User:KDS4444/List of shore durometers

The durometer score of a substance is a measure of its ability to resist permanent indentation as measured by an instrument also referred to as a durometer. Such measurements are usually applied to various polymers including elastomers, thermoplastics, and thermosets.

The durometer scale actually consists of 12 overlapping scales, each intended to measure a hardness in a different range of applications. According to the American Society for the Testing of Materials standard number D2240, "Hardness", these scales have the following names ranging from softest to hardest: A, B, C, D, DO, E, M, O, OO, OOO, OOO-S, and R. Because the ranges of these tables overlap, a material can have a score on more than one table. The most commonly encountered scores are shore A (for rubbers) and shore D (for heat formed plastics and thermosetting resins). Only these two shore scales are included in the table below.

Scores are achieved by with an indenter loaded by a spring. The indenter pushes down on the material with a given force that depends on its scale of measurement. A shore A indenter, for example, pushes downward with a force equal to 1.812 lb, while a shore D indenter uses 10 lb. Results are indicated in degrees (°) of difference between a small, initial force and the final force. The maximum penetration of a scale ends at 0.097-0.100 inches (2.5 mm) of penetration, corresponding to a theoretical score of zero° on that scale, while a score of 100° means no penetration was observed°. Scores are inherently somewhat ambiguous, and a variation of 5° between different measurements of the same material is common.

Note that shore hardness is only one measure of a material's characteristics. Stiffness and compressive modulus are other equally important qualities of an elastomer.

The following table represents typical shore hardnesses of various materials measured at given scales.