BSPT TAPS BRITISH STANDARD PIPE TAPERED SUTTON

Sutton Tools manufactures high-quality British Standard Pipe Taper (BSPT) thread taps designed for both light-duty maintenance and heavy-duty industrial production.

• 1/8" (Nominal Pipe Size): This does not measure the actual physical outer diameter of the thread or the tap. It represents the standard nominal bore (inside diameter) of the pipe it is meant to fit. The actual outer diameter of a 1/8" BSPT male thread is roughly 9.73 mm (0.38 inches).
• 28 (Threads Per Inch / TPI): This is the thread pitch. It means there are exactly 28 individual thread crests per inch of thread length.
• BSPT (British Standard Pipe Taper): This indicates the thread profile and form. It features a 55° V-thread angle with rounded crests and roots. Crucially, the thread has a 1:16 taper (it gets progressively wider toward the back of the tap). This taper creates a mechanical, interference-fit seal when mated with a female fitting.

• Recommended Drill Bit Size: Use an 8.40 mm drill bit for a standard parallel hole before tapping.
• The Taper Factor: Because the hole is parallel but the tap is tapered, the tap has to work much harder as it goes deeper. For the best results and longest tool life, use a 1:16 taper pipe reamer after drilling but before tapping.
• Thread Sealant: Even though the tapered threads wedge together to block leaks, you must always use a thread sealant (like PTFE tape or pipe dope) during final assembly to fill minor microscopic voids.