How to read a torque wrench – How to Read a Torque Wrench

How to Read a Torque Wrench

One of the necessary tools for the home auto mechanic is a torque
wrench. If you want to follow all the manufacturer’s recommendations
for repairs and routine service, you will need to know how tight to
tighten bolts. The torque wrench will tell you exactly how tight
something is and allows you to set the wrench so that you don’t
over-tighten a bolt or nut.Difficulty:Moderately EasyInstructions
Examine the torque wrench. You will see that the torque wrench looks
very much like a standard socket wrench except that the bottom part of
the handle has a dial that you can rotate to set the degree of force
you want to exert on a bolt or nut as you tighten it. By rotating this
dial, you can chang


Using a metric or newton meter torque wrench requires a bit of math if
you’re trying to tighten a nut to a certain number of pound-feet.
You’ll have to do the conversion from English measurements (feet,
inches and pounds) to metric units (meters, centimeters and kilograms
or newton meters). Then you’ll use the metric measurement as you turn
the wrench or, if you’re using a click-style torque wrench, set the
target torque. A newton meter, like a pound-foot, is a measurement of
force — the word «meter» here refers to the unit of length, not to a
dial with numbers on it like a water meter. A newton meter is a little
less than 1.5 pound-feet.Difficulty:Moderately EasyInstructions
Things You’


When a torque wrench isn’t available you need another way to determine
how much torque is applied to a bolt or nut. To do this you can use a
load indicating fastener. These are bolts or other types of fasteners
that function exactly as a standard fastener but include a gauge or
indicator. This indicator is used to determine when you’ve applied the
proper amount of tension to a bolt.Difficulty:Moderately
EasyInstructions Things You’ll Need
Load indicating
Socket wrench
class=»error»>Determine the size of bolt that you need to torque and
find the same size of load indicating bolt. Measure the width of the
bolt with a ruler if the size is unknown.

Hobbies, Games & Toys

A torque wrench is a tool that is used to tighten bolts and nuts.
Torque wrenches are different from other wrenches in that they have a
torque setting dial on the handle. This allows the user to tighten a
bolt only to the manufacture’s recommended torque, thus eliminating
over tightening. Torque wrenches are available in both a beam variety
and a clicker variety. Setting the proper torque on a clicker torque
wrench takes only a few seconds to
accomplish.Difficulty:EasyInstructions Determine what torque
setting you need to use by referring to the manufacture’s instructions
for the bolts or nuts that you are installing.
Hold the body of the
clicker torque wrench in one hand and place you

Home & Garden

You have probably seen a torque wrench in an automotive garage where
mechanics use them to set torque settings on engines, and secure the
lug nuts to the wheels. These tools are handy to have around, because
you always know that the fastener you’re using is solid and to
specifications. Dial and digital style torque wrenches are easy to
read because you only have to read a number. But the system on the
side of a 3/8-inch ratcheting torque wrench seems like a code that’s
difficult to break. Once you know the trick though, reading the
numbers comes quickly.Difficulty:EasyInstructions Locate the handle
on the bottom of the 3/8-inch ratcheting torque wrench. Look for the
numbers running around

Home & Garden

Although they appear to be rugged and sturdy, torque wrenches are
actually very precise measuring instruments. They are designed for one
purpose and one purpose only: to impart a precise amount of rotational
torque to a nut or bolt per the manufacturer’s specifications.
/>But because torque wrenches are so sturdy and well-made, many people
think that they can be used for other applications as well. Although
they have the capacity to function as a different tool than what they
were designed for, any usage other than design applications should
never be undertaken. Never Use as a RatchetAlthough a torque wrench
looks and acts like a ratchet handle, it should never be


A torque wrench is a type of wrench that allows you to tighten a nut
or bolt with a specific amount of force. Many applications require you
to tighten a nut or bolt with enough force to keep it securely
fastened but not so much force that a part is damaged. A micrometer
torque wrench uses a rotating handle to specify the torque you wish to
use. This operation is similar to the way that a micrometer is
adjusted to measure distance.Difficulty:ModerateInstructions Things
You’ll Need
Micrometer torque wrench

the scale on the shaft of the micrometer torque wrench. This scale
indicates the first digits of the torque setting. For example, this
scale might show


How To Use a Torque Wrench

While many automotive fasteners on your vehicle do not require accurate torquing, the critical components certainly do, such as suspension, engine, and drivetrain components. If you do not use a torque wrench, you probably are not getting those bolts tight enough, or in some cases, too tight. Both of which are really not good. Knowing how to use a torque wrench correctly is an important step in critical component assembly work.

