Contact Blocks—Cold-rolled steel contact blocks shall
be used between the test specimen and the platens of the
machine. These blocks shall be 11⁄2 in. (38.1 mm) square by 5⁄8
to 3⁄4 in. (15.9 to 19.1 mm) thick, and the contact faces shall be
surface ground until plane and parallel. The contact blocks
shall be resurfaced, if necessary, after each strength test, and
may be reused only so long as the thickness remains over 1⁄2 in.
(12.7 mm). If the contact block is cracked during testing, it
shall be replaced.