Almost every rivet you will ever buy is cold formed, not cut. A coil of wire is drawn to size, sheared into a slug, and struck two to five times inside hardened dies until the head appears. No furnace, no chips, no cutting tool touching the head.
That one fact explains nearly everything a buyer cares about downstream: why rivets get cheap fast in volume, why a cold-formed rivet is stronger than a machined one of the same alloy, why some head shapes cost double, and why the length tolerance on your drawing will always be looser than the diameter tolerance unless you pay for a secondary operation.
This guide walks the full production route as it actually runs on a fastener floor, then gives you the material grades, the tolerance bands, and the design rules that decide your unit price.
How Are Rivets Made? The Short Answer
Rivets are made by cold heading, a room-temperature forging process. The sequence is:
- Wire selection — cold heading quality (CHQ) wire in the specified alloy, supplied on coil with a mill certificate.
- Drawing and lubrication — the wire is pulled through dies to exact diameter, then pickled and phosphate-coated so it can flow through tooling without galling.
- Cutoff — a shear cuts a slug of precisely metered volume. Slug volume determines whether the head fills.
- Heading — punches drive the slug into progressive die cavities. Two to five blows form the head and shank.
- Piercing or extrusion — for semi-tubular, tubular, and blind rivets, the shank hole is punched or back-extruded in-station.
- Secondary operations — knurling, trimming, drilling, threading, or CNC turning where the geometry or tolerance exceeds what heading alone can hold.
- Heat treatment — only for steel grades that need a specified hardness or core strength.
- Deburring and cleaning — vibratory tumbling removes the shear burr and cutoff witness mark.
- Surface finishing — zinc, nickel, tin, or chemical passivation, with a hydrogen embrittlement relief bake on hardened plated parts.
- Inspection, sorting, packing — gauge checks, optical or eddy-current sorting, then bulk or tray packaging.
A multi-station header running small rivets typically produces 100 to 300 pieces per minute. That throughput, not the material cost, is why rivets are priced in fractions of a cent at volume.
Why Cold Forming, Not Machining
This is the mental model worth keeping. A machined rivet is made by removing metal until only the rivet is left. A cold-formed rivet is made by pushing metal until it becomes the rivet. Three consequences follow.
Grain flow follows the shape. When steel is cut, the grain structure is sliced across; the head-to-shank corner becomes a stress riser with severed grain. When it is upset, the grain bends around the corner and stays continuous. That is the physical reason a cold-headed head resists popping off under a bucking bar or an orbital riveting head, and why aerospace and automotive specs call for formed heads rather than turned ones.
Almost nothing is thrown away. Heading is a near-net-shape process, so the only scrap is the cutoff burr and the trim slug on a hex or square head. Round wire also runs roughly 30% cheaper than bar stock before you account for the chips a lathe would make[citation].
Speed is the pricing lever. A CNC lathe makes one rivet per cycle. A four-die header makes one per stroke, several hundred times a minute. Below a few thousand pieces the tooling amortization dominates and turning can win. Above that, heading wins by an order of magnitude, and the gap widens with quantity.
The trade is flexibility. A lathe will make whatever the drawing says. A header will only make what the metal can be persuaded to flow into, which is why the design rules further down matter more than most buyers expect.
The Production Process, Station by Station
1. Wire Selection and Incoming Control
Rivet quality is decided before the wire reaches the machine. The feedstock must be cold heading quality — a designation covering chemistry consistency, surface freedom from seams and laps, and a microstructure that will deform without cracking. A general-purpose wire of the same nominal grade will head for a while and then start splitting heads at random, usually after the die is already worn in.
For traceable programs, the coil arrives with a mill certificate stating heat number, chemical analysis, and mechanical properties. Automotive and electrical customers frequently require that certificate to follow the shipment.
2. Drawing, Annealing, and Lubricant Carrier
The coil is drawn down through carbide dies to the exact diameter the die set expects. Drawing work-hardens the wire, so higher-carbon steels and some stainless grades get a spheroidize anneal to restore formability, then a pickle to strip scale.
