This British Standard specifies requirements for:
a) external micrometers having a frame holding a micrometer spindle and nut on one side opposite a fixed anvil on the other
b) external micrometers having a frame holding a micrometer and spindle and nut on one side opposite an anvil on the other, and providing for two or more alternative ranges of measurement effected by means of interchangeable or sliding anvils
c) setting gauges for micrometers.
This British Standard covers requirements for the frame material, general design of the frame, micrometer screw, spindle, thimble and barrel, zero settings, packing and marking of external micrometers.
This edition of the standard incorporates modifications of the 1939 edition to add provisions for micrometers with measuring ranges of 0 to ½ in. and from 12in. to 24in. (with their corresponding metric equivalents) and to include requirements relating to micrometers with interchangeable anvils and various measuring ranges up to 24in. (600 mm).
