Skidmore Model HS

Skidmore-Wilhelm Bolt Tester

*Skidmore-Wilhelm bolt tension calibrators available for rent, please see our Tool Rentals section or call us today!


skidmore_model HS calibratorMODEL HS Portable Bolt-Tension Calibrator. 

This unit is designed for larger bolt sizes (1" to 1-1/2" and 27MM to 42MM).
Testing for maintenance

The Model H Calibrator can be used in maintenance programs to develop accurate records of impact tool performance. In this program, new impact wrenches are tested for bolt tension output at specific power settings. Any subsequent bolt-tension drop indicated by a lower reading on the dial signals need for maintenance. File card records can be kept by serial number to show last test and performance. Hardened Test Set—three hardened, ground Bolt and Nut Test Sets can be supplied in standard bolt sizes of 1”, 1- 1/4”, and 1-1/2” for use in maintenance test procedures. These wear and deformation resistant test sets provide a constant standard for comparative testing. Engineering Preload Specifications— Standard specifications for bolt-tension or joint preload can be established for different types of interface materials. Effects of plating and lubrication are just two of the variables that can be tested. The calibrator also can be used to establish preload criteria, such as bolt-tension required for yield and ultimate load expressed in pounds. This provides a practical working set of figures.

Torque-Control Wrenches:

Simple to calibrate! Run up nut with impact wrench until wrench stalls. Read the dial for pounds tension. If reading is too high or low, adjust torque setting accordingly and repeat using new bolt and nut.

Conventional Impact Wrenches:

Set wrench air line regulator at desired power value. Run up nut until it stops rotating. Again, read the dial for pounds tension. Adjust regulator as necessary until wrench delivers desired bolt-tension dial reading.


Using the Model H Calibrator, determine “snug” condition (point at which tool begins to impact). From snug condition, operate wrench until proper rotation is obtained. Resultant bolt-tension is shown on the dial.