The torque wrench was invented in 1918, interestingly to prevent underground water pipes from being overtightened. The original version was a beam-style wrench, which uses a pointer on scale to indicate torque application. Beam wrenches are accurate when taken care of and are still sold today, though they are more rudimentary than modern torque wrenches.

The beam style torque wrench is useful, but it does not tell you when you have reached your target. The best use for these wrenches in is measuring rotational force, such as when setting up a rear differential.


Small inch-pound wrenches like this are usually 1/4″ drive, so you need an adapter to go to 1/2″ for big stuff like pinion nuts.

Torque Wrench Types

There are several types of torque wrench, including deflecting beam, slipper, click, hydraulic, electronic, and mechatronic wrenches. The most commonly used versions in automotive applications are the click and electronic, so we will focus on these.

The most common style of torque wrench are the mechanical clicker, and the electronic wrench. they both have advantages and disadvantages.

Click style wrenches are what most of you will be familiar with. When you reach the desired torque rating, the internal mechanism clicks, letting you know that you have reached it. This is done with a precision calibrated clutch made from a ball and spring where the ball rests in a detent and when the torque head reaches a level that overcomes the spring, the ball pops out, making a “click”. The torque application does not stop, so you can over-torque if you don’t stop when you hear the click. These wrenches are set with a rotary ring on the handle. These wrenches are very affordable and when not abused, will remain accurate for many years. Most click style wrenches are noted in ft/lbs, but you can find them in inch/pounds, kg/M, Kg/cm and Newton/meter as well.

Mechanical wrenches use a rotational setting guide to adjust the torque setting. This is much like a micrometer, when you go to the 40-pound range on the shaft and then spin the collar to “6” for total of 46 foot pounds.

The modern version of the torque wrench is an electronic torque wrench. The electronic torque wrench you buy at your local NAPA Auto Parts Store uses an electronic sensor on a torsion rod to accurately measure applied torque. What is nice about these wrenches is that you get a warning as you approach the target torque, a beep when you reach it and even a digital readout of the actual applied torque. This means you know exactly how much the fastener has been torqued. The settings are adjusted through the digital readout with push buttons. One of the really nice features of a digital electronic torque wrench is the ability to change the scale, from inch/pounds to ft/pounds, kg/m, Kg/cm and Newton/m.

The nice thing about electronic wrenches is that they can be adjusted for foot pounds, inch pounds, and newtons.


The downsides of the electronic torque wrench are two fold. First it requires batteries, and if you don’t have replacements when you need it, it won’t work. Second is that some have plastic parts on them that can break like ours did if you aren’t careful. It has worked fine like this for years, but something to keep in mind.

How To Use A Torque Wrench

Using a torque wrench is simple as long as you follow a few rules.

  • NEVER use a torque wrench as a breaker bar. This will damage the calibration and ruin it. Torque can be applied in reverse for left-hand threads, but that is a different thing that breaking loose a fastener.
  • ALWAYS set the wrench to the spec you want and stop when it beeps or clicks. Don’t estimate and don’t over torque your fasteners.
  • NEVER take your torque wrench apart. Why would you even want to?

There are two different types of torque that you can measure with a torque wrench, clamping torque and rotational torque. While they are similar, they are not the same. Clamping torque is the final torque rating applied to a fastener, whereas rotational torque is the measurement of the force required to initiate movement and sustain movement, such as on the input yoke of a differential.  Clamping torque is measured with any torque wrench, but rotational torque requires a beam or electronic torque wrench because you have to watch the dial to get the reading, where a click-style wrench only clicks when it is at a specific rate.

Rotational torque measurement is most often required for setting up a differential, specifically the pinion preload. This is usually measured in inch/pounds. A beam wrench is the best for this, as you get accurate readings without a lot of hassle.

Measuring rotational force requires either an electric or beam wrench. The wrench must meet the specs, so a specific wrench for that task is usually used like this inch-pound wrench that reads from 0 to 60 inch points. A generic use electronic wrench usually does not go that low.

