SHOWA Pipe Tap

Pipe taps are used to cut internal threads in pipes or fittings so they can accept threaded pipe connections. Unlike standard thread taps, pipe taps cut threads that are tapered or parallel, ensuring a tight fit for sealing under pressure.

1. NPT (National Pipe Taper) Tap

• Standard: American (ANSI/ASME B1.20.1).

• Thread: Tapered (1°47′ per side, ~1 in 16 taper).

• Seal: Achieved by metal-to-metal interference as the tapered threads tighten.

• Use: Common in the USA for air, gas, and liquid piping.

2. BSPT (British Standard Pipe Taper) Tap

• Standard: ISO 7-1 (also known as R thread).

• Thread: Tapered, similar to NPT but with a 55° thread angle (NPT uses 60°).

• Seal: Thread interference (like NPT), often with sealant or PTFE tape.

• Use: Widely used in UK, Europe, and Asia for fluid & gas lines.

3. BSPP (British Standard Pipe Parallel) Tap

(often just called BSP in general use)

• Standard: ISO 228-1 (also known as G thread).

• Thread: Parallel (straight) threads, not tapered.

• Seal: Requires a washer, O-ring, or gasket to make a pressure-tight joint.

• Use: Hydraulic systems, plumbing, sealing with flat seats.

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