... 100 degree angle, it can not be used. If the hardness gauge is used on the shelf of fixed weight, one can lift the hand ... laboratory. When measuring the sample, A-type hardness gauge’s value is more than 90 degrees, it is recommended that one should use D ... gauge. When A-type hardness gauge’s value is 10 degrees, it is not accurate, and the measurement result can not be used. After complete ...