A special BSPT die cuts an external British Standard Pipe Taper thread to a size, form, material or tolerance that falls outside standard catalogue tooling. When a stock die can’t match your drawing, a custom-built die lets you cut tapered pipe threads that seal correctly and repeat reliably. Taylor Tool, a Canadian manufacturer based in Cambridge, Ontario, designs and manufactures custom cutting tools to your specification; contact the sales team to discuss your BSPT requirements.
What Are Special BSPT Dies?
BSPT (British Standard Pipe Taper) dies cut external tapered pipe threads, and “special” means the die is built to a non-stock size, thread form, material or tolerance. Standard catalogue dies cover common sizes and conventional specifications; a special die is made when your part doesn’t fit those boxes.
BSPT threads follow a 55 degree thread angle and a 1:16 taper (these are general standard figures, commonly associated with ISO 7-1 and BS 21). That taper is what lets the mating threads wedge together and seal. When your application demands something beyond a stock offering, such as an unusual diameter, a different hand or a tuned geometry for production, custom tooling is the practical route. Taylor Tool’s custom thread cutting dies are manufactured in Canada to exacting specifications.
BSPT vs BSPP: Tapered vs Parallel Pipe Threads
BSPT threads taper and seal on the thread itself, while BSPP threads are parallel and typically rely on a washer, O-ring or sealing compound to seal. That single difference drives how the die is designed and how the fitting performs.
| Feature | BSPT (tapered) | BSPP (parallel) |
|---|---|---|
| Thread profile | Tapered, 1:16 taper | Straight, no taper |
| Thread angle | 55 degrees | 55 degrees |
| Sealing method | Thread-on-thread, often with sealant | Washer, O-ring or sealant at a face |
| Typical use | Pipe fittings, fluid and gas connections | Hydraulic fittings, ports, general plumbing |
| Die implication | Die must cut a progressively changing diameter | Die cuts a constant diameter |
Also worth knowing: BSPT and NPT are not interchangeable. Both are tapered, but they differ in thread angle (55 degrees versus 60 degrees) and pitch for many sizes, so mixing them risks leaks and damaged threads. Taylor Tool also produces BSPP and Whitworth tooling, so you can source related British thread forms from one manufacturer.
When You Need a Special BSPT Die Instead of a Standard One
You need a special BSPT die when your thread size, length, lead, material or tolerance falls outside what stock catalogue tooling covers. If a standard die can’t produce a conforming thread on your workpiece, it’s time to specify one.
Common situations include:
- Unusual diameters or lengths that don’t match standard BSPT sizes.
- Production runs where you want geometry tuned for speed, finish or tool life.
- Hard-to-cut workpiece materials that demand a specific die material or design.
- Non-standard tolerances that stock tooling can’t hold.
Taylor Tool works from your drawing or sample, so you don’t need a finished specification sheet to start the conversation.
Key Specifications to Define Before You Order
Define the thread size, taper, pitch (TPI), hand, workpiece material and die style before you request a quote. Having these ready shortens the back-and-forth and reduces the risk of ordering the wrong tool.
Use this as a quote-request checklist:
| Specification | What to provide |
|---|---|
| Thread size | Nominal pipe size or major diameter |
| Thread form and standard | BSPT, with the governing standard (for example ISO 7-1 or BS 21) |
| Taper | Confirm 1:16 or note any deviation |
| Pitch / TPI | Threads per inch for your size |
| Hand | Right-hand or left-hand |
| Workpiece material | Steel, stainless, brass, aluminum, etc. |
| Die style | Your preferred style, or ask the sales team to recommend one |
| Tolerance and gauging | Class or acceptance requirements |
| Quantity | One-off, prototype or repeat production |
| Drawing or sample | Attach whichever you have |
Don’t assume tolerances. Confirm the applicable standard and any class requirements with Taylor Tool’s engineering team so the die matches your inspection method.
Die Styles and Materials for BSPT Threading
Choose die style by machine setup and production volume, and choose die material by the workpiece you’re threading. The right pairing improves thread quality and extends tool life.
Die style is typically chosen to suit your machine setup, your production volume and how you plan to gauge the thread. Some designs favour rigid, repeatable performance on high-volume work, while others allow small size adjustments to compensate for wear or fine-tune fit. Discuss your setup with the sales team to determine which style suits your job.
Die material depends on what you’re cutting. High-speed steel is a common choice for general work, but harder or more abrasive workpieces may call for other options. The best choice depends on the workpiece and production volume, so discuss your application with the sales team.
