Rubber Hardness Scale

Shore durometer hardness is a measure of the resistance a material has to indentation.

Rubber hardness scale. There are several scales to measure the hardness of an elastomer used for materials with different properties shown in the diagram below. As you can see from the graphic there is overlap on the different scales. The shore a hardness scale measures the hardness of flexible mold rubbers that range in hardness from very soft and. For example a material with a shore hardness of 95a is also a shore 45d.

For example a material with a shore hardness of 95a is also a shore 50d. Shore who developed a measurement device called a durometer in the 1920s. Shore durometer is a scale used industry wide to measure the hardness of rubber and plastic materials. These tests are designed for use with samples approx 6mm thick and a surface area sufficient to permit at least 3 test points 5mm apart 13mm from any edge.

A flattened cone is pressed through a spring into the surface of the rubber. A chart showing general hardness comparisons is below. Tpes can range from 10 shore 00 up to 72 shore d spanning all three hardness scales however the most commonly used is the shore a scale. Thus if you need a rubber or o ring durometer that feels like a running shoe sole review our rubber hardness chart below then pick shore 70a.

The hardness of rubber measured by means of a durometer is expressed in the unit shore a. Elastomeric materials are usually measured with either a shore a scale durometer or an irhd dead load system. Hardness may be defined as a material s resistance to permanent indentation. Hardness is an important consideration in sealing materials.

Shore hardness and how it relates to other properties. The durometer scale was defined by albert f. When selecting rubber sheet there are various thicknesses and lengths but also varying hardnesses. The most commonly used gauges for measuring the hardness of rubber are the durometer and the irhd meter.

The a scale is for softer materials such as rubber while the d scale is for. Some of hapco s materials are available in both shore a and shore d. Named after its inventor albert ferdinand shore shore hardness offers different scales for measuring the solidity of different materials shore was born in 1876 and lived until 1936 creating the shore scale in the 1920s. Lower numbers indicate less resistance and softer materials.

A rubber durometer of shore 70a is the most commonly chosen material hardness for all applications. Higher numbers on the scale indicate a greater resistance to indentation and thus harder materials. Generally most rubber materials fall under the rubber durometer scale of shore a. Hardness is one of the most commonly used properties to specify a rubber.

Two such scales using slightly different measurement systems are the shore a and shore d scales.