Connect M22 x 1.5 pressure-washer, 15 mm bore to 3/8" NPT (National Pipe Taper)
How to join M22 x 1.5 (15 mm) and 3/8-18 NPT, and what stops it leaking.
Needs adapter
End A
M22 x 1.5 pressure-washer, 15 mm bore (M22 x 1.5 (15 mm))
Seals on O-ring on the 15 mm spigot
via adapter
End B
3/8" NPT (National Pipe Taper) (3/8-18 NPT)
Seals on on the thread flanks with PTFE tape
Adapter neededM22 to 3/8 NPT pressure-washer adapter
Not a direct fit. Joining M22 x 1.5 pressure-washer, 15 mm bore to 3/8" NPT (National Pipe Taper) needs a M22 to 3/8 NPT pressure-washer adapter.
The adapter to buy
Search Amazon for M22 to 3/8 NPT pressure-washer adapteraffiliate searchFind M22 to 3/8 NPT pressure-washer adapter on eBayaffiliate
US pressure-washer pumps often carry 3/8 NPT ports, so an M22-to-3/8-NPT adapter joins a metric M22 lance or hose to the pump. The NPT end seals on the tapered thread with PTFE tape; the M22 end seals on its O-ring.
Tape only the NPT end. The M22 O-ring end must stay clean or it will leak despite the tape.
Related connections
M22 x 1.5 pressure-washer, 15 mm boreM22 x 1.5 (15 mm)3/8" NPT (National Pipe Taper)3/8-18 NPTM22 x 1.5 pressure-washer, 14 mm bore to M22 x 1.5 pressure-washer, 15 mm boreadapterM22 x 1.5 pressure-washer, 15 mm bore to Garden Hose Thread (GHT / NH)adapterM22 x 1.5 pressure-washer, 15 mm bore to 3/4" BSP parallel (G3/4 / BSPP)adapter
Sources: Pressure-washer M22 14mm vs 15mm fitting data (M MINGLE spec) · ANSI/ASME B1.20.1 (NPT pipe threads) · NPT thread dimensions chart (ASME B1.20.1), Machining Doctor