ABSTRACT
The test is also standardized as BS 2782 Method 365B [3], which is identical to the ISO method, and ASTM D2240 [4], on which the ISO method was originally based. In both methods the test piece to be measured must be 6 mm or more thick (3 mm is allowed in ASTM for the D scale) to avoid the hardness value being affected by the harder surface on which the test material is resting. To avoid edge effects, measurements should not be made nearer to any edge than 12 mm. It is clear, therefore, that a standard hardness test requires a relatively large and flat sample of material. Where these criteria are not met, only apparent hardness can be quoted, and it is important that deviations from standard
Figure 1 (a) Indenter for Type A durometer. (b) Indenter for TypeD durometer.
