
- Inspect regularly after use for mechanical or physical damage to the housing or moving parts.
- Store the tool exclusively in dry places.
- To save money, leave the device only with the regulator set to zero.
Metric Bolt Torque Chart
The force is indicated in Newton meters.
Metric Torque Wrench Torque Chart and Instructions
| Thread diameter (nominal) | Bolt or nut head size (on a wrench), mm | Metric thread pitch | Strength classes in accordance with GOST 1759-70 | ||||
| Bolted connection | |||||||
| 5.80 | 6.80 | 8.80 | 10.90 | 12.90 | |||
| screw | |||||||
| 4,0;5,0;6,0 | 5,0;6,0 | 6,0;8,0 | 8,0;10,0 | 10,0;12,0 | |||
| 6 | 10 | 1 | 0,5 | 0,8 | 1,0 | 1,25 | 1,6 |
| 8 | 12 — 14 | 1,25 | 1,6 | 1,8 | 2,5 | 3,6 | 4,0 |
| 10 | 14 — 17 | 1,25 | 3,2 | 3,6 | 5,6 | 7,0 | 9,0 |
| 12 | 17 — 19 | 1,25 | 5,6 | 6,2 | 10,0 | 12,5 | 16,0 |
| 14 | 19 — 22 | 1.5 | 8,0 | 10,0 | 16,0 | 20,0 | 25,0 |
| 16 | 22 — 24 | 1,5 | 11,0 | 14,0 | 22,0 | 32,0 | 36,0 |
| 18 | 24 — 27 | 1,5 | 16,0 | 20,0 | 32,0 | 44,0 | 50,0 |
| 20 | 27 — 30 | 1,5 | 22,0 | 28,0 | 50,0 | 62,0 | 70,0 |
| 22 | 30 — 32 | 1,5 | 28,0 | 36,0 | 62,0 | 80,0 | 90,0 |
| 24 | 32 — 36 | 1,5 | 36,0 | 44,0 | 80,0 | 100,0 | — |
Instructions for using torque wrenches from various manufacturers
The instructions presented are suitable for similar models from other manufacturers:
| Company name | Model | Instructions |
| Master | 1/2″, 70-350 Nm Model 012-40210С | View instructions |
| King Tony | 1/4″, 3/8″, 5-25 Nm Model 34423-1A Model 34423-2A | View instructions |
| Jonnesway | Т04060 1/4″DR, 5 – 25 Nm Т04060A 3/8″DR, 5 – 25 Nm Т04061 3/8″DR, 10 – 60 Nm Т04080 3/8″DR, 20 – 110 Nm Т04150 1/2″DR , 40 - 210 Nm T04250 1/2″DR, 50 - 350 Nm T04300 3/4″DR, 80-400 Nm T04500 3/4″DR, 100-700 Nm T04700 3/4″DR, 100-1000 Nm | View instructions |
Recommended companies for purchasing tools:
In addition to the above manufacturers, for which instructions are provided, it is recommended to purchase the following companies: BERGER, Force, Delo Tekhniki, Zubr, Matrix, Avtodelo, JTC, Ermak, Arsenal.
The best key models
Strength wrenches from the German company Hazet are recognized as one of the best on the world market. They are produced for industry and car service, but just amateurs can purchase such a serious tool, because Hazet always means durability, excellent product quality and accuracy of all indicators.
The German company Hazet produces various models of types and sizes of force wrenches with excellent characteristics. The best torque wrench from this brand was chosen in 2005, and it was the 6000 series tool, which received a special award for innovation and best design. Also, the ½-inch click-type device, which has a wide measurement range, has long been loved by car owners. An electronic type wrench, which has a wide range of tightening torques, is considered very modern and progressive.
Owners and construction equipment will benefit from powerful 3/4-1 inch torque wrenches. To unscrew heavy nuts, you can purchase special multipliers that will increase the torque. If you need to check your dynamometer equipment, there are special Hazet electronic devices.
Also, do not ignore the products of KABO TOOL COMPANY. This is one of the world's leading manufacturers of professional tools that comply with ISO 9001 quality standards. Only the best chrome vanadium and chrome molybdenum steels are used in the production of KABO tools, as evidenced by the worldwide popularity of the brand.
Because we have never encountered such a tool. Why are such devices needed? In what types of work are they used? Let's try to answer the questions presented.
Criteria for selecting a device
The correct choice of tools determines the quality of the work performed, the durability and stability of the mechanisms being serviced. First of all, you should decide on the size of the key. The specifics of the work performed may require the participation of one or more types, allowing the use of nozzles of different sizes.
Attention! When choosing a key, you should not strive to purchase universal models with a large range. The higher the versatility, the higher the instrument's error. It is better to purchase several wrenches with a smaller range; they will ensure high measurement accuracy.
In addition, operating conditions and the configuration of the mechanisms being serviced should be taken into account. These factors determine the desired key indication mechanism. If work is carried out in conditions of insufficient lighting, poor visibility, or among many structural elements that hide the tool and make it difficult to visually control the force, then a limit-type click wrench will be the optimal choice. If it is necessary to work with constantly changing tightening parameters, you should pay attention to pointer devices that demonstrate the amount of force at a given time. To obtain high accuracy, electronic devices are used, although they are the most expensive.
An equally important point will be the choice of the key manufacturer. Experts disagree, since the specifics of the work and the requirements for the accuracy of the tool are different for everyone. Some believe that only products from Germany or another European country should be used. Others quite reasonably recommend Taiwanese or Chinese samples. When choosing a manufacturer, you should compare the technical characteristics of the tool, its price and your own needs and capabilities. The optimal choice will be the device that most harmoniously combines capabilities and needs.
