The difference and conversion between Shore(A) and Shore(D)

Generally speaking,Shore(A) is used to measure the hardness of soft plastics or rubber,Shore(D) is used to measure the hardness of hard plastics or vulcanized rubber.The shape of indentor from A-form sclerometer is frustum cone and the shape of indentor from D-form sclerometer is conical.

Test method of Shore(A) and Shore(D) are different.It could not be converted between them in the ordinary way.So if you want to measure plastics under 90 Shore(A),A-form sclerometer is  the best choice. If Higher than 90A,D-form is the best.

But we have two kinds of approximate conversion method.

   1、 D=A-50  ；

   2、A=0.173D+86.58.

If you want accurate hardness, it is recommended to use the A-form sclerometer for soft plastic, D-form sclerometer for hard plastics.

BTW:other special presentation options of hardness.

1.Shore(C):it is usually used to measure ultrasoft plastics which hardness is under 0 Shore(A),The hardness of Thermoplastic Elastomers(TPE) and
Thermoplastic Rubber(TPR) which has good Oil absorbing can be made to under 0 Shore(A)