The Screw Joint Testing Unit, "MSCT", represents the simulation of a tightening set consisting of a screw and a nut on two rectangular shaped beams.
A very precise torque wrench performs the tightening through a threaded rod and a flywheel. The screw and nut join two steel bodies (rectangular-shaped bars), which are separated at a certain distance. The action of the screw and nut produces an elastic strain in the steel bars generated by the axial tension produced in the screw body. The displacement produced (strain) is collected by a dial indicator enabling the analysis of the torsional torque, with which the tightening has been performed.
The screw head presents a flat bearing that allows friction to be negligible at this point. In this way, you can calculate the friction of the screw thread itself with the nut.