1/8" NPT (National Pipe Taper) (1/8-27 NPT)
Where 1/8-27 NPT is used, its real dimensions, and how to connect it to other standards.
1/8-27 NPTThread standard
Designation1/8-27 NPT
Major diameter10.29 mm
Threads per inch / pitch27
Thread formtapered, 60 degree
Seals onon the thread flanks with PTFE tape
Used on: US gauge ports, small solenoid and instrument fittings.
The smallest common NPT at 27 TPI on a 0.405 inch outside diameter. NPT is 60 degree tapered and will not mate cleanly with the 55 degree BSP of the same size.
Quick-connect click fittings from Hozelock, Gardena and Karcher are proprietary and do not interchange. They all sit on top of a standard thread underneath, so the reliable way to move between brands is to adapt at the threaded tap or hose-end fitting, then use each brand's own connector above it.
Connect this thread
1/4" NPT (National Pipe Taper)related standard (1/4-18 NPT)3/8" NPT (National Pipe Taper)related standard (3/8-18 NPT)1/2" NPT (National Pipe Taper)related standard (1/2-14 NPT)3/4" NPT (National Pipe Taper)related standard (3/4-14 NPT)1" NPT (National Pipe Taper)related standard (1-11.5 NPT)
Sources: ANSI/ASME B1.20.1 (NPT pipe threads) · NPT thread dimensions chart (ASME B1.20.1), Machining Doctor