Replacing a chain? Identify it first
Most conveyor chain enquiries are replacements, and the fastest route is to identify what is fitted rather than re-select from scratch, because the conveyor was designed around it. Look for the size stamped on the side plates, then measure the pitch and roller. Double-pitch chain (C2040, C2062H and so on), BS/ISO conveyor chain and the FV series each have their own numbering; our chain identification guide covers the measurements, and a photo next to a rule settles the rest.
Two cautions before you order like-for-like. First, if the old chain wore out early, copying it repeats the problem. Check the fault finder to see whether the failure points to lubrication, alignment, overload or environment, because the answer may be the same chain in stainless steel or self-lube, or a stronger construction. Second, worn chain measures long: take the pitch over several links and read our wear guide so you don't misidentify a 1" chain as something odd.
Five questions, in order
1. What carries the load, and how?
This is the question that separates the ranges. Product can ride on the chain's own rollers along a track (large-roller double-pitch chain, C20x2); sit on slats or fixtures bolted to attachment plates (A/K attachments on double-pitch or BS/ISO chain); be dragged by scrapers or flights (welded steel and BS conveyor chain with integral scrapers); hang from trolleys on an overhead circuit (drop-forged rivetless chain); or be lifted in buckets (BS/ISO and cast chain). Answer this and you have narrowed the field to one or two ranges. The table below maps duty to range.
2. What load, and how is it applied?
Every range publishes a minimum breaking load per size. For the FV series the number is the load: FV63 is a 63 kN chain, FV250 a 250 kN chain, running FV40 to FV630. Double-pitch chain lists ISO 1275 minimums per size on the range page. Those figures are the starting point, not the answer: the working load must leave room for starting torque, shock, uneven loading and the wear the chain will accumulate over its life. Steady, smooth conveying and a shock-loaded elevator can share a breaking-load figure and need very different chain.
Let us size it with you. Send the mass on the conveyor, its length and incline, speed, drive arrangement and duty cycle, and we'll come back with a size and say why. It is quicker than guessing a service factor, and it costs nothing.
3. What environment?
- Washdown, food, moisture: stainless steel versions of the double-pitch and attachment ranges are held in UK stock; where re-lubrication is impossible, NSF H1 self-lube (NSL) chain runs without it. Stainless steel has lower strength than carbon steel of the same size, so check the load, not just the material.
- Corrosive but not washdown: coated carbon steel keeps the strength. Our coating comparison gives real ASTM B117 salt-spray hours (CRF/GEOMET ≥600 h, GN ≥500 h, MZP >60 h, NP ~20 h) so you can match the finish to the exposure.
- Heat: NSL FG runs to 145 °C and FGH to 220 °C without lubrication. See the self-lube page.
- Abrasive, slow and heavy: welded steel or cast chain, which tolerate grit that would destroy precision roller chain joints.
- Marking or noise on the product: non-marking and plastic-roller chain. The strength trade-off is stated plainly on that page.
4. What path does the chain follow?
Straight runs suit any of the above. Curves in plan need side-bow chain (curve radii from 254 mm); a path that turns in two planes needs Double Flex; and a line where product must queue without back-pressure needs accumulation chain. Get the path wrong and the chain will run, briefly.
5. What attachments, at what spacing?
Attachment type (A1, K1, A2, K2, SA1, SK1, extended pins), which side, every pitch or every nth, and whether you need hollow pins for rods and spindles. This is where most conveyor chain becomes a made-up assembly rather than a stock item. We build attachment chain to your spacing in Malvern, and the spacing you give us goes on file for the repeat order.
Duty → range
| If the duty is… | Start with | Note |
|---|---|---|
| Product carried on the chain rollers along a track | Double-pitch large-roller (C20x2) | Standard-roller C20x0 where the chain runs on sprockets only |
| Slats, flights or fixtures bolted to the chain | Double-pitch with A/K attachments · BS/ISO conveyor with K attachments | Attachment spacing built up in-house; hollow pin for rods and spindles |
| Machine drawing quotes BS 4116, ISO 1977, DIN 8167/8168 or an FV number | BS / ISO / FV conveyor chain | FV number = minimum breaking load in kN (FV40–FV630) |
| Scraper, drag or rough bulk handling: abrasive, heavy, slow | Welded steel mill chain (WR/WH) | Where precision roller chain would not survive |
| Water treatment, bucket elevators, abrasive process conveyors | Cast & combination chain | Supplied to order; identified from stamping or sample |
| Overhead conveyor with trolleys | Drop-forged rivetless (X348–X678) | Links assembled and dropped out by hand, no splitting tools |
| Product needs to accumulate without back-pressure | Accumulation / Double-Plus chain | Free-flow buffering ahead of a machine |
| Conveyor curves in plan | Side-bow chain | Curve radii from 254 mm |
| Timber, boards or product that must grip the plates | Sharp top chain | Tooth-profiled plates |
Common mistakes
- Choosing on pitch alone. Same pitch, different roller, plate or attachment, and a different breaking load. Match all of it.
- Standard roller where the chain rides a track. Supported conveying wants the large-roller C20x2 construction; on standard rollers the plates drag on the track.
- Stainless steel without checking the load. Corrosion resistance costs strength; size up or move to a coated carbon-steel chain if the numbers don't work.
- New chain on worn sprockets. A worn sprocket wears a new chain to its own pitch in a fraction of the normal life. See measuring wear.
- Forgetting lubrication. Even the right chain fails early run dry; if it can't be lubricated in service, specify a chain that doesn't need it.
Common questions
What is the difference between roller chain and conveyor chain?
Roller chain transmits power between sprockets on a drive; conveyor chain carries product: on its rollers, on attachments bolted to the plates, or by dragging material with scrapers. Conveyor chain usually has a longer pitch for the same strength (double-pitch chain shares the roller and plate sizes of ANSI drive chain at twice the pitch) and is specified by what it carries and how, not just by pitch.
How do I choose conveyor chain by breaking load?
Start from the published minimum breaking load for the range (for FV-series chain the series number is the minimum breaking load in kilonewtons; double-pitch chain lists ISO 1275 minimums per size), then allow for shock, starting loads and wear over the chain's life. If you send us the load, speed, centres and duty cycle we will size it with you rather than leave you to guess a factor.
Which conveyor chain for a food or washdown line?
Stainless steel double-pitch or attachment chain for corrosion resistance, or NSF H1 self-lubricating (NSL) chain where you cannot re-lubricate. Note that stainless steel chain has lower strength than carbon steel of the same size, so check the load, not just the material.
Can I choose conveyor chain by pitch alone?
No. Pitch tells you the sprocket it will run on and nothing else. Chains of the same pitch differ in roller size, plate thickness, attachment pattern, material and breaking load. Match the roller type, the attachment and the load as well.
Not sure which range?Send the drawing, the duty or the old chain and we'll specify it and quote.
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