You often hear of Shore A and D hardness scales… but are these the only ones?
In fact, they are much more than you imagine, here they are: A, B, C, D, DO, E, AO, O, OO, OOO, OOO -S, M and AM.
There’s a reason for all this variety, though.
You should know, in fact, that Shore hardness test scales refer to a specific hardness range: usually D scale is used for hard plastics, while A scale is used for less rigid ones.
And so far, nothing new.
But the fact is that polymers and elastomers are of various kinds – let’s think about gums and gel-like materials, for example – and relying only on two scales inevitably leads to inaccurate results.
Let me be clear.
Would you use a kitchen scale to measure a bag of cement?
Or, would you use a yardstick to measure the diameter of a screw?
It sounds absurd but that’s exactly what happens when you don’t use the right Shore hardness tester scale.
If you have hardness results in Shore A or D that exceed 90 Points, you are definitely stumbling on these ridiculous examples.
So, what can we do?
We suggest to stay in the hardness range between 20 and 90 points for Shore A and D.
With the caution, however, that the closer the value is to these extremes the more it becomes necessary to change the scale.
For all the other stairs, we created a practical table easy to use, you can find it here.