Sprockets

Sprockets are the toothed wheels that engage with roller chain to transmit power between shafts. Get the chain, sprocket, and bore configuration right and the drive runs for years with routine lubrication. Get any of those three wrong — wrong pitch, wrong tooth profile, wrong bore type — and you'll be replacing chain and sprockets together inside months. This collection brings together BS (British Standard) and ASA/ANSI sprockets across pilot bore, taper lock, weld-fit, and plate wheel configurations for simplex, duplex, and triplex roller chain drives.

Sprocket Sizing & Chain Compatibility — Quick Reference

Critical rule: BS and ASA pitches are NOT interchangeable, even where they share the same nominal pitch. Tooth profiles, roller diameters, and inner widths differ between the two standards. Always match the sprocket to your existing chain standard — confirm the chain markings before ordering. If in doubt, send us a photo of the chain side plate and we'll identify the standard for you.

ANSI vs ISO Sprocket Sizing — Two Standards, Two Numbering Systems

ASA/ANSI B29.1 (American Standard)

The American chain numbering system encodes pitch in eighths of an inch. Take the chain number, drop the last digit, and you have pitch in eighths: a #40 chain is 4/8 = 1/2" pitch. A #80 is 8/8 = 1" pitch. A #160 is 16/8 = 2" pitch. The trailing zero indicates standard roller chain; trailing "1" indicates lightweight (e.g. #41); trailing "5" indicates bushed chain without rollers.

ASA/ANSI sprockets are required for equipment imported from North America or specified to ANSI standards. Common North American agricultural, packaging, and food machinery uses #40, #50, #60, and #80 chain.

ISO 606 / BS / DIN 8187 (European-Asian Standard)

ISO 606 chain (often called BS in Australia, DIN 8187 in Germany) uses a different numbering convention: the leading number indicates pitch in 16ths of an inch, and "B" denotes British/European series. So 08B = 8/16 = 1/2" pitch, 12B = 12/16 = 3/4" pitch, 16B = 16/16 = 1" pitch. The "A" series (08A, 10A) exists but is functionally identical to ANSI and rarely stocked in Australia.

BS sprockets dominate Australian, UK, and European-built machinery. Most Australian agricultural, conveyor, and industrial OEMs spec BS chain by default.

Pitch Diameter Calculation

For both standards, sprocket pitch diameter (PD) is calculated as: PD = pitch ÷ sin(180° ÷ N), where N is the number of teeth. The PD is the diameter of the circle that passes through the centre of each chain pin when the chain is wrapped on the sprocket. This matters when calculating centre distance between two sprockets on a chain drive.

Sprocket Type Variations

By Number of Chain Strands

• Simplex (single strand): One row of teeth, paired with single-strand roller chain. The most common configuration for general industrial drives.
• Duplex (double strand): Two rows of teeth machined on one sprocket body, paired with duplex chain. Delivers roughly 1.7× the torque capacity of an equivalent simplex setup for the same pitch — useful when you need more capacity without going to a larger chain size.
• Triplex (triple strand): Three rows of teeth, paired with triplex chain. Roughly 2.5× simplex torque capacity. Specified for heavy industrial drives, mining, and large conveyors where compact high-torque transmission is needed.

By Hub Configuration (Type A/B/C/D)

• Type A — Plate sprocket (no hub): Simple flat disc with central bore. Bolts onto an existing hub or flange, or welds directly to the shaft. Used where space is tight or where the host equipment already has the mounting hardware.
• Type B — Single-side hub: Hub projects from one face only. Standard configuration for most general drives — the hub side faces away from the chain, the plate side carries the teeth.
• Type C — Double-side hub: Hub projects from both faces, increasing axial support on the shaft. Specified for heavier drives or where the sprocket needs more grip on the shaft for stability.
• Type D — Split sprocket: Two-piece construction that bolts together around the shaft. Allows installation and removal without disturbing the shaft or adjacent bearings. Premium spec for hard-to-access drives, common on conveyor head shafts and large agricultural drives.

