Hold tight the handle directly to the bottom without putting the specimen in the opening othe hardness tester. As shown in Fig. 3, regulate the full-scale adjusting screw with a small screwdriver to bring the indicator at Scale 20. If the pointer pointing at a smaller value than 20, the adjusting screw should be regulated clockwise; if the indicated value is greater than 20, the adjusting screw should be regulated anticlockwise. If the pointer can not be set to the full scale 20 by regulating the adjusting screw, replace the indenter.
Screw off the pivot screw, and take out the lower handle from the main frame, then remove the dial head from the indenter cylinder, while leaving the cylinder in the frame. Then the adjusting screw with grooves can be seen in the indenter cylinder. Rotate the adjusting screw with the special wrench equipped with the instrument. If the reading of the hardness block is smaller, rotate the adjusting nut anticlockwise; otherwise, rotate the adjusting nut clockwise. When the nut is rotated 1/4 circle, the scale reading will change 2-3 units.
Reassemble the tester and verify the hardness block after regulating it.
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