8.3.1
Longscrews (connectors) shall be made only from heavy tube and shall be supplied single or double, as may be specified, and shall conform to the appropriate dimensions given in Table 3.
8.3.2
The sockets shall be suitably faced on the end which the back nut abuts. The face of the back nut which abuts against the sockets shall be concave at an angle of approximately 15°.
8.3.3
The parallel threads on the longscrew and in the socket shall, in addition to complying with the appropriate requirement of IS 554, be of such a size that the socket runs on the connector hand-tight without perceptible shake.
This type of joints is permissible for low pressures, but is not recommended for higher pressures or for work in which there are wide variations of temperature.
NOTE — When it is necessary to use longscrew for running joints, the threads of the longscrew which accommodates, the running socket and back nut shall be parallel.