BS 5590:1978 pdf free.Specification For Screw Thread Metric Series Measuring Cylinders. BS 5590 relates to measuring cylinders for standard pitches of ISO metric threads given in BS 3643. The cylinders described are intended for use on threads of small helix angle, i.e. less than 5°. Cylinders for measuring the pitch diameter of Unified, Whitworth form and B.A. threads are specified...