The Scleroscope test consists of dropping a diamond tipped hammer,
which falls inside a glass tube under the force of its own weight from
a fixed height, onto the test specimen. The height of the rebound
travel of the hammer is measured on a graduated scale. The scale of the
rebound is arbitrarily chosen and consists on Shore units, divided into
100 parts, which represent the average rebound from pure hardened
high-carbon steel. The scale is continued higher than 100 to include
metals having greater hardness.
In normal use the shore scleroscope test does not mark the material
under test. The Shore Scleroscope measures hardness in terms of the
elasticity of the material and the hardness number depends on the
height to which the hammer rebounds, the harder the material, the
higher the rebound. Advantages of this method are portability and
non-marking of the test surface.
The Durometer is a popular instrument for measuring the indentation
hardness of rubber and rubber-like materials. The most popular testers
are the Model A used for measuring softer materials and the Model D for
The operation of the tester is quite simple. The material is subjected
to a definite pressure applied by a calibrated spring to an indenter
that is either a cone or sphere and an indicating device measures the
depth of indentation.