Straight female stud couplings, G thread
Threaded fittings
Straight female stud couplings with a G thread take a precision steel tube at one end via cutting ring plus union nut, while the opposite end carries a parallel Whitworth female thread. They therefore screw onto an existing male spigot on a valve, pump or pipe run, rather than into a tapped port. The category holds 94 versions, covering female threads from G 1/4" to G 1-1/4" plus tube outside diameters from 6 L to 42 L as well as 6 S to 38 S.
Two independent dimensions govern the choice: the G female thread of the socket, which must match the spigot on the equipment, plus the tube series at the cutting ring end. Light series L differs from heavy series S in cone angle as well as clamping ring, so the two series cannot be mixed. Available materials are zinc plated steel along with stainless steel 1.4571, both also supplied as a body without nut plus ring.
First fix the G female thread to suit the male thread of the mating part, then choose the tube series of the installed line separately. The two sizes do not run in step: G 3/8" is combined both with tube 12 L as well as with tube 10 S, while G 1" pairs with tube 28 L. A parallel thread does not seal in the thread flanks themselves, so sealing takes place at the spigot face. On rebuilds of existing lines, the versions without nut plus ring avoid replacing the tube.
Rigid pipework on hydraulic power units, presses plus machine tools wherever the equipment or an existing nipple offers a male G thread that the steel tube has to reach. Equally common when connecting pressure gauges, shut off cocks plus manifold rails fitted with pipe thread spigots. Versions in 1.4571, such as G 1-1/4" on tube 30 S, serve chemical plants, outdoor lines as well as wet areas.
