How to Choose a Bolt Former: Stations, Size, Stroke
Choose a bolt former by working backwards from the part: its head shape, its diameter and its length decide the number of die stations and the stroke you need. YESWIN's range covers M3 to M30, with 3, 4 and 5 station models and long stroke versions for lengths up to 400 mm.
The right machine is rarely the one with the most stations. Extra stations cost money and floor space, and a simple hex head bolt gains nothing from them. This guide walks through the five checks that settle the choice, then lists what to send so a quote can be accurate.
Last updated: 2026-11-11
Table of contents
What should you check first when choosing a bolt former?
Start with the finished part, not the machine catalogue. Five facts about the part narrow the field faster than any spec sheet.
- Head shape. A plain hex head is a single upset. A flange, a shoulder or a deep socket needs more material movement, and that is where extra stations earn their place.
- Diameter. YESWIN bolt formers cover M3 to M30. Parts formers for special shapes cover M6 to M30.
- Length. This decides standard or long stroke. Long stroke models reach up to 400 mm.
- Shank features. Stepped shafts, multiple diameters and semi-threaded bodies push the choice towards four or five stations.
- Volume and changeover. A line that runs one part for months values different features than a shop that changes dies every week.
Demand is not the constraint. Taiwan's fastener exports reached 327,100 tons in the first quarter of 2025, up 3.37 percent year on year (Fastener World, 2025). The pressure is on cost per part and on how quickly a plant can change over, which is why the number of stations should match the part rather than exceed it.
How many stations does your part need?
Use the fewest stations that form the part cleanly. Each added station gives the metal one more controlled step, but only parts with complex geometry need it.
The reason is load. A laboratory study of a five-stage cold forming sequence on AISI 1010 regulating nuts, run on a 20-tonne test press, measured peak forces of 117.5, 51.7, 62.0, 191.3 and 27.0 kN across the stages, 449.4 kN in total. The heaviest stage carried about 43 percent of the combined load (Yang and Liu, MDPI Applied Sciences, 2023). It is a nut study, not a bolt study, but it shows the principle: spreading deformation over several blows keeps each blow manageable.
| Stations | Part complexity | Typical parts | Choose it when |
|---|---|---|---|
| 3-station | Simple head shapes | Hex head bolts, cap screws, flange bolts | You run high volumes of a straightforward part |
| 4-station | Moderately complex | Hex, shoulder and flange bolts, weld bolts, stepped shaft fasteners | The head or shank needs one more forming step |
| 5-station | Complex geometry | Automotive bolts, special flange screws, banjo and cam bolts, wheel and hub bolts, T bolts, hammer head bolts, guide pins, axles, quick connectors | The part has multiple diameters or deep features |
Source: YESWIN product pages. Confirm your exact part against the model before ordering.
Standard or long stroke: which fits your bolt length?
If your bolts are long, choose a long stroke model first and the station count second, because length limits the machine before shape does.
Standard and long stroke formers both cover M3 to M30. The long stroke line extends the maximum bolt length up to 400 mm, and it comes in 3, 4 and 5 station versions. Three stations suit simple, standard shapes. Four stations suit longer or semi-threaded bolts. Five stations suit complex geometry, deep heads and stepped features.
Typical long parts include construction screws, anchor bolts, elevator bolts, concrete screws, timber screws, roofing screws and connecting rods. A longer shank also gives the wire less support during the blow, so tooling and feeding matter more as length grows. If your range sits near the upper limit, ask for the exact length your target model can take before you commit. See the long stroke bolt former range.
Which features are worth paying for?
Pay for the features that cut changeover time and scrap on your parts, and skip the ones that solve problems you do not have.
Standard equipment on YESWIN bolt formers includes an air clutch, an ABB inverter, a frequency conversion motor, the Q.T.C. close-cutter mechanism, the P.K.O. mechanism, a spring or pneumatic transfer mechanism, interval feeding and a safety detection device. Options are where you decide what to add:
- Servo adjustments for feeding, stopper and K.O. help when you change parts often and want repeatable settings.
- CBK quick changing for punch and die blocks is an option, not a standard item, and it matters most on short runs.
- HMI operation panel and a digital gauge for punch wedge adjustment support consistent setup between operators.
- Sound-proof cover and a short parts supporter address the plant environment and short-part handling.
Ask which items are standard on the exact model you are quoting, because the list can differ between models.
What should you send with a quote request?
Send the drawing and the numbers around it. A quote built on a drawing is faster and far less likely to change later.
- 1. Part drawingHead shape, shank profile, thread and total length.
- 2. Size and standardNominal diameter and the product standard, for example ISO 898-1 property class.
- 3. MaterialWire grade and diameter you plan to use.
- 4. VolumeMonthly quantity and how often you change parts.
- 5. OptionsQuick change, servo adjustment or noise requirements.
Remember that the machine forms the shape only. The mechanical property class of a bolt under ISO 898-1, which covers carbon and alloy steel bolts, screws and studs in coarse thread sizes M1.6 to M39, depends on the material and the heat treatment that follow, not on the former itself.
Frequently asked questions
Is a 5-station bolt former always better than a 3-station one?
No. A 5-station machine handles more complex geometry, but a simple hex head or cap screw gains nothing from the extra stations. Match the station count to the part shape and you avoid paying for capacity you never use.
What size range do YESWIN bolt formers cover?
The standard and long stroke bolt formers cover M3 to M30. The bolt parts formers and nut parts formers cover M6 to M30. Long stroke models reach bolt lengths up to 400 mm.
When do I need a long stroke bolt former?
Choose a long stroke model when your bolt length goes beyond what a standard model handles. Typical examples are anchor bolts, elevator bolts and concrete screws. Send your longest part drawing so the sales team can confirm the length against the model.
Can one bolt former make studs and T bolts?
Double-end studs, welding studs and T bolts appear in the capability lists of YESWIN models, and T bolts are listed on the 5-station page. Because stud and T bolt lengths vary widely, confirm your part against a specific model before ordering.
Does the bolt former decide the strength class of the bolt?
No. The former shapes the part. The property class depends on the wire material and on heat treatment, and it is specified in standards such as ISO 898-1. Plan material and heat treatment alongside the machine choice.
Not sure which model fits your part?
Send us the drawing and the target volume. We will tell you which station count and stroke to look at.