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Pitch is the single most important dimension in roller chain nomenclature. It describes the centre-to-centre distance between adjacent pins, and every other dimension of a chain — roller diameter, inner plate width, pin diameter, breaking load — is determined in proportion to it. In the British Standard (BS ISO 606) system, pitch is expressed in sixteenths of an inch, which is then multiplied by a prefix number to give the chain’s designation. So a 10B chain has a pitch of 10 sixteenths of an inch, which is 5/8 inch or 15.875 mm. A 16B chain has a pitch of 16 sixteenths — exactly one inch (25.4 mm). This mathematical relationship makes British chain codes straightforward once the sixteenth-of-an-inch rule is memorised.

In the ANSI/ASME B29.1 system, used predominantly in North America but encountered frequently in global trade, the numbering logic is slightly different. The first one or two digits of the chain number, when divided by 8, give the pitch in inches. An ANSI 40 chain therefore has a pitch of 40/8 = 0.5 inch (12.7 mm). An ANSI 80 chain has a pitch of 80/8 = 1 inch (25.4 mm). The absence of a suffix letter in the base code is itself informative: it indicates a standard ANSI chain, whereas a suffix letter signals something else (heavy series, offset link plate, etc.). Understanding both numbering systems is essential for any UK buyer dealing with machinery imported from North America, Japan, or mainland Europe, where ANSI specifications are routinely mixed with ISO-based designations.

• Pitch in sixteenths of an inch (suffix B)
• Inner link width in millimetres for B-series
• Dominant in UK, EU, and Commonwealth markets
• Common sizes: 06B, 08B, 10B, 12B, 16B, 20B, 24B
• Preferred by OEMs in Birmingham, Manchester, Bristol
• Used in most British-manufactured agricultural machinery

• Pitch = number ÷ 8 (in inches)
• Narrower inner width than BS at same pitch
• Widely used in imported US/Japanese machinery
• Common sizes: #25, #35, #40, #50, #60, #80, #100
• H suffix = heavy series with thicker plates
• Encountered in automotive and packaging plant imports

A roller chain transmits mechanical power through a sequence of interlocked links where each roller engages a sprocket tooth, rotates freely on its bushing, and disengages cleanly as the chain wraps around the sprocket arc. The rolling contact between roller and tooth minimises sliding friction, which is the primary reason roller chains achieve transmission efficiencies routinely above 97% — a figure that even well-maintained flat belts cannot match at equivalent loads. The chain’s inner link plates are pressed tightly onto the bushings, whilst the outer link plates hold the pins. The pin rotates inside the bushing as the chain articulates around the sprocket, and the bushing itself is what the roller rides upon.

The material selection for each component is a carefully engineered balance. Link plates are typically cut from medium-carbon or alloy steel strip, heat-treated to a core hardness that provides toughness against shock loading while the surface remains machinable. Pins are produced from case-hardened alloy steel and ground to close tolerances — typical pin roundness tolerances in precision-grade chains are held within 0.005 mm. Bushings and rollers are made from low-carbon steel that is carburised and case-hardened, giving a hard outer shell capable of withstanding the rolling/sliding contact with the sprocket tooth and pin surface respectively. The differential hardness between pin and bushing is deliberately engineered to ensure the bushing wears preferentially, since it is the less expensive component to replace in a rebuild scenario. For stainless steel chains — increasingly popular in UK food factories, chemical plants in Teesside, and pharmaceutical facilities in the Midlands — AISI 304 or AISI 316 is used throughout, accepting a lower tensile strength in exchange for substantially improved corrosion resistance.

Precision timing chains and transmission drive chains on assembly lines demand exact pitch compliance and low elongation rates. The West Midlands automotive corridor — covering plants from Coventry to Solihull — typically specifies 10B-1 and 12B-2 roller chains for conveyor systems, with ANSI 50 and ANSI 60 used on American-sourced pressing equipment. Precise size designation ensures interoperability during planned maintenance windows where downtime is measured in vehicle units per hour, not minutes.

Combine harvesters, balers, and grain auger systems in Lincolnshire and Cambridgeshire rely extensively on large-pitch BS chains — 16B, 20B, and 24B are standard across British agricultural OEM output. Duplex chains (-2) are common on main drive shafts where high torque is transmitted, while straw-handling conveyors may use specialist attachment chains with bent or extended link plates. The naming code must account for pitch, strand count, and attachment specification simultaneously when ordering replacement parts during the short harvest window.

