BS 21:1985 Specification for pipe threads for tubes and fittings where pressure-tight joints are made on the threads (metric dimensions) (AMD 6633) (Withdrawn)
Range of threads from one sixteenth to 6, together with thread forms, dimensions and tolerances, designations; includes appendices for recommended gauging systems and methods of use of gauges. Requirements for jointing threads for taper external threads, for assembly with either tapes or parallel internal threads and for longscrew threads for longscrews specified in BS 1387.
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