A special BSPT tap is a custom-built tap that cuts British Standard Pipe Taper threads to a specification a catalog tap can’t meet, whether that’s an unusual size, a difficult material, or a demanding production run. Taylor Tool, a Canadian tap manufacturer since 1918, builds special taps from your drawing or sample. This guide covers when you need one, which specs to define, and how to avoid common tapping problems.

What Are Special BSPT Taps?

BSPT (British Standard Pipe Taper) taps cut tapered pipe threads that seal as the male and female threads wedge together; “special” means the tap is made to a custom specification rather than pulled from stock. BSPT is a Whitworth-based form with a 55 degree thread angle (a general industry specification, not a Taylor Tool claim).

The difference between taper and parallel threads is simple. A parallel thread keeps the same diameter along its length, so it relies on a washer, O-ring or bonded seal to stop leaks. A tapered pipe thread narrows along its length, so the mating threads tighten against each other and form the seal in the threads themselves. That’s why pipe taps like the BSPT taper tap have to control both pitch and taper, not just diameter.

If your part calls for an unusual form beyond BSPT, see our overview of special thread taps for the wider range of custom thread forms we manufacture.

When a Standard BSPT Tap Isn’t Enough

A standard BSPT tap falls short when your job involves unusual sizes, difficult materials, challenging hole types, or production volumes that wear out a catalog tap too quickly. In those cases, a special tap built around your application lowers cost per hole and improves thread consistency.

Common triggers include:

• Non-stock sizes: Oversized, large-diameter or unusual-pitch tapered threads that distributors don’t carry.
• Hard or abrasive materials: Hardened steels or high-silicon aluminum, where high-speed steel loses its edge quickly.
• Blind holes: Where chip evacuation and thread depth near the bottom of the hole need a purpose-built geometry.
• High-volume runs: Where tool life and repeatability drive your economics.
• Left-hand or multi-lead requirements: Forms that general suppliers rarely stock.

Taylor Tool designs and produces special taps from a customer’s drawing or sample, so you aren’t forced into an off-the-shelf compromise. For a broader look at purpose-built tooling, see our special purpose taps.

BSPT vs BSPP vs NPT: Key Differences

BSPT is a tapered, 55 degree Whitworth-based pipe thread; BSPP is its parallel counterpart; and NPT is a tapered American form with a different thread angle. All three are “pipe threads,” but they are not the same and should not be mixed.

What is the difference between BSPT and NPT? The thread angle (55° vs 60°) and pitch conventions differ, even though both taper. What is the difference between BSPT and BSPP? BSPT tapers and seals on the threads; BSPP runs parallel and needs a separate seal.

The pitfall: BSP and NPT are not interchangeable. Forcing one into the other can leave a partial thread engagement that leaks or galls. Taylor Tool also manufactures BSPP, Whitworth and PG taps, so you can source related forms from one manufacturer.

Specifications to Define Before You Order

To order a custom BSPT tap, define the thread size, threads per inch (pitch), taper requirement, workpiece material, hole type and tolerance, and send a drawing or sample if you have one. The more complete the spec, the faster the tap gets made right.

What information do I need to order a custom BSPT tap? Use this checklist:

• Thread size and form: Nominal pipe size and confirmation that it’s BSPT.
• Threads per inch / pitch: Stated explicitly, especially for non-standard sizes.
• Hand: Right-hand or left-hand thread.
• Flute style: Spiral point, spiral flute or other (see below).
• Substrate: HSS, carbide or powdered metal.
• Workpiece material: Steel, stainless, aluminum, alloy, composite.
• Hole type: Blind hole or through hole, and required thread depth.
• Tolerance and gauging requirements: As called out on your print.
• Volume and application: One-off prototype or repeat production.

Whenever possible, supply a drawing or a sample part. Taylor Tool’s engineering team works directly from either to deliver a tap suited to your application. Ask about tolerance classes and delivery timing for your specific order.

Choosing Flute Style, Material and Substrate

Match tap geometry to the hole type and workpiece: spiral point taps for through holes, spiral flute taps for blind holes and stainless, and carbide or powdered metal substrates when the material is hard, abrasive or the volume is high.