One note about modern fasteners. Many vehicles are using torque-to-yield fasteners, particularly in engine components. These are NOT reusable and require a specific torquing procedure that includes torquing to a specific measurement and then tightening an additional amount, usually 1/4-1/2 turn. Make sure you know what you are working with, this is paramount for a successful job.

Torque specs vary greatly by manufacturer, you need to be careful. Most modern vehicles use torque to yield bolts which are not reusable. They are torqued to a certain spec, then turned an additional 1/4 or 1/2 turn to yield the proper bolt stretch.

Ensuring that your critical fasteners are accurately torqued is, well, critical. Don’t guess when your life and others hang in the balance. If you think your steering linkage is correctly torqued and it isn’t, really bad things can happen. Don’t take the risk, get a torque wrench and use it.

Check out all the tools & equipment available on NAPA Online or trust one of our 16,000 NAPA AutoCare locations for routine maintenance and repairs. For more information on how to use a torque wrench, chat with a knowledgeable expert at your local NAPA AUTO PARTS store.

Related Articles

How To Calibrate A Torque Wrench In Two Ways : You Need To Know

Every car owner and homeowners need a torque wrench. You will never know when you will need to fasten some bolt or nut in your car and doing this manually is just impossible. Unless you have the strength of the Hulk or Superman then maybe, you can do it with your bare hands. But realistically, you will need a special tool for that.

Today you will learn how to calibrate a torque wrench.


How To Calibrate A Torque Wrench In Two Ways

This particular would require some adjustment on your end but don’t worry, with the right instructions, you will be able to figure it out. Others hire a professional to calibrate their torque wrench but I’m more into independence, which is why I’d rather do it myself. You must calibrate your torque wrench on an annual basis to ensure its quality and accuracy.

Before we move on, you must know that there are two ways on how to calibrate a torque wrench. One is through weight calibration and the other is called a fish scale calibration because you will need a fish scale tool for it.

Let us Start with Weight Calibration.

Method 1​

Materials That You Need
  • Torque wrench
  • Pen for marking (I suggest a sharpie)
  • Calculator
1. Marking:

Take your torque and make sure that you mark the center of its drive located at the back.

2. Measuring:

Take a look at the wrench and know where do you think you would comfortably place your hand as you use it. From there, measure that area and create a second mark on that place. Make sure that you know exactly how apart the distance of those two marks you just created.

3. Securing:

Tighten the square head using a bench vise. Keep in mind that there shouldn’t be any part of the wrench would touch that vise except the square head. You can them locate the handle using a horizontal position.

4. Computation:

Now, this part might require some of your math skills. You will need to line up the value of the torque to the marks of the two distances you created in step 2. You will need to multiply that by 20 pounds or 9.07 in kilograms.

5. Dangling:

This sounds fun but really, this part is kind of where it gets serious. You will need to dangle the weight of the torque from the marks that you made earlier.

6. Listening:

After doing that, you will need to listen to the tool and wait for that click to be heard. Once you heard the click, it is now time that you lift the torque’s weight and slowly places it to the head of the wrench. Do it until you stop hearing the click.

7. Marking Again:

Make some marks again just to guarantee you of the spots being right. Note that if you didn’t hear a click the first time, you have to place the weight a little bit far from the head of the wrench and do it until you hear that clicking sound. It is safe to do the markings by doing this step twice.

8. Calculation:

Count the distance that you created from the square head to the click marks that you made. Remember that distant count and multiply it by 20 pounds or 9.07 kilograms. The exact formula here is Ta=Ts x(D1/D2). The Ta stands for the torque setting, while the D1 is for the distance you found on your first marking and the D2 for your last

9. Checking:

You will need to go over the calculation again just so you are sure that you got the right calibration. Remember that the most important thing here is the distance that can be found from the center of the drive head.

That is where you usually hang the weight and not where you put your hand. People often make that mistake, which is really confusing if I don’t stress that out here.

Next stop, we have the Fish Scale Calibration. I have to say that this method is by far, the easiest! I highly recommend that you use this but it is also handy that you know how to deal with the weight calibration.

Moving on, here is how to calibrate a torque wrench using this fish scale method.

Method 2

Materials That You Need
  • Fish scale
  • Vise
  • Torque
  • Wrench
  • Calculator
  • Pen for marking
1. Securing:

Get a vise and start securing the wrench drive in it.

