The Rockwell HardnessTesting Machine

This picture contains active zones. Click and Explore The testing machine has a table (1) which holds the sample and raises it into contact with the indenter using the screw (2). After contact, the screw is turned until the grove in the stem below the dial gauge (3) disappears and the pointer (5) is in the vertical position. This applies a minor load to the sample. The bezel of the gauge is then rotated so that the "set" arrow on the gauge is directly behind the pointer. The crank handle (4) is then moved backwards to load the indenter and push it into the sample. When the pointer comes to rest, pulling the handle (6) forward lifts the major load from the indenter, allowing the sample to relax elastically, but leaving the minor load applied. The sample's Rockwell hardness number can be read from the new pointer scale position (7) .