BS 1389:1960

Dimensional drawings of threaded connexions, coupling nuts, coupling nipples, hose couplers for use with gas welding and cutting equipment. ⅛, ¼, ⅜, ½ and ¾ in BSP.F threads. Left-hand threads and notched hexagons are used for combustible gases and right-hand threads and plain (unnotched) hexagons are used for non-combustible gases.