
Specification for engineers' squares (including cylindrical and block squares)
出版:British Standards Institution

專家解讀視頻
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.
? British Standards Institution 2013
Replaces notes:
Replaces BS 939:1962.
Amendment notes:
AMD 4239 published 29 April 1983