Does it matter whether you tighten the bolt head or the nut?

Last Updated on July 1, 2020 by Marsh Fasteners

It is safe to say that working with bolts, nuts, and other fasteners require care and know-how, especially if you want to avoid loosening, thread stripping, and breakage. There are several questions that come up regarding the actual tightening of hex bolts, carriage bolts, lag bolts, tap bolts, and more. Many people aren’t sure whether to tighten the bolt head or the nut. These questions include:

  • Should torque be applied to the bolt head or the nut during tightening?
  • Will one method over another cause breakage or are both equal?

There is no simple answer to this as in some instances, it is perfectly acceptable to tighten the bolt head while holding the nut in place. In other situations, it’s acceptable to tighten the nut. It all depends on the application and the condition of the product or material being worked with. While in some situations you can apply torque to either bolt head or nut and enjoy a tight connection, there are circumstances where you should apply torque to one and not the other including the following:

  • Interference is being caused by the holes you are bolting through:

In this scenario, it is better to apply tightening force to the nut.

  • The bolt head and the nut have different shapes and diameters:

In this situation, apply tightening force to the smaller bearing face. For instance, if the bolt head is smaller than the nut, you should tighten the bolt head and not the nut.

  • Securing different materials:

Apply tightening force to the part that’s against the material with a lower coefficient friction capacity. Torque on the side that’s likely to produce the least friction.

  • Long bolts are being utilized:

In this scenario, the tightening force must be applied to the nut to avoid torsional wind-up issues.


It is always recommended to follow the manufacturer’s torque guidelines to ensure the best fit and the most durable installation.

Find bolts, nuts, and other fasteners and learn whether to tighten the bolt head or the nut with the assistance of Marsh Fasteners

At Marsh Fasteners, you will find a selection of carriage bolts, hex head bolts, lag bolts, tap bolts, eye bolts, carriage cap nuts, acorn cap nuts, coupling nuts, hexagon nuts, metric nuts, machine screw nuts, serrated flange nuts, and more. Contact us via email or telephone for more information and advice on bolts, nuts, and fasteners at Marsh Fasteners today.

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