What does NM Mean in Torque Wrench?


When selecting a torque wrench, the rating is very important. There are several ways of rating a torque wrench. You may see Nm indicated on this tool in most parts of the world. In this article, we need to find out, what does NM mean in torque wrench? We will also consider how you can read Nm on a torque wrench. We will also take time to look at what a torque wrench is and what it is used for on a vehicle. This and many more questions about NM will be answered. Let us start with the key question about nm.

what does NM mean in torque wrench

What does NM mean in Torque Wrench?

The letters nm on a wrench stand for newton meter. This means you are using a torque wrench in newton meters. That’s means one newton force is applied through one meter length lever. This is the Standard international unit for torque apart from the lb-ft. The unit brings together Newton, an SI unit of force and a meter which measures displacement. Therefore, when a force is applied over some leverage, the result is torque. By definition, torque refers to the turning effect of a force. Therefore, the unit also represents the amount of twisting-effected to be applied. If such a capacity is exceeded too much, a material can shear away in failure.

How can I read Nm on a Torque Wrench?

Reading the Nm on a torque starts by noting the number on the datum line. There are two main groups of numbers. The first set of numbers is displayed above the rotating member. You also need to note that there is lb-ft and nm on the same wrench. Focus on the Nm and read the course number above the datum. In this case, you are focusing on the nm torque wrench. Therefore, the datum or demarcation is indicated by a solid vertical line. Check the number directly on top and note it.

For example, if this number is 21.6 Nm, write it down. Then check the number at the bottom. This is the number coinciding with the vertical line. If this number is 0.4 Nm, you can add the two numbers. The total torque will turn out to be 21.6 + 0.4, and you read it as 22 Nm. When using a digital torque wrench, you will read the number directly. You will also take time to listen to the warning sound when the set torque is reached.

What is a torque wrench and its usage in a vehicle?

A torque wrench is a tool used for tightening a component to a specific torque. It could be tightening a set of nuts, bolts, or fasteners as you apply it. The manufacturer specifies this torque with maximum safety, optimum operation, and other standards in mind. When followed in line with the manufacturer’s spec, you apply the best practices. This way, you even allow your equipment to work safely and reliably over a long period.

There are several uses for a newton meter torque wrench on a vehicle. When assembling a cylinder head, you need the correct torque spec for spark plug and each bolts. You also need to use a torque wrench when tightening wheel nuts. Other areas where this is needed include when installing the power train, differential unit, oil pan, and many more.

How strong is 1NM torque?

Applying 1 Nm means that a force of 1N is applied perpendicular to an arm of length 1m. By conversion, this is equivalent to around 0.738 pound-feet or 8.85 Inch-pounds. This is a very small torque that you can easily work even with a shorter wrench. Bigger torque specs can range from 10 Nm, 12 Nm, 20 Nm, 25 Nm, 30 Nm, and many more. The manufacturers freely select different torque specs with a variance of 1Nm.  That is why you can have a torque spec of 20 N and the next one can even be 21 Nm.

What is a good torque NM for a car?

Different cars come with different capacities. Some vehicles may have a torque output from the engine of around 400 Nm, while others can go up to 500 Nm. When assembling such an engine, the best toque to be used also varies. That is why newton meter torque wrenches come in different sizes. Depending on the part you are tightening or loosening, this may vary. For example, tightening wheel nuts can range from 90 Nm to 120 Nm. When you are working on the cylinder head bolts, it ranges from 10 Nm to 120 Nm. Once again, this is monitored by the size of the engine. The bigger the engine, the higher the torque spec. It is not possible to have uniform values of torque for all vehicles.

good torque NM for a car

How tight is hand-tight torque in NM?

Hand tight can go up to 25 Nm. This is on condition that you do not use extensions or a long ratchet. If any other extensions are included, this value cannot hold. At the same time, this should not be confused with finger tightening which is between 0.02 Nm and 1 Nm. This one refers to the initial installation that allows one to tighten only a few threads in some cases. Then later you can use a tool to tighten it as required. It is also worth noting that even hand tight requires confirming. You may easily go above the numbers targeted if this remains open-ended.

Conclusion

What does NM mean in torque wrench? A torque wrench allows you to work in line with a specified amount of torque. The Nm on the wrench indicates newton-meter. This represents the tightness required for a particular component. You can take time to read the torque wrench correctly when in use. Any errors in reading the torque can lead to wrong results with disastrous consequences. In each case, select the correct torque wrench for the application. For a particular vehicle, stick to the service manual for specifications. You do not have to start guessing or using average values.

Shafiqule

Mr. Shafiqule Islam is a graduated Mechanical Engineer and has more than 15 years experience of repairing and maintenance of different brand vehicles like Toyota, Mitsubishi, Ford, Mercedes, BMW etc. He is also giving training to Mechanics. He has started writing to share his practical knowledge to Vehicle Owners, Drivers and Mechanics to keep their cars at best fit.

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