BS 939:1977

Squares of try-square type in three grades of accuracy: AA, A, B; cylindrical squares in grade AA; solid form block squares in grades AA, A; open form block squares in grades A, B. Nomenclature, designation, sizes, material, manufacture, design, accuracy, marking, protection, testing.

Cross References:
BS 1133:Section 6
BS 1133:Section 19
BS 1134
BS 1452
BS 3643


Replaces BS 939:1962.

Incorporates the following:
AMD 4239 published 29 April 1983