9Pcs Pipe Threading Set (BSPT)

The thread form is BSPT, and that is the specification to check before anything else. BSPT is British Standard Pipe Taper, the threading standard used across Sri Lanka on water and gas pipework, so this is the set that matches the fittings, valves and galvanised pipe already in the country's buildings. The alternative version of this set cuts NPT, the American taper, and the two are not interchangeable — the thread angles differ, and a joint made between the two forms will look tight and leak. If you are cutting threads that have to mate with locally bought fittings, BSPT is the one you want.

The taper matters too, and it is what makes pipe thread different from a bolt thread. A taper thread gets progressively thicker along its length, so as the joint is screwed up the threads wedge harder into one another and the metal itself makes the seal. That is why a pipe joint holds pressure at all, and why it is cut with a die rather than simply rolled.

The ratcheting handle is what makes the set usable in the real world. Threading a pipe requires a great many turns, and in a trench, against a wall, or between two other services there is very often no room to swing a handle through a full circle. A ratchet lets you work back and forth through whatever arc you have. It is aluminium, which keeps the weight of the assembly down when it is held out at the end of a length of pipe. The two extension bars slide into the handle to lengthen it, and on the larger 1" and 1-1/4" dies you will want them — cutting a full-size thread in steel by hand takes real leverage.

The buyers are plumbers and pipe fitters installing galvanised water line, irrigation and borehole installers, gas fitters, building services contractors, and factory and estate maintenance who have to make up pipework on site rather than buy it ready-threaded.

Three habits make the difference. Use cutting oil generously and keep using it through the cut — dry threading tears the thread face, blunts the die and produces a joint that will not seal however much tape you wrap on it. Start the die square to the pipe and check it after the first two turns, because a thread started crooked can never be corrected. And back the die off half a turn every turn or so to break the chip, rather than driving continuously. Ask on WhatsApp for a price on the set, and for cutting oil and a pipe vice if you are setting up from scratch.