You must know how to summate torque for tightening bolts to ensure that your application is functional and safe. Errors in torque calculation can result in expensive failure, including the time and hassle of replacing broken equipment.

What is Torque?

Torque is a twisting force measuring force multiplied by distance. It is the awarding of force acting at a radial distance to create tension in threaded fasteners. When the nut and bolt are tightened, the thread converts the practical torque into tension, which is converted into a clamping force. It is measured in foot pounds in the United States, and we have included each of our products' measurements on their production page.

Why Is Bolt Torque Important?

You lot must ensure that your awarding has the appropriate amount of torque and tension to avert bolt shearing (sliding autonomously) and tensile (pulling autonomously) forces. After the nut has been turned onto the bolt, boosted torque causes the nut to plow and stretch the commodities. When the bolt stretches, it becomes a solid spring that clamps the components together. The components won't be pulled apart if the clamp load is not exceeded by the tensile load. Nether shear loads, the increased friction prevents relative movement of the components, preventing material failure.

Determining the advisable amount of torque depends on the metal properties of the commodities and the purpose of the bolt. Essentially, you need to make sure that yous accept the right materials for your application. Having the wrong materials, or an incorrect torque calculation can be potentially hazardous. An under-torqued bolt will deform and won't be able to provide as much clamping force as needed, while an over-torqued commodities volition interruption.

How to Summate Torque

To decide an estimated torque value, use the standard torque formula:

T = DFK

This formula expresses the human relationship between the load in a bolt and applied torque. The "D" represents the commodities's diameter, the "F" is the axial bolt strength, and the "G" represents "k-factor" or "nut gene" which is a variable based on the use or absenteeism of lubrication. The chiliad-cistron for a non-lubricated joint is 0.2. Non-lubricated joints are typically referred to equally being "dry out", and the procedure of torquing downwardly the joint being known as "dry out-torquing". The k-cistron of a lubricated joint is typically between 0.fifteen and 0.18.

A non-lubricated or dry joint has more than friction betwixt components which requires more torque to be applied in order to accomplish the aforementioned deflection/travel equally a lubricated joint. These factors are best adamant after a swell deal of experimentation through extensive testing.

An Instance of Computing Bolt Torque

For this example, our M will exist 0.2 for a non-lubricated joint. Our bolt'southward diameter volition be 0.five inches, and the centric bolt force will be 11,175 lbs:

T = 0.ii x 0.5 x eleven,175

T = 1,117.v inch lbs.

And so, catechumen to foot pounds past dividing by 12:

T = i,117.5 / 12

T = 93.125 ft lbs

Our T in this equation is approximately 93 ft. lbs.

Use a Torque Wrench to Calculate Torque

Torque wrenches are precision instruments that will allow you to mensurate and utilize the proper torque for the results you need. Torque wrenches will calculate the amount of torque in either analog or digital formats. When calculating torque, always remember that torque wrenches are not perfectly accurate. If yous'd adopt, please contact us regarding the optimal torque for various combinations of bolt diameter, thread type, and form or grade.

How to Verify Your Torque Adding

Once you have calculated your torque, exist sure to double-check to confirm that the calculation is right to ensure the safety and proper functioning of your equipment. A pocket-sized error could result in a large discrepancy in your final figure. To verify your torque calculation, utilize these three proven methods:

The Starting time Motion Test

After you've tightened your fastener, apply a torque audit wrench to slowly apply force in the tightening direction until yous notice the first movement in the fastener. The reading is a reliable indication of the originally-applied torque. This is the most trusted measure out of torque afterwards tightening.

The Loosening Test

This is the same as the showtime method, except in the reverse direction. The moment in which you experience the first loosening movement will create a good reading on your audit wrench.

The Marking Test

Marking the surface of the fastener later on tightening the bolt or nut, and continue that mark to the surface that information technology'south being fastened to. Now loosen the fastener, wait a moment, and re-tighten until the marks you just fabricated align. The torque required to get to that signal is a skilful reference to the original torque used.

Questions?

If you take questions virtually how to calculate the tightening torque of bolts for your application, delight fill out the contact form at the bottom of this page, or requite u.s.a. a call at 440.721.8350.