The step most buyers have never heard of matters most: the wire is coated with a zinc phosphate layer carrying a soap lubricant. Metal being extruded through a die at forming pressure will otherwise weld itself to the tooling. Poor lubricant carrier is the single most common cause of scored shanks and short die life.
3. Cutoff and Slug Volume
The wire feeds in, a shear cuts a slug, and a transfer finger moves it to the first die. Slug volume is the hidden variable behind head quality. Too little and the head cavity under-fills, giving a rounded or short head. Too much and the excess flashes out at the parting line. Because slug volume is set by feed length, and feed length drifts as the shear blade wears, cutoff variation is the largest single contributor to overall length tolerance.
4. Multi-Station Heading
The heart of the operation. Machines are described by die and blow count — 2-die 3-blow, 3-die 4-blow, 4-die 4-blow, and up. Each station does one thing: cone the slug, form the head, extrude the shank, pierce, trim.
There is a hard physical limit here worth memorizing. In a single blow, the unsupported length of wire being upset should not exceed roughly 2.3 times the wire diameter. Push past it and the slug buckles sideways instead of spreading, producing folds and cold shuts. A large head on a thin shank is therefore not a drawing decision, it is a station-count decision: coning it in an intermediate cavity first lets you upset far more material, but it consumes a station and a die.
This is why two rivets that look almost identical can quote 40% apart.
5. Hole Forming for Tubular and Semi-Tubular Rivets
Semi-tubular and tubular rivets are not drilled. The hole is punched or back-extruded in the header while the part is still in the die, which keeps the hole concentric with the shank and adds no cycle time.
The distinction is dimensional: a semi-tubular rivet has a hole depth not exceeding 112% of the shank diameter, leaving a solid section that carries shear load. A full tubular rivet is hollow through most or all of its length and is used where the joint needs to swivel or pass a wire, at the cost of shear strength. YIWAN’s stainless steel semi-tubular rivets are formed this way.
Blind rivets add an assembly step: the body is headed and pierced, the mandrel is headed separately, then the two are mechanically married and the mandrel head is seated into the body.
6. Secondary Operations
Heading gets you most of the way. Anything it cannot reach happens after:
- Knurling for press-fit retention in plastic or die-cast housings
- Trimming for hex, square, or shaved heads
- Thread rolling on hybrid screw-rivet parts, which is again a forming process, not a cutting one
- Drilling and reaming where hole tolerance is tighter than punching can hold
- CNC turning for undercuts, tapers, cross-holes, or diameter tolerances below what the die will give
Each secondary operation adds handling, scrap risk, and price. A part that ships straight off the header is always the cheapest part on the quote sheet.
7. Heat Treatment
Aluminum, copper, brass, and most austenitic stainless rivets skip this. Carbon and alloy steel rivets get heat treated only when the print specifies a hardness or a load rating: quench and temper for core strength, carbonitriding for a hard case with a tough core.
Heat treatment is not free insurance. Over-hardening a rivet makes it crack when it is set rather than deform into a shop head, which is exactly the opposite of what a rivet needs to do.
8. Deburring, Cleaning, and Finishing
Vibratory tumbling with ceramic or plastic media knocks off the shear burr and the cutoff witness mark. Then finishing, chosen by environment rather than by appearance:
| Finish | Typical use | Notes |
|---|---|---|
| Clear / blue zinc | Indoor, general industrial | Lowest cost corrosion barrier |
| Yellow / black zinc | Outdoor, automotive underhood | Chromate conversion adds hours of protection |
| Zinc-nickel | Harsh or coastal | Substantially better salt spray than plain zinc |
| Nickel plating | Decorative and electrical | Good conductivity and appearance |
| Tin plating | Electrical contacts, solderability | Common on copper rivets |
| Passivation | Stainless steel | Removes free iron, restores the chromium oxide layer |
| Plain / oiled | Fully enclosed assemblies | No coating cost at all |
Two rules save arguments later. Specify finish by performance, not by name — “96 hours to white rust per ASTM B117” is testable, “zinc plated” is not. And on hardened steel parts that are electroplated, insist on a hydrogen embrittlement relief bake performed within the window required by ISO 4042; skipping it produces rivets that pass every inspection and then fracture in the field days later.
