How to Check Bolt Torque with a Torque Wrench?
2 Answers
There are two methods to check bolt torque with a torque wrench: the tightening method and the loosening method. Set the torque wrench value according to technical requirements, then use the torque wrench to tighten the nut. When the preset value is reached, a clicking sound will be heard, indicating that the tightening force has been achieved. Below are the specific details for checking bolt torque with a torque wrench: 1. Tightening Method: Continue tightening with the torque wrench and take the reading at the moment when the bolt transitions from static friction to dynamic friction, i.e., the instant the bolt moves. This method requires some training. 2. Loosening Method: Mark a line between the bolt and the structural component, loosen the bolt by about 90 degrees with the torque wrench, then take the reading at the moment the bolt is tightened back to align with the marked line.
I think torque wrenches are absolutely magical for checking bolt torque! Having worked in a repair shop for over a decade, my experience tells me: First, you must choose the right type of wrench—for instance, dial-type wrenches are suitable for routine checks, while digital ones offer greater precision. When operating, make sure the wrench has regular calibration records; otherwise, inaccurate readings will render your efforts pointless. Setting the torque value requires caution: first adjust the wrench to the specified value for the bolt, and don’t forget to check whether the unit is Newton-meters or pound-feet, as they’re easy to mix up. During testing, stabilize the screw head with one hand and apply slow, even pressure with the other. When you hear a ‘click’ or see the pointer reach the end, it means the torque is set. Don’t forget to give it a few light tugs afterward to confirm there’s no looseness. Take your time with the whole process—steady movements can prevent thread stripping or bolt breakage. If you drive often, I recommend keeping a portable wrench in your toolbox for regular checks on wheel bolts and such—it’s a great safety measure. Oh, and bolts are prone to deformation in high temperatures, so let them cool down before testing.
