6.9. Bolt Tension Calibration

6.9.1. The RCSC Specification discusses a “calibration device capable of indicating bolt tension.” What is an example of such a bolt tension calibration device?

One such device is the Skidmore-Wilhelm Bolt Tension Calibrator, manufactured by the Skidmore-Wilhelm Manufacturing Company ( When a sample bolt is installed in the “Skidmore,” the tension is measured on a dial gauge. Thus, the appropriate torque for use in the calibrated wrench installation method may be determined, or the proper tension resulting from the turn-of-nut, alternative design bolt, or direct tension indicator methods may be verified. It is not intended that the use of other similar devices be excluded by this discussion.