• Spiral point taps push chips forward, which suits through holes.
• Spiral flute taps pull chips up and out, which suits blind holes and stainless steel. Which tap style is best for blind holes in BSPT? A spiral flute tap, because it evacuates chips back out of the hole.
• HSS taps are the general-purpose choice for most materials.
• Carbide taps deliver wear resistance and rigidity in hardened steels and abrasive materials. Can BSPT taps be made in carbide? Taylor Tool manufactures carbide and carbide-tipped taps; ask about availability for your specific BSPT size.
• Powdered metal taps offer an exceptionally uniform, tough substrate for heavy machining.

For demanding production environments, explore our high performance spiral taps, engineered for higher speeds, longer tool life and lower cost per hole.

Common BSPT Tapping Problems and Fixes

Most BSPT tapping problems trace back to the wrong drill size, insufficient attention to taper depth, or poor chip evacuation. Fixing those three areas resolves the majority of issues.

• Oversized or undersized threads: Check the pre-tap hole size and confirm the tap is advanced to the correct taper depth. Gauge the thread against your print rather than relying on feel.
• Tap breakage: Often caused by a hole that’s too small, chips packing in the flutes, or misalignment. Verify drill size, improve chip clearance and check machine alignment.
• Poor chip flow: Switch flute style, using spiral point for through holes and spiral flute for blind holes, and confirm coolant reaches the cut.
• Short tool life: Consider a different substrate, such as carbide for abrasive material, or a coating suited to the workpiece.

What drill size do I need before tapping BSPT? It depends on the pipe size and thread tolerance, so confirm against a BSPT tap-drill chart or ask us for guidance on your specification. For our broader tap range, see our taps overview.

Custom BSPT Taps from Taylor Tool

Taylor Tool is a Canadian manufacturer, established in 1918 and based in Cambridge, Ontario, that builds special taps to your drawing or sample. Because we manufacture rather than resell, we control quality from start to finish.

For production-critical needs, we offer 24-hour jet-tap service. We supply automotive, aerospace, power generation and general manufacturing customers, from small job shops to the largest industrial manufacturers. Does Taylor Tool make BSPT taps to custom specifications? Yes. Our engineering team works with you whether you need a modified standard or a completely unique tool.

Ready to start? Contact Taylor Tool or request a quote with your drawing, sample or spec list.

Frequently Asked Questions

What is a BSPT tap?

A BSPT tap cuts British Standard Pipe Taper threads, which narrow along their length so mating parts seal against each other. It’s used for pipe fittings and connections that must hold pressure without a separate gasket.

What is the difference between BSPT and NPT taps?

BSPT taps cut a 55° Whitworth-based taper, while NPT taps cut a 60° American taper. Both are tapered, but the thread angle and pitch conventions differ, so the taps are not interchangeable.

What is the difference between BSPT and BSPP?

BSPT is tapered and seals on the threads; BSPP is parallel and relies on a washer, O-ring or bonded seal. Both share the 55° Whitworth-based thread form.

What is a special BSPT tap?

A special BSPT tap is made to a custom specification, such as an unusual size, material, flute style or tolerance, rather than being a standard catalog item.

Can BSPT taps be made in carbide?

Taylor Tool produces carbide and carbide-tipped taps for hard and abrasive materials. Ask our team about carbide for your specific BSPT size and application.

What drill size do I need before tapping BSPT?

It depends on the nominal pipe size and thread tolerance. Check a BSPT tap-drill chart or contact us with your specification for guidance.

Are BSPT and NPT threads interchangeable?

No. The thread angle and pitch differ, so mixing them can cause poor engagement, leaks or galling. Always match the tap to the mating thread standard.

What information do I need to order a custom BSPT tap?

Provide thread size, pitch, hand, flute style, substrate, workpiece material, hole type and tolerance, plus a drawing or sample if available.

Which tap style is best for blind holes in BSPT?

A spiral flute tap, because it pulls chips up and out of the hole, which helps prevent packing and tap breakage.

Does Taylor Tool make BSPT taps to custom specifications?

Yes. Taylor Tool designs and manufactures special taps from your drawing or sample, including BSPT and other specialty thread forms.

How do I order special taps from Taylor Tool in Canada?

Taylor Tool sells through a network of Canadian distributors. Contact our sales team and we’ll connect you with your nearest authorized distributor for pricing and availability.

Does Taylor Tool ship to the United States?

Yes. Taylor Tool is expanding its U.S. sales network. Contact our sales team directly for U.S. ordering information, lead times and distributor availability in your region.