Abattoirs, dairy processing facilities, and ready-meal production lines across Yorkshire require stainless steel roller chains (SS suffix, AISI 304 or 316) to meet HACCP compliance and withstand repeated washdown cycles. The size designation must include both pitch and the SS specification; substituting a standard carbon steel 08B-1 for an 08B-1-SS due to a misreading of the code carries serious food safety implications. Many modern UK food processing sites have migrated to chains with self-lubricating sintered bushings (ZB suffix) to eliminate external lubrication in food-contact zones entirely.

Rolling mills, coil handling lines, and slag processing equipment in South Yorkshire demand chains at the extreme end of the size range — 24B-3 and larger, or ANSI 160H heavy series — where breaking loads exceed 400 kN and shock resistance is paramount. At these sizes, chain mass itself becomes a factor in dynamic load calculation, making precise weight-per-metre data from the size designation table directly relevant to drive engineering. Sheffield-based maintenance teams typically hold critical spares in the 16B to 24B range due to long lead times on very large pitch chains from European suppliers.

Automated sortation conveyors, pallet movers, and overhead trolley systems at UK distribution hubs along the M1 and M6 corridors use predominantly small-pitch BS chains — 06B-1 and 08B-1 are the workhorse specifications. The volume of chain consumed in a large distribution centre can run to hundreds of metres per maintenance cycle, making accurate size designation critical for bulk ordering accuracy. Rubber-top attachment chains (G suffix) are used in manual-picking zones where product surfaces must be protected during conveying.

A 20B-pitch chain with factory-fitted rubber top plates — ideal for conveyor lines handling fragile or surface-sensitive goods in packaging and light manufacturing. The rubber bonding meets food-grade contact specifications and withstands routine washdown.

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Ever Power’s manufacturing operation runs across dedicated roller chain production lines equipped with CNC pin and bushing grinding centres, automated plate blanking presses, and continuous chain assembly and tensioning equipment. The result is dimensional consistency that meets or exceeds BS ISO 606 tolerance classes across the entire product range, from the smallest 04B pitch chains up to 48B heavy industrial chains. Every batch undergoes load testing — each completed roller chain is proof-loaded to 50% of its published minimum breaking load before despatch, generating a traceable test record that accompanies the shipment documentation.

For UK buyers, Ever Power’s supply chain infrastructure means genuinely fast turnaround on standard sizes — warehouse stock in the most-used BS and ANSI designations supports ex-stock fulfilment with DDP (Delivered Duty Paid) shipping options direct to UK mainland addresses, eliminating import customs uncertainty from the procurement equation. For engineered or custom specifications, a dedicated project engineering team handles drawing review, prototype production, and first-article inspection before full-production orders are released. Lead times for custom roller chain configurations — including bespoke attachment patterns, extended pitch series, or corrosion-protected finishes outside the standard stainless grade — are agreed contractually and monitored against milestone reporting.

The 24B-G1 occupies the intersection between the large-pitch drive chain world and the conveying chain market. With a 38.1 mm pitch providing substantial breaking load capacity and the factory-bonded rubber top plate offering non-slip, product-safe carrying surfaces, this variant is particularly well-suited to inclined conveyor applications in bottling plants, tyre manufacturing, and general automotive parts handling — industries with a strong presence in the Midlands and North of England. The G1 designation specifies a single rubber pad per link, centred above the outer link plate, providing smooth contact without aggressive grip that could mark finished surfaces.

View 24B-G1 Specifications →

“The shot-peened 10B-2 chain Ever Power supplied has genuinely exceeded our expectations in terms of elongation resistance. We are 8,000 hours in and still well inside the replacement threshold — a dramatic improvement over what we had before. The batch test certificates gave our quality team exactly the traceability documentation they needed.”

“What struck me most was Ever Power’s engineering team actually read our load data and recommended the uprated plate specification rather than simply supplying a direct like-for-like. That kind of proactive technical engagement is rare in chain supply — most distributors just process an order number. The 18-day DDP delivery to Wakefield was excellent given the volumes involved.”

“We have since placed three follow-on orders for smaller BS sizes — 06B-1 and 08B-1 for ancillary equipment — and the consistency between batches has been exactly what a maintenance programme needs. No adjustment required on the sprocket mesh when fitting new sections, which tells you the manufacturing tolerances are genuinely being held. Ever Power is now our primary chain supplier.”