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When a worn or undersized sprocket is causing chain skip, premature wear, or misalignment in your drive system, finding a dimensionally accurate replacement matters. This 08B simplex roller chain sprocket is designed for engineers, maintenance technicians, and serious DIYers who need a reliable pilot bore sprocket they can machine to their exact shaft size — without compromise.
Each sprocket is machined from 45# carbon steel, offering a solid balance of hardness and machinability. The pilot bore design ships with a standard through-bore that you finish-bore and key to your shaft specification. Tooth counts range from 12T to 30T, covering a wide spread of drive ratios. The 08B chain standard specifies a 1/2" (12.7 mm) pitch, with roller diameter typically 8.51 mm (0.335") and inner plate width typically 7.75 mm (0.305").
Typical applications include conveyor drive systems requiring an 08B simplex sprocket replacement, small industrial gearbox output shafts needing a pilot bore sprocket for custom shaft fitting, and hobbyist or maker projects using standard 08B roller chain for power transmission builds.
Ships with a standard pilot bore so you can finish-bore, ream, and key the sprocket to your exact shaft diameter — ideal for precision drive builds.
Machined from 45# medium-carbon steel, delivering the hardness needed for sustained chain engagement while remaining machinable for bore finishing operations.
Tooth profile and pitch dimensions conform to ISO 08B-1 simplex chain standards, ensuring accurate mesh with any compliant 08B roller chain.
Nineteen tooth count options from 12T to 30T let you dial in the drive ratio you need without sourcing a custom sprocket or compromising on geometry.
Each sprocket is turned and hobbed to consistent tolerances, so chain wrap, pitch circle diameter, and hub dimensions stay within spec across the full tooth range.
Tooth geometry matches standard 08B simplex sprocket profiles, making these a direct replacement for worn sprockets in conveyors, gearboxes, and light industrial drives.
| Chain Standard | ISO 08B-1 Simplex |
|---|---|
| Chain Pitch | 1/2" (12.7 mm) |
| Roller Diameter | ~8.51 mm (0.335") |
| Inner Plate Width | ~7.75 mm (0.305") |
| Tooth Count (T) | 12T – 30T (see variant options) |
| Bore Type | Pilot Bore (finish to shaft size) |
| Material | 45# Carbon Steel |
| Finish | See variant options |
| Hub Diameter | See variant options |
| Hub Length | See variant options |
| Overall Width | See variant options |
| Pitch Circle Diameter | See variant options |
The tooth count determines your drive ratio. Divide the driven sprocket teeth by the driver sprocket teeth to get the ratio. For example, a 12T driver paired with a 24T driven sprocket gives a 2:1 reduction. Select the tooth count that achieves your target output speed or torque from the Size dropdown above.
This sprocket is designed for ISO 08B-1 simplex roller chain with a 1/2" (12.7 mm) pitch. It is not compatible with duplex (08B-2) or triplex (08B-3) chain, nor with ANSI #40 chain, which shares the same pitch but has different roller and plate dimensions.
A pilot bore sprocket ships with a small through-bore (the "pilot") that is smaller than your shaft. You take it to a machine shop or use a lathe to bore it out to your exact shaft diameter, then cut a keyway if required. This gives you a precise, custom fit that a fixed-bore sprocket cannot provide.
45# carbon steel (equivalent to C45 / SAE 1045) has a tensile strength typically in the range of 600–800 MPa and is well-suited for light to medium-duty industrial drives, conveyor systems, and power transmission applications. For heavy shock loads or highly abrasive environments, consider a hardened or alloy steel sprocket.
Carbon steel sprockets are susceptible to surface oxidation in humid or wet environments. For indoor or dry applications, standard lubrication is sufficient. For outdoor or washdown environments, consider applying a corrosion-inhibiting lubricant regularly, or contact us to discuss alternative material options.
Yes. These sprockets are compatible with standard 08B chain tensioners and idler arrangements. Ensure the idler sprocket tooth count and bore are matched to your chain and shaft, and that chain wrap angle on the driver sprocket remains above 120° for reliable power transmission.
The pitch circle diameter (PCD) for a roller chain sprocket is calculated as: PCD = Pitch ÷ sin(180° ÷ T), where Pitch = 12.7 mm and T = number of teeth. For example, a 20T sprocket gives PCD = 12.7 ÷ sin(9°) ≈ 81.2 mm. If you need the exact hub and OD dimensions for your specific tooth count, contact us to confirm before ordering.
