The accuracy and the consistency of the STE hardness tester is due to the original principle of the loading  system.

The applied force causes penetration of the indenter into the surface with a load determinated by the calibrated pin, which breaks at 1580 kp.

The value of Brinell hardness is obtained by reading the diameter of indentation on readout charts which assure proper correlation between load applied and impression diameter, and are provided with each bag of pins.