2. Fish Scale:

This is the part where you will need a fish scale to be attached at least one foot located at the center of the drive.

3. Measuring:

Know the weight of the pull that is on the scale to determine the exact setting for the wrench. After that, you can secure the wrench back in the vise.

4. Calculating:

Get a calculator to count the error in percentage. Repeat steps 1 to 3 by using various wrench settings and check the consistency of the error that is appearing.

5. Final Task:

Add the percentage error to the amount of scale that is on the wrench.

Visual learners could also learn from this tutorial video. Watch it from the link below.


It may sound intimidating at first to learn how to calibrate a torque wrench but with enough practice, you will get the hang of it and probably could do it professionally. You will be surprised on how much some people would pay you just to calibrate their tools.

This skill comes in handy, especially if you are stranded in the middle of nowhere and you need to fasten some bolts in your car.

The steps are pretty easy but it is understandable if you get lost from the whole calculation procedures for your first couple of tries. Trust me, that is not unheard of and you won’t be the only one who struggled with that in the beginning.

But don’t shy away from learning it and I’m sure that you will be able to calibrate it on your own. Cheers to independence and learning new things! Make sure that you always keep this tool in your tool kit wherever you go, so you know what to do in case of emergencies.

How To Use A Torque Wrench

When installing electrical equipment you’ll be required to use a torque wrench. A torque wrench is a special tool used to tighten nuts and bolts to a certain specific torque so that they do not stretch, break or become loose.

Manufacturer’s of electrical equipment require all screws, nuts, bolts, and connections be torqued to their specifications. It is specially calibrated to measure the amount of force applied to the nut or bolt that is being fastened.

This is a an easy tool to master as an electrician apprentice. You should become familiar with how to operate each and every type of torque wrench.

Torque is a measure of how much a force acting on an object causes that object to rotate

The wrench has a calibrated scale on which the amount of torque applied is displayed.

There are three basic types of torque wrenches commonly used today. Depending on the purpose they are meant to serve, the wrenches have different calibrations and additional tools.

The three main types of wrenches are the beam style torque wrench, the dial gauge, and the click adjustable torque wrench.

Although their sole purpose is to measure Torque, each has to be used differently. For you to get an accurate torque reading, you have to correctly use each torque wrench correctly.

Here is a quick guide on how each torque wrench for the best possible results.

Click Adjustable Torque Wrench (Ratcheting Wrench)

This type of wrench is what you’re more than likely going to be using on the job.

It has an internal spring and an adjustable handle. The required torque to be applied to the fastener is pre-set by turning the adjustable micrometer at the top of the handle.

Once the required torque is achieved, the wrench starts to click and becomes harder to turn or tighten the fastener.

They are preferred because the user can know when he reaches the desired torque without necessarily looking at the scale but feeling the resistance of the handle.

Here Is How To Correctly Use The Ratcheting Wrench:

  1. Unlock the handle and adjust it by turning the micrometer to the desired torque.
  2. Once you have the desired torque on the scale, lock the handle down.
  3. Connect the wrench to the socket and attach the fastener. Always ensure you use the correct size of the socket that holds on to the fastener properly.
  4. Apply force evenly and smoothly until you achieve the desired torque.
  5. Once the set torque is achieved, the wrench will start making clicking sounds. The spring will automatically snap and release the handle.
  6. Once you have finished using the wrench, reset the torque back to zero in order to release the pressure in the spring. Too much pressure in the spring held for too long, will reduce the ability of the spring to stretch and snap back into position over time.

Beam Style Torque wrench

The beam type wrench is the cheapest and least sophisticated wrench of them all. The beam style wrench can either have a flexible or fixed beam.

A flexible beam wrench has a pivoted handle while its fixed counterpart has a rigid beam. When you apply force to the handle, the calibrated scale deflects to the right or left to indicate the exact amount of torque exerted to the fastener.

Here Is How To Correctly Use The Beam Style Torque Wrench:

  1. Make sure you have the correct size socket to connect to the torque wrench. Connect the socket to the distal end of the beam torque wrench and ensure it is not loose.
  2. Once the socket has held on to the fastener correctly, pull the wrench smoothly and steadily. Always ensure that the direction of pull is at right angles with the handle. If the handle is flexible (has a pivot), evenly apply force to keep the handle positioned correctly at the centre of the pivot center.
  3. Tighten the bolt or nut until the scale reads the required torque.