By Bore Style

• Pilot bore: Sprocket arrives with a small pilot bore (e.g. 6 mm). Customer or workshop machines the bore to the exact shaft diameter and cuts the keyway. Maximum flexibility for non-standard shafts.
• Stocked bore (finished bore): Bore is pre-machined and keywayed to a common shaft size (1", 25 mm, etc.). Drop-in fit for the listed shaft size only.
• Taper lock bore: Bore is machined to accept a standard taper lock bush. The bush takes the keyway and grips the shaft via tapered interference. Quick install, quick removal, no specialist tooling needed. See our taper lock bushes range for the matching components.
• Weld-fit: Sprocket has no finished bore — it's a tooth ring designed to be welded onto a custom hub or directly to the shaft. Used in conveyor head/tail shafts, agricultural machinery, and bespoke industrial drives.

Sprocket Materials

• Plain carbon steel: The default material for general industrial sprockets. Good wear resistance at moderate cost. Suits clean, lubricated workshop and conveyor drives. [VERIFY:] Most BS/ASA stock sprockets are supplied in C1045 or equivalent medium-carbon steel.
• Hardened tooth (induction or through-hardened): Tooth surface hardened to roughly 45-55 HRC while the hub remains tough. Delivers 3-5× the tooth life of plain carbon steel in abrasive or high-duty applications. Specified for mining, quarry, foundry, and continuous-duty drives.
• Stainless steel (304 / 316): Corrosion-resistant for food processing, beverage, marine, and chemical environments. 316 is the food and marine standard. Lower wear resistance than hardened carbon steel — replace at shorter intervals.
• Cast iron: Lower cost, used for large-diameter, low-speed sprockets where weight isn't critical. Limited shock load capacity.
• Polymer / nylon: Self-lubricating, no chain oil required. Suits food, pharmaceutical, and cleanroom applications where contamination from chain lube is unacceptable. Capacity limited — not for heavy duty.

Selection Criteria

Five questions to answer before ordering a sprocket:

1. What chain are you running? Standard (BS or ASA), chain designation (08B, #40, etc.), and number of strands (simplex/duplex/triplex). The sprocket must match all three.
2. How many teeth do you need? Tooth count drives speed ratio and chain life. Minimum 17 teeth is recommended for smooth running; absolute minimum is around 12-13 teeth. Below that, chain articulation angle becomes excessive and chain life drops sharply. Maximum is set by available space.
3. What's your shaft size and bore preference? Pilot bore (you machine), stocked bore (drop-in fit), taper lock (clean install/remove), or weld-fit (custom hub).
4. What's the operating environment? Clean and lubricated = carbon steel. Abrasive or heavy duty = hardened tooth. Wet, corrosive, or food contact = stainless. Cleanroom = polymer.
5. What's the service factor? Light continuous (1.0), moderate shock load (1.2-1.4), heavy shock (1.6-2.0). Multiply the calculated drive torque by the service factor when sizing chain and sprockets.

Installation & Maintenance

Taper Lock Installation

Taper lock sprockets are the maintenance-friendly choice. Install the bush into the sprocket bore (flange side out), align the bolt holes (offset, not opposite), tap the bush into position, then tighten the cap screws progressively in a star pattern to the bush manufacturer's torque spec. Always use a torque wrench — over-tightening can crack the bush flange, under-tightening allows the sprocket to slip on the shaft under load. See the taper lock bush guide for the full procedure and torque values.

Drive Alignment

Both sprockets must be parallel and in the same plane. Use a straightedge laid across both sprocket faces to check parallelism, and a feeler gauge or laser alignment tool to confirm axial offset is within 0.5 mm per metre of centre distance. Misalignment causes uneven tooth wear, chain side-plate fatigue, and premature failure of both chain and sprockets.

Chain Tension

Roller chain should run with a small amount of slack — typically 2-3% of the centre distance on the slack side. Too tight and you'll overload bearings and accelerate chain wear; too loose and the chain will whip, jump teeth, or throw under shock loads. A take-up adjustment or an idler sprocket (also stocked in this range) sets and maintains tension over the drive's service life.

Lubrication

Roller chain needs lubricant penetration between the pin and bushing. A purpose-formulated chain lube (drip, spray, or oil bath depending on speed and duty) is what extends chain — and sprocket — life. Generic grease on the chain plates doesn't reach the pin-bushing interface where wear actually happens. See our lubrication range for chain-specific lubricants.

