How to Torque Bolts

by Christian Killian

torque wrench in box image by Christopher Dodge from Fotolia.com

Properly setting the torque on a nut or bolt requires you to use a torque wrench. The nuts or bolts you are working with, though they are steel or metal, are designed to stretch when tightened. A specific amount of torque applied to them will stretch them to the required amount, keeping them tight. Torque is used on fasteners from lug nuts to bolts in the engine or interior of your car. Applying that torque properly is critical to the success of the fastener in its intended use.

Step 1

Locate the torque specification for the fastener you are working with. In most applications, the manufacturer will supply these specs and publish them in repair or owner's manuals. The specification may be in foot-pounds, inch-pounds or a metric equivalent. Make sure you have a torque wrench to fit your needs.

Step 2

Set your torque wrench to the specified torque. On most modern torque wrenches, the torque is set by turning the handle of the wrench until the top edge lines up with a mark on the barrel of the wrench. The torque wrench may be marked in standard and metric units, so double check the scale you are using on the wrench or you may over-torque the fastener.

Step 3

Choose an appropriate-size socket to fit the fastener you are working with and install it on the torque wrench. Snap the socket onto the square drive of the torque wrench just like you would on a ratchet. Make sure the socket fits the fastener correctly, as applying torque will damage or strip the fastener.

Step 4

Place the socket and torque wrench on the fastener and tighten the bolt, holding the torque wrench by the handle at the end of the wrench. Rotate the torque wrench slowly and smoothly, continuing through the arc until the wrench clicks. The click indicates that you have reached the desired torque. Do not tighten beyond this point or damage with occur to the fastener.

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