Custom BSPT Dies from Taylor Tool
Taylor Tool, a Canadian manufacturer since 1918, designs and manufactures custom dies, taps and reamers to your specification. Specialty thread forms such as Acme, buttress, Whitworth and BSPP are among the tooling the company produces; contact the sales team to discuss your BSPT requirements.
As a manufacturer rather than a reseller, Taylor Tool controls quality from design through production and supplies customers from small job shops to the largest industrial manufacturers in automotive, aerospace, power generation and general manufacturing. Our engineering team works with you to deliver a modified standard or a completely unique tool.
In Canada, products are sold through an established distribution network, and sales associates can direct you to your nearest distributor. Taylor Tool is also expanding its U.S. representation, so contact the sales team for U.S. ordering information. For the matching internal thread, see our special thread taps.
Pairing BSPT Dies with Taps and Custom Sets
Mating internal and external threads are best specified together so the fit, taper and tolerance work as a system. Ordering the die and tap against the same drawing avoids mismatches at assembly.
Pair your external die with the corresponding internal tool from our range of special purpose taps, and ask the sales team how to coordinate the two against the same drawing. If you’re exploring related British and pipe thread tooling, look for our posts on special pipe dies and special Whitworth dies, which cover neighbouring thread forms in more depth.
How to Request a Quote
Send your drawing or sample along with the thread size, taper, material and quantity, and Taylor Tool will respond with options. The more detail you include from the checklist above, the faster the process.
- Email: sales@taylortool.com
- Phone (Canada): 1-800-265-2145
- Phone (USA): 1-855-221-8277
- Local: 519-658-9378
- Address: 4 Goebel Avenue, Cambridge, ON N3C 1Z1
Visit the contact page to send a message or request a quote online.
Frequently Asked Questions
What is a BSPT die?
A BSPT die is a threading tool that cuts external British Standard Pipe Taper threads. It produces a thread with a 55 degree angle and a 1:16 taper, allowing a tight, sealing fit with a mating internal BSPT thread on pipe fittings and similar parts.
What is the difference between BSPT and BSPP threads?
BSPT threads taper and seal on the thread itself. BSPP threads are parallel and generally need a washer, O-ring or sealant to seal. Both use a 55 degree thread angle, but the die for each is designed differently because of the taper.
What is the taper on a BSPT thread?
The standard taper is 1:16 on diameter, with a 55 degree thread angle. These are general standard figures associated with ISO 7-1 and BS 21. Confirm the governing standard and any tolerance class with the engineering team for your application.
Can BSPT dies be made to a custom size or specification?
Yes. Taylor Tool specializes in custom cutting tools and works from your drawing or sample. Whether you need a modified standard or a completely unique tool, the engineering team works with you to deliver the right solution for your machining requirements.
What is the difference between adjustable and solid threading dies?
The right die style depends on your machine setup, production volume and gauging needs. Some designs are rigid and suited to repeatable production, while others allow small size changes to compensate for wear or fine-tune fit. Talk with the Taylor Tool sales team about which approach suits your application.
What information do I need to order a special BSPT die?
Provide the thread size, taper, pitch or TPI, hand, workpiece material, die style, tolerance requirements and quantity, plus a drawing or sample. The specification checklist in this article covers everything the team typically needs to quote accurately.
Are BSPT and NPT threads interchangeable?
No. Both are tapered, but BSPT uses a 55 degree thread angle while NPT uses 60 degrees, and pitches differ for many sizes. Mixing them risks leaks and thread damage, so match each fitting to its correct standard.
What materials can BSPT dies cut?
It depends on the die material and design. Dies are generally selected to suit the workpiece, whether steel, stainless, brass or aluminum. Discuss your specific application and production volume with Taylor Tool.
Do I need a matching tap for a BSPT die?
If you’re producing both internal and external threads, yes, it’s best to specify them together. A matching tap cuts the internal BSPT thread that mates with your die-cut external thread, ensuring consistent fit and sealing performance.
Does Taylor Tool manufacture special dies in Canada?
Yes. Taylor Tool is a Canadian manufacturer, established in 1918 and based in Cambridge, Ontario. It designs and manufactures special taps, reamers and dies, with all products made in Canada to exacting specifications.
Can Taylor Tool supply special dies to the United States?
Yes. Taylor Tool is actively expanding its U.S. distribution network. Contact the sales team at 1-855-221-8277 for U.S. ordering information, lead times and distributor availability in your region.
Can a worn BSPT die be rethreaded or replaced?
Rethreading dies are generally used to clean up or restore damaged existing threads, and a die that has worn out of tolerance may need to be replaced. Contact Taylor Tool with your drawing or sample to discuss a custom die built to your specification.