9. Inspection and Sorting
Volume fastener inspection runs on three layers. In-process SPC checks key dimensions at set intervals during the run, typically targeting a process capability of Cpk ≥ 1.33 for automotive work. Batch inspection samples per ISO 2859-1 at an agreed AQL, commonly 1.0 or 2.5 for dimensional characteristics. 100% sorting, on an optical or eddy-current sorter, is used where a single defect is unacceptable — mixed parts, missing holes, short heads.
Measurement is done with micrometers and go/no-go gauges for routine dimensions, optical comparators for head profile and radii, and vision systems or CMM for concentricity and reports.
Rivet Materials: What to Specify and Why
Material is chosen for three things at once: how well it flows in the die, how strong the finished rivet is, and whether it will corrode against the parts it joins.
| Material | Common grades | Why it is chosen | Watch out for |
|---|---|---|---|
| Low carbon steel | SAE 1006, 1008, 1010, 1018 (CHQ) | Cheapest, excellent formability, plates well | Needs a coating in any humid environment |
| Alloy / boron steel | 10B21, 10B33 | Heat treatable for load-rated joints | Embrittlement risk after plating |
| Stainless steel | 304 / A2, 316 / A4, 302HQ | Corrosion resistance without coating | 304 work-hardens fast; 302HQ carries added copper specifically to head cleanly |
| Aluminum | 1100, 5052, 5056, 2117-T4 | Light, soft enough to set with hand tools | Galvanic corrosion against steel or stainless |
| Copper | T2 / C11000 | Electrical conductivity, easy setting | Soft, low shear strength |
| Brass | H62, H65 | Decorative, machines and heads well | Dezincification in some environments |
Two grades deserve a note. 302HQ exists because plain 304 hardens so quickly under the punch that heads crack; the added copper buys formability, and it is the default when you want a stainless rivet with a large or complex head. 2117-T4 is the classic aerospace aluminum rivet alloy, soft enough to drive without pre-annealing and stable at room temperature, which is why it dominates aircraft skin work[citation].
If you do not know what to specify, describe the environment and the mating materials instead. Salt spray hours, operating temperature, and what the rivet sits against tell a supplier more than a guessed grade does.
Rivet Tolerances: What Cold Heading Can Actually Hold
This is where most RFQs go wrong. Buyers copy tolerances from a machined-part template, the supplier quotes secondary machining to meet them, and the price comes back three times higher than expected.
Typical as-formed capability for cold-headed rivets:
| Feature | Typical as-formed | With secondary operations |
|---|---|---|
| Shank diameter | ±0.02 – 0.05 mm | ±0.01 mm (turning or centerless grinding) |
| Head diameter | ±0.05 – 0.15 mm | ±0.03 mm (trimming or turning) |
| Head height | ±0.05 – 0.10 mm | ±0.02 mm |
| Overall length | ±0.10 – 0.30 mm | ±0.05 mm (facing) |
| Hole diameter, semi-tubular | ±0.05 – 0.10 mm | ±0.02 mm (drilling / reaming) |
| Shank-to-head concentricity | 0.05 – 0.15 mm TIR | Tighter with turning |
| Head perpendicularity to shank | 1 – 2° | — |
Treat these as the shape of the process, not as a commitment; confirm the numbers against your own drawing with your supplier before releasing tooling.
Why length is the loosest dimension. Overall length depends on cutoff feed length, and the shear blade wears through the run. Diameter, by contrast, is set by a carbide die cavity that barely moves. If your design genuinely needs length held tighter than roughly ±0.1 mm, budget for a facing operation or redesign so the grip range absorbs the variation.
Why head diameter varies more than shank diameter. The shank is constrained on all sides by the die bore. The head is formed in a cavity that must be filled by metal flowing outward, and how completely it fills depends on incoming wire diameter and slug volume. Fill variation shows up as head diameter and head height variation.
Where general tolerances come from. Unless the drawing says otherwise, most suppliers default to ISO 2768-m for unspecified linear dimensions, which gives ±0.1 mm from 0.5 to 6 mm nominal and ±0.2 mm from 6 to 30 mm. Calling out ISO 2768-f instead tightens those to ±0.05 mm and ±0.1 mm, and will raise the price. Put the class on the drawing; do not leave it to be assumed.
