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When a worn or undersized sprocket is causing chain skip, premature wear, or misalignment in your drive system, finding an exact-fit replacement matters. These 08B roller chain sprockets are designed for engineers, machine builders, and serious DIYers who need a dimensionally accurate, drop-in solution for standard 1/2" pitch (08B) chain drives.
Each sprocket is machined from 45# medium-carbon steel, offering a solid balance of hardness and machinability. Tooth counts range from 10T to 32T, and bore sizes span 10mm to 40mm with matching keyways from 4mm to 12mm — covering the most common shaft diameters used in conveyor systems, agricultural equipment, and industrial machinery. Overall sprocket outer diameter scales with tooth count, typically ranging from approximately 45mm (10T) to 170mm (32T).
Typical applications include replacement sprockets for conveyor drive shafts, gearbox output shafts in packaging machinery, and power take-off assemblies in light agricultural equipment. The keywayed bore ensures positive torque transmission without slippage — critical in cyclic-load or reversing-drive scenarios.
Medium-carbon steel provides the hardness needed for tooth wear resistance while remaining machinable for custom bore modifications if required.
Twenty tooth-count options let you dial in the exact drive ratio your application requires, from high-speed small sprockets to slow, high-torque large sprockets.
Pre-cut keyways (4mm, 5mm, 6mm, 8mm, 10mm, or 12mm depending on bore size) ensure positive shaft engagement and eliminate rotational slippage under load.
Tooth profile and pitch geometry conform to the 08B standard, ensuring correct chain engagement, reduced noise, and extended chain life.
Dimensionally matched to standard 08B sprocket specifications — select your tooth count and bore size for a ready-to-install replacement with no additional machining required.
Suitable for conveyors, packaging lines, agricultural drives, light industrial machinery, and DIY power transmission projects using 1/2" pitch chain.
| Chain Standard | 08B (ISO 606 / BS 228) |
|---|---|
| Chain Pitch | 1/2" (12.7mm) |
| Tooth Count (Type) | 10T, 11T, 12T, 13T, 14T, 15T, 16T, 17T, 18T, 19T, 20T, 21T, 22T, 23T, 24T, 25T, 26T, 28T, 30T, 32T |
| Bore Size Range | 10mm – 40mm (see variant options) |
| Keyway Width | 4mm / 5mm / 6mm / 8mm / 10mm / 12mm (matched to bore) |
| Material | 45# Medium-Carbon Steel |
| Outer Diameter (approx.) | See variant options (scales with tooth count) |
| Hub Style | See variant options |
| Finish | See variant options |
| Quantity per Order | 1 piece |
The tooth count determines your drive ratio. Divide the driven sprocket teeth by the driver sprocket teeth to get the reduction ratio. For example, a 10T driver paired with a 30T driven sprocket gives a 3:1 reduction. Match your required output speed and torque to select the correct combination. If you are replacing an existing sprocket, count the teeth on the original or measure the pitch circle diameter.
Both 08B and ANSI #40 share a 1/2" (12.7mm) pitch, but they are not interchangeable. 08B (ISO/BS standard) has a roller diameter of 8.51mm and inner link width of 7.75mm, while ANSI #40 has a roller diameter of 7.92mm and inner link width of 7.85mm. Using the wrong sprocket with your chain will cause poor engagement, accelerated wear, and potential chain derailment. Confirm your chain standard before ordering.
Measure your shaft diameter precisely with a caliper and select the matching bore size. The keyway width is pre-matched to the bore: 10–12mm bore uses a 4mm keyway, 14–16mm bore uses a 5mm keyway, 18–22mm bore uses a 6mm keyway, 24–30mm bore uses an 8mm keyway, 32–35mm bore uses a 10mm keyway, and 38–40mm bore uses a 12mm keyway. Ensure your shaft has