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An approved machine shall compromise the following: A first rigid platen connected
to a force-measuring device and a second identical and parallel platen which can move
axially with respect to the first platen, such that when a ball is placed between them it
can be compressed along its diameter between the platens and measurement taken of
its deformation at a predetermined force. The platen design shall be as shown in
Figure 3.
Note: The Stevens machine is deemed to be compliant with the above.
Figure 3. Deformation – Test Method ITF TB 03/01. Specification of platen
design (to be used for both platens). All dimensions are given in millimetres.
Rebound – Test Method ITF TB 04/01: The ball is dropped from a height of
254 ± 0.3 cm (100 ± 0.1 inches) (measured from the bottom of the ball) onto a
smooth, rigid and horizontal block of high mass and the rebound height is measured
(again to the bottom of the ball). See Figure 4.