Common rivet standards worth citing by name:
- DIN 660 — round head solid rivets
- DIN 661 — countersunk head solid rivets
- DIN 7338 — semi-tubular brake lining rivets
- DIN 7337 / ISO 15973–15984 — blind (pop) rivets, break-mandrel types
- ASME B18.1.1 — small solid rivets, inch series
Referencing a standard is the fastest way to remove ambiguity from a quote. It fixes head geometry, radii, and tolerance in one line.
How Rivet Type Changes the Process
| Rivet type | Formed how | Where the cost sits |
|---|---|---|
| Solid | Headed from wire, sometimes trimmed | Cheapest; a single die set may cover several lengths |
| Semi-tubular | Headed, then pierced in-station | One extra station; still a single-pass part |
| Full tubular | Headed with deep back extrusion | Extra stations; wall thickness limits the design |
| Split / bifurcated | Headed, then the leg is slit | Slitting tool plus handling |
| Blind (pop) | Body and mandrel formed separately, then assembled | Two part flows plus an assembly line |
| Self-piercing (SPR) | Headed and heat treated to a tight hardness band | Heat treat control drives both cost and scrap |
| Shoulder / step | Multi-diameter extrusion | Station count rises with each diameter |
The pattern is consistent: every distinct feature costs a station or an operation. Counting features on your own print is a fair way to predict where a quote will land.
Seven Design Rules That Cut Your Unit Price
- Keep free upset under 2.3× wire diameter per blow. Larger heads are possible, but each one adds a coning station and a die.
- Tolerance what the function needs, nothing more. A single ±0.01 mm callout can move a part from header-only to header-plus-lathe and double the price.
- Start from a standard head profile. DIN 660 or DIN 661 geometry often reuses existing tooling and skips new die development entirely.
- Specify the finish by test result. Salt spray hours are checkable; a coating name is not.
- Consolidate the part family. One diameter in three lengths usually shares a die set. Three diameters never do.
- Say how the rivet will be set. Impact, orbital, radial, and press riveting each want different head hardness and shank length. Suppliers can only optimize for a method they were told about.
- Send tolerances on the features that matter and leave the rest to ISO 2768. Over-specifying every dimension raises the inspection cost on every single piece you buy.
Quality Documentation to Ask For
For anything load-bearing or safety-related, request these up front rather than after the first shipment:
- Mill certificate with heat number and chemical analysis
- Dimensional inspection report against your drawing, with sample size and AQL stated
- Salt spray test report to ASTM B117 or ISO 9227, with hours and failure criteria
- Hardness results, where heat treatment is specified
- RoHS and REACH declarations for EU-bound goods
- PPAP documentation for automotive programs
Asking for these at the RFQ stage also tells you a great deal about a supplier before you place any money.
What to Send for an Accurate Rivet Quote
Most quote delays are caused by missing information, not by pricing. Send these seven items and a competent supplier can usually come back with a firm number and a tooling plan:
- A 2D drawing in PDF, DWG, or STEP. No drawing? A clear photo of the sample next to a caliper, plus the three critical dimensions, is enough to start.
- Material and grade — or, if you are not sure, the environment and the mating materials.
- Surface finish with a required salt spray result.
- Rivet type and setting method — solid, semi-tubular, tubular, blind, and how it will be installed.
- Quantities — first order quantity plus estimated annual usage. Volume changes the tooling decision more than any other input.
- Standards and certificates you need with the shipment.
- Destination and packaging requirements, and a target price if you have one.
Get a Quote from a Cold Heading Factory
Yueqing Yiwan Hardware manufactures custom rivets, pins, screws, nuts, cold forged parts, and CNC-machined components for OEM and industrial customers. The plant runs multi-station cold heading alongside CNC machining, automatic and manual instrument lathes, and punching, so heading and secondary operations happen under one roof instead of moving between subcontractors. Product range covers rivets, stainless steel semi-tubular rivets, nuts, custom bolts, and non-standard parts for automotive, door lock, and electrical hardware applications.
