Dies
A die cuts or restores an external thread — the male counterpart to a tap. A special die is one made to a specification no catalog carries: a non-standard diameter or pitch, an unusual thread form, a left-hand thread, a particular outside diameter to suit your die stock, or a tolerance tighter than commercial classes allow. WESTport manufactures threading dies to your blueprint or from a sample part in round adjustable split, hexagon, hexagon rethreading and cone styles, across Unified, metric, ACME and pipe thread forms, in right or left hand, in High-Speed Steel or CBN. We hold one of the industry's largest inventories of die blanks, which is where our turnaround on custom specials comes from. Made in the USA and supplying precision manufacturing since 1989.
The WESTport die line
Every die below is built to order. Send a print, a sample, or the thread callout and application, and we will quote the tool that fits it.
- Round Adjustable Split Dies. The workhorse. A radial split and adjusting screws let the die be expanded or contracted slightly, so one tool can be tuned for class of fit, compensated as it wears, or set to hit a specific tolerance. Available in outside diameters from 13/16″ through 2 1/2″ and larger, in HSS or CBN, in Unified, metric, ACME, left-hand and specialty forms.
- Round Adjustable Split Pipe Dies. The same adjustable split construction cut for tapered and straight pipe threads — NPT, NPTF, BSPT, BSPP, ANPT and NPSM — where the ability to fine-tune thread fit matters for sealing. HSS or CBN, in 1″ through 3″+ outside diameters.
- Hexagon Pipe Dies. A six-sided body that drives from a standard die stock, an adjustable wrench or a socket, which is what makes it the field and maintenance tool of choice for cutting and restoring external pipe threads away from a machine. NPT and NPS in common pipe sizes.
- Hexagon Rethreading Dies. Purpose-built for chasing and restoring damaged external threads rather than cutting new ones — the tool you reach for on a burred stud or a fastener that has been dropped. Available in HSS and CBN across a wide size range, specified by thread size and distance across flats.
- Cone Dies. Also called acorn, spring or taper nose dies. The tapered nose projects beyond the die holder, closing the distance between the cutting edges and a shoulder — so you can thread far closer to an obstruction than a conventional round die allows. HSS and premium tool steel, in Unified, metric, ACME, left-hand and specialty forms.
- Popular Special Dies — Inches. The non-standard inch sizes customers ask for most often, held ready in blank form: #5-40 upward in round adjustable split style, in 13/16″, 1″, 1 1/2″ and 2″ outside diameters, right hand and left hand, including NPT.
- Popular Special Dies — Metrics. The equivalent metric range from M8 upward in round adjustable split style, in 1″, 1 1/2″ and 2″ outside diameters, right hand and left hand.
What we make dies for
Choosing a die style
The choice comes down to three questions: are you cutting a new thread or restoring an old one, do you need to adjust the fit, and is there an obstruction near the thread.
| Style | Adjustable | Best for | Driven by |
|---|---|---|---|
| Round adjustable split | Yes | Cutting new threads to a specific class of fit; production and tool room | Die stock |
| Hexagon | No | Cutting and restoring pipe threads in the field | Die stock, wrench or socket |
| Hexagon rethreading | No | Chasing and repairing damaged existing threads | Die stock, wrench or socket |
| Cone (acorn) | No | Threading close up to a shoulder or obstruction | Cone die holder |
HSS or CBN
Most dies are ground from High-Speed Steel, which handles the great majority of workpiece materials and is the economical choice for general production and repair. CBN is offered on round adjustable split dies, split pipe dies and hexagon rethreading dies, where its hardness pays for itself on abrasive or hardened materials and in high-volume runs that would wear an HSS die quickly. Both carry the same thread geometry — specify the material with the order, along with hand, outside diameter and tolerance class.
Industries served
Energy & Oil and Gas
Pipe dies for wellhead, pressure and pipeline work, including field repair of threads that cannot be brought back to a shop.
Aerospace & Defense
ANPT pipe dies and close-tolerance specials where thread class is controlled and documented.
Fluid Power & Plumbing
NPT and BSPT dies for producing and restoring sealing threads on fittings, ports and connectors.
Automotive & Heavy Equipment
Rethreading dies for studs, shafts and fasteners, and ACME dies for lead screw and actuator work.
Job Shops, MRO & Tool Rooms
One-off specials made from a worn die or a sample part when the size was never standard or the original source is gone.
Why WESTport
- One of the industry's largest die blank inventories. Most specials start from a blank already on our shelf, not from bar stock — which is where the turnaround advantage comes from.
- Blueprint, sample or callout. Send a print, mail us the worn die, or just give us the thread and the application. We reverse-engineer specials routinely.
- Right hand and left hand, every form. Unified, metric, ACME, pipe and proprietary geometries, in the outside diameter your die stock takes.
- Matched taps and dies from one source. Internal and external tooling for the same thread, cut to the same specification, quoted together.
- Made in the USA, supplying precision manufacturing since 1989.
| PART# | PRODUCT NAME | SIZE | TPI | PRICE | SALE PRICE |