When taking a reading from the wrench, always take a look at the scale from directly above it. If you read the scale from an angle, your reading will be affected by parallax errors.

You should also apply the force slowly especially when the bolt is getting tight otherwise the beam will bend. If the beam bends even slightly, replace it.

Dial Type Torque Wrench

This torque wrench is also relatively easy to use and are regarded as the most accurate torque wrench.

It measures its torque by using a needle that moves inside a vacuum dial when force is applied to it. The needle inside the dial moves both to the left and right directions.

Here Is How To Correctly Use The Dial Type Wrench:

  1. Attach the correct size socket and connect it to the fastener you intend to tighten.
  2. Hold the wrench at right angles relative to the handle of the wrench.
  3. Apply the force gently while tightening the bolts or nuts until the dial scale indicates the required amount of torque.

The precision of the dial type wrenches is extremely high.

If you realize that the dial indicates a reading on the scale even when there is no force applied to it, the wrench should be re-calibrated before being put to use. It is also the most expensive of all wrenches owing to its high precision.

After using the wrench for some time, you should have it re-calibrated to maintain the accuracy levels.

Calibration and Units of Measurements of Torque Wrenches

The calibration of torque wrenches is different for every wrench. The calibration is normally indicated on a sticker attached to the wrench. The calibration should be re-calibrated once the expiry date is reached.

The units of measurement are different as well. The scale can either be calibrated in Inch-pounds (in.lbs) or foot-pounds (ft.lbs). Foot-pound wrenches are normally preferred for large torques while their inch-pound counterparts are used for relatively smaller torques.


Answers To Questions You Need To Be Familiar With

Can a torque wrench be used to loosen bolts? A torque wrench should never be used to loosen anything.

Can I use a torque wrench as a breaker bar? See answer above.

Can I use impact socket on torque wrench? Yes, but you can’t use a regular socket on an impact wrench. Read more here.

Can I calibrate a torque wrench? In a pinch, yes you can. But it should be done professionally. For a DIY explanation of how to calibrate watch the video below.


How To Accurately Read a Torque Wrench

The torque wrench is a useful tool for applying a precise amount of force to nuts and bolts. This is important when dealing with sensitive equipment that will break when too much force is applied on the nuts and bolts, and which will not move when too little force is applied. Before using the torque wrench, here’s how you can read the measurement.

Type. Before anything else, you should identify the type of torque wrench that you are using. There are many types of torque wrenches that are commonly available today, such as the micrometer, the digital torque wrench, and the dial indicator. Various types of torque wrenches will be read in various ways. The type of torque wrench that you should use should depend on the types of projects that you are engaged in and the type of accuracy and force that the torque can provide.

Micrometer. When using the micrometer torque wrench, you will set the pressure or force level even before you begin tightening the bolts or nuts. As you tighten, make sure that you listen for a light sound that indicates that the force level that you have identified has already been reached. When using the micrometer, it is important that you work in a fairly quiet environment since some micrometers will only produce very light sounds that can be masked by background noise. As you use the micrometer torque wrench longer, however, you will learn to adjust to the sound levels even when the background noise increases.

Dial indicator. With dial indicator wrenches, a small dial is located in the wrench. Place the wrench head on the nut or bolt and start applying pressure. As you apply more pressure, the needle in the dial will show much force is being applied. Be sure that you keep your eye on the dial so that you do not add unnecessary force on the nuts and bolts. Some dial indicator models will allow you to input the force value that you want to reach. Once the value is reached, a LED bulb will glow or a sound will be played to remind you to stop applying more force. Generally, these types of torque wrenches are more accurate compared to micrometers.

Digital display. Perhaps the easiest torque wrench to use is the digital torque wrench. With the digital wrenches, you will only need to specify the force value. Next, start applying the force. A LED bulb or sound will be played once the force value has been reached.

Calibration. The digital torque wrenches are the most accurate of all types of wrenches. Keep in mind, however, that even the best torque wrenches need to be calibrated every now and then to ensure that they will be able to make accurate measurements of the torque applied. Adjusting and recalibrating the torque wrench can usually be done by following the instructions written in the torque manufacturer’s manual.

Once you know how to read the torque wrench, applying the exact amount of pressure for your home projects and repairs will be easy.

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