ALTANA Hoffman Scratch Hardness Tester Manual - Manual (Page 6)

5
Calibration Procedure
• At this point, a small upward tap on the scale
arm should cause it to settle in a higher
position; the scratching tool is not in contact
with the surface
(position 2).
The optimal calibration is reached when the
smallest amount of force is required to raise the
scale arm from position 1 to position 2. If the scale
arm will not stay in position 1 on its own and goes
directly to position 2, the counter weight needs to
be shifted to the left. If the lifting force required to
switch from position 1 to position 2 is too great,
the counter weight needs to be shifted to the right.
Once calibrated the counter weight should not
need further adjustment, but it is recommended to
check the calibration on a regular basis.