Common Applications

Conveyors

Food processing, packaging, mining haul, parcel sorting, and general material handling. Conveyor head and tail shafts typically use Type B or Type C sprockets in BS series, with hardened teeth for continuous-duty installations. Stainless 304 or 316 for food contact.

Mining & Quarry

Heavy-duty drives on screens, crushers, and apron feeders. Larger BS sizes (16B, 20B, 24B) or ASA #80-#160 in hardened-tooth specification. Weld-fit or split-hub configurations are common to allow shaft-mounted maintenance without dismantling adjacent gearboxes.

Food & Beverage Processing

Bottling lines, biscuit ovens, dairy processing, meat works. Stainless 316 sprockets paired with stainless or polymer chain, or food-grade polymer sprockets for wash-down hygiene. NSF H1 chain lubricants where lube is permitted.

Agricultural Machinery

Harvesters, balers, augers, conveyor feeds, planters. Mix of BS and ASA depending on OEM origin — European tractors and implements tend BS, North American iron tends ASA. Hardened-tooth weld-fit is common on header drives and auger shafts.

Machine Tool & Workshop

Lathe feed drives, mill table drives, small conveyors. Lower-duty BS sizes (06B, 08B) in pilot or stocked bore. Carbon steel typical.

Motorcycle & Light Mobility

Rear-wheel drives, small industrial vehicles. Lighter ASA series (#40, #41, #50) — usually OEM-specific so confirm part numbers before ordering generic replacements.

Brand Range

• Renold: UK-engineered premium chain and sprockets. The benchmark for heavy-duty industrial drives and the brand specified by most Australian engineering consultants for new-build mining and processing plant.
• KCM: Japanese roller chain and sprocket manufacturer. Strong reputation for quality and dimensional precision at a mid-tier price point. Common across Australian general industry.
• SY: Asian-manufactured value range — competitive pricing for lighter-duty and replacement applications where premium spec isn't justified.
• Finer Power Transmissions: Broad Australian-distributed power transmission range, including sprockets, taper bushes, and pulleys.

Sprockets supplied via this collection are matched to the chain ranges we stock — confirm chain brand and standard when ordering replacement sprockets to maintain a homogeneous drive.

Companion Components

• Roller chain: The mating component. Always order chain and sprockets together when refurbishing a drive.
• Chain & sprockets bundles: Paired chain and sprocket combinations for common drive configurations.
• Taper lock bushes: Match your taper-lock-bore sprockets to the correct bush size (1008, 1108, 1610, etc.).
• Bearings: Pillow blocks, flange units, and inserts for the shafts your sprockets run on.
• Couplings: Chain couplings, jaw couplings, and grid couplings for connecting motor shafts to driven shafts.
• Key steel and key stocks: Square and rectangular key stock for keyway cutting on pilot-bore sprockets.
• Pulleys: If you're considering whether chain or belt is the right drive for your application, our pulleys range covers the alternative.
• Lubrication: Chain lubricants, including food-grade NSF H1 options.

AIMS' Note on Sprocket Selection

If you're replacing a worn sprocket, the safest path is to send us the chain markings, the existing sprocket's tooth count, and the shaft diameter (and bore style if known). With that, we can match the replacement to your existing drive without guesswork.

If you're specifying a new chain drive from scratch, give us a call. The chain-drive selection involves five interlocking decisions — chain standard, chain designation, sprocket teeth count, sprocket material, and bore style — and Sam's team can walk through the application with you in about ten minutes. We'd rather have that conversation up front than fix a wrong-spec drive later.

Same-day dispatch on in-stock items from our Milperra warehouse (Sydney NSW). Larger sizes and hardened-tooth specifications may be indent — we'll confirm freight ETA when you place the order.

Companion Resources

• Belt vs Chain Drives: Selection by Application & Trade-Offs — the strategic decision before you specify sprockets at all.
• Pulley Speed Ratio Calculator & Formula — same maths applies to sprocket drives (driver teeth × driver RPM = driven teeth × driven RPM).
• Bearings & Power Transmission Guide — the broader power transmission picture.
• Taper Lock Bush Guide — sizes, installation procedure, torque values, and removal technique.

Australian business since 1988. Locally stocked, locally supported. Call (02) 9773 0122 or contact our team with your chain pitch, tooth count, and shaft details — we'll get you the right sprocket for your drive.