ASTM D1415-18 + Redline

1.1 This test method covers a procedure for measuring the hardness of vulcanized or thermoplastic rubber. The hardness is obtained by the difference in penetration depth of a specified dimension ball under two conditions of contact with the rubber: (1) with a small initial force and (2) with a much larger final force. The differential penetration is taken at a specified time and converted to a hardness scale value.