The main element of the unit is a slotted, elastically deformable steel block. By tightening the bolt joint, the slotted area is deformed, thereby generating an axial tension force in the bolt. The resulting deformation is recorded by a mechanical dial gauge, and is directly related to the bolt tension force generated. The bolt joint is tightened and slackened using a special torque wrench, which can be set sensitively with the aid of a threaded spindle. By using an axial bearing, the head friction of the bolt can be largely excluded, so that only the friction of the threaded joint is measured.
  The well-structured instructional material sets out the fundamentals and provides a step-by-step guide through the experiments.

- Axial tension force in a bolt joint dependent on the tightening torque or

  the elastic deformation of a slotted block
- Measurement of the breakaway torque, including for different fitting

  situations of the bolt joint
- Measurement of thread friction and overall friction