STAINLESS STEEL PIPE NUTS DIN 431

Pipe Nuts DIN 431 — A pipe nut is a different type of fitting from the plugs above it in this range: rather than blanking a threaded port from inside, it's a separate coupling piece sized and threaded to run onto the external (male) thread on the end of a pipe, used either to join two pipe-threaded fittings together or to cap an open pipe end on its own. DIN 431 pipe nuts are matched to BSP (British Standard Pipe) thread form as standard, the same thread family used across the DIN 906, 908, and 910 plug range, so compatibility with pipework elsewhere in a system follows normal BSP sizing conventions rather than needing a separate thread standard to track. Installation is straightforward: the nut is screwed onto the pipe's external thread using a spanner on its hex or flatted body, with thread sealant or PTFE tape applied as required for the fluid and pressure involved, exactly as with any threaded pipe joint. Typical uses span plumbing, pneumatic and low-pressure fluid systems, and general pipework assembly wherever two threaded pipe ends need to be joined, or a single open pipe end needs capping without the pipe itself having an internal port to plug. Choosing the right pipe nut comes down to matching thread size and form precisely to the pipe being fitted - using a nut sized for the wrong BSP designation will either not engage properly or won't seal even with tape or sealant applied. Grade selection follows the same reasoning as the plug range: A2 is generally adequate for indoor plumbing and general low-corrosion fluid work, while A4 is worth the extra cost in washdown environments, marine or coastal pipework, food and beverage processing, or chemical-adjacent systems, where chloride exposure would otherwise shorten an A2 fitting's service life.

FAQs
Does a pipe nut need a mating fitting, or can it work alone?
It can be used alone to cap an open pipe end, or paired with another threaded fitting or a second pipe nut to join two lengths together - its role depends on what's on the other side of the joint.

What tool is needed to tighten a pipe nut?
A standard spanner on the hex or flatted body; no special socket or Allen key is needed, unlike the socket-drive pipe plugs elsewhere in this range.

Is BSP the only thread form available for this fitting?
BSP is the standard thread form for DIN 431; if a system uses a different thread standard (such as NPT), it's worth confirming compatibility before ordering rather than assuming interchangeability.