How To Re-calibrate A Torque Wrench. To perform a torque wrench calibration on your own, you need to determine the calibration ratio and multiply that amount by the required bolt torque. Now each time you use the wrench you will need to use this calibration ratio.
Approach final torque slowly and evenly. Make your measurement in inches and for easy calculations, use a whole number. Alternatively a torque tester with an appropriately ranged torque sensor should be used.
Against the clock to reduce power.
If your wrench is off then this setting will not be at the 50 ft pound mark but at a different distance. Against the clock to reduce power. Measure and mark the length to your reference point. In general, iso allows 4% to 6% above or below the torque indicated by a torque wrench’s setting in.