A rolled thread is stronger than a cut one of the same size, and the reason is structural rather than marketing: the grain is displaced around the root instead of being severed, and the root itself ends up in compression. Fatigue failures in threaded parts almost always start at the thread root, which is why rolling is specified on anything that will see cyclic load. It is also faster than cutting and produces no swarf. The blank must be made to the pitch diameter, not the major diameter — a detail that surprises people the first time they reverse-engineer a rolled part.
What Thread Rolling is the right choice for
- Any thread that will carry fatigue or cyclic load
- High volumes — rolling is much faster than cutting
- Ductile materials that displace cleanly
Where it is the wrong choice
- Not practical on hardened material — the thread is rolled before heat treatment
- Internal threads cannot be rolled this way (see tapping)
- Interrupted or partial-length threads need care at the run-out
Parts produced this way
- Custom Bolt — 75 standard parts in the catalog
- Custom Screw — 114 standard parts in the catalog
- Custom Anchor & Concrete Fixing — 29 standard parts in the catalog
Usually combined with
Thread Rolling is rarely the only operation on a part. On most jobs it sits in a sequence with:
Order terms
- Minimum order
- 2,000–5,000 pieces. The exact figure depends on the part: it is set by the tooling the drawing calls for, and is confirmed when the drawing has been reviewed.
- Samples
- Within 7 days of drawing approval.
- Drawing
- Preferred, but not required — a sample, photographs or a sketch is enough to start.
What a quotation needs
Nine things, and a drawing settles most of them at once. Where a field is unknown, say so — an assumption stated is better than a blank, and several of these can be recommended rather than specified.
- Drawing
- A 2D drawing (PDF or DWG) or a 3D model settles almost every other question on this list at once.
- Dimensions
- Diameter, length, head size and any features — enough to know what is being made.
- Tolerance
- Tolerance is the single biggest cost driver. Tell us which dimensions are critical and which are not — holding everything tight costs money on features nobody measures.
- Material
- Carbon steel, alloy steel, stainless, brass, aluminium, titanium — or the application, and we will suggest one.
- Strength grade
- Property class to ISO 898-1 (8.8, 10.9, 12.9) or stainless class to ISO 3506 (A2-70, A4-80). This decides the material and the heat treatment together.
- Thread standard
- Metric coarse, metric fine, UNC, UNF, BSW or a pipe thread — and the tolerance class if it is specified.
- Surface finish
- Zinc, hot-dip galvanised, black oxide, Dacromet, Geomet, nickel, passivation, or plain. Salt-spray hours if you have a requirement.
- Quantity
- Annual volume and first-order quantity. Volume changes which process is the right one, so it changes the price more than most buyers expect.
- Application & environment
- What the part holds together, and what it has to survive — temperature, vibration, chemicals, salt. This is what lets us catch a specification that will not work before it is made.
Questions
What is the minimum order quantity for a custom part?
Between 2,000 and 5,000 pieces for most parts. The exact figure depends on the part: it is set by the tooling the drawing calls for, and is confirmed when the drawing has been reviewed.
How long does a sample take?
Within 7 days once the drawing has been approved. The drawing stage comes first, and for a part being reverse-engineered from a sample it is where most of the time goes.
Can you make a part without a drawing?
Yes. A physical sample, photographs against a scale, or a dimensioned sketch are all workable starting points. A drawing is produced from whichever of those you have and sent back for approval before anything is made.
When is Thread Rolling not the right process?
Not practical on hardened material — the thread is rolled before heat treatment. Internal threads cannot be rolled this way (see tapping). Interrupted or partial-length threads need care at the run-out.
Which fasteners are made by thread rolling?
In this catalog: bolt, screw, anchor & concrete fixing. Whether it is the right process for a particular part depends on the drawing and the quantity.
Send the part
A drawing answers most of this at once. If you do not have one, fill in what you know and attach a photograph — samples follow within 7 days of the drawing being approved.