Send your drawing or a sample photo and we will come back with a price, a tolerance assessment, and a tooling plan. If the drawing specifies something the process cannot hold economically, we will say so and propose the change that keeps it cheap.
Frequently Asked Questions
How are rivets made in a factory? By cold heading. Wire is drawn to size, lubricated, sheared into slugs, and struck two to five times in progressive dies to form the head and shank. Tubular and semi-tubular types are pierced in the same machine. Parts are then deburred, plated if required, inspected, and packed.
Are rivets forged or machined? Forged, in the cold state. Machining a rivet is possible and is sometimes used for prototypes or very low volumes, but it cuts through the grain structure and wastes material, so production rivets are formed.
What machine makes rivets? A multi-station cold heading machine, also called a header or cold former, described by its die and blow count. Secondary operations use lathes, drilling machines, thread rollers, and punches.
What are rivets usually made from? Low carbon steel, stainless steel (304, 316, and the cold-heading grade 302HQ), aluminum, copper, and brass. Steel is the default for cost, stainless for corrosion resistance, aluminum where weight matters, and copper where the joint must conduct.
How are semi-tubular rivets made? The same as solid rivets, with one extra station where a punch forms the hole in the shank while the part is still gripped in the die. This keeps the hole concentric. Hole depth stays within 112% of the shank diameter, leaving solid material to carry shear.
How are pop rivets made? The body and the mandrel are cold headed on separate machines, then assembled so the mandrel head seats inside the rivet body. Closed-end and open-end versions differ in how deeply the body is extruded.
What tolerance can a cold-headed rivet hold? Typically ±0.02 to 0.05 mm on shank diameter, ±0.05 to 0.15 mm on head diameter, and ±0.10 to 0.30 mm on overall length. Tighter values are achievable with secondary machining at additional cost.
Do custom rivets need new tooling? Usually yes, unless the geometry matches an existing die set. Standard head profiles such as DIN 660 and DIN 661 are the most likely to reuse tooling. Confirm tooling cost and lead time with your supplier before releasing the order.
What is the minimum order quantity for custom rivets? It depends on whether tooling already exists and on the material. Because a header runs hundreds of pieces per minute, per-piece cost falls sharply with volume; ask your supplier for a price break table rather than a single-quantity quote.
Publishing Pack (not part of the article)
Recommended SEO title tag: How Are Rivets Made? Custom Rivet Process, Materials & Tolerances The exact phrase “how are rivets made” belongs at the front of the title tag for exact-match relevance. Keep your H1 as written on the page; the title tag can differ from the H1.
Meta description (154 chars): How are rivets made? A cold heading engineer's guide to the rivet manufacturing process, materials, tolerance bands, and what to send for a fast quote.
URL slug: /how-are-rivets-made/ — short, exact match, no dates.
Primary keyword: how are rivets made Secondary keywords to keep in headings and body: rivet manufacturing process, cold heading rivets, custom rivets manufacturer, how are semi-tubular rivets made, rivet materials, rivet tolerances, cold forming fasteners, how are pop rivets made
Schema: Add Article markup with author and organization. FAQPage markup is still worth adding for machine understanding, though Google restricted FAQ rich results to authoritative government and health sites in 2023, so do not expect star-style SERP features from it.
Image slots to add (real photos from your own floor will outrank stock images and are your strongest E-E-A-T signal):
- Multi-station cold heading machine mid-run — alt:
multi-station cold heading machine producing rivets - Die and punch set on the bench — alt:
cold heading dies and punches for rivet production - Progression sample: wire, slug, coned blank, finished rivet — alt:
rivet cold forming progression from wire to finished part - Semi-tubular rivet cross-section — alt:
semi-tubular rivet cross section showing hole depth - Inspection station with optical comparator — alt:
rivet dimensional inspection with optical comparator
Internal links used: homepage, rivets category, tubular rivet, nuts category, custom bolt, products. Add a link from your rivets category page back to this article to pass relevance the other direction.
Items to verify or replace before publishing:
- Confirm your actual cold heading machine count, tooling lead time, and MOQ, then add them to the FAQ. Specific numbers convert far better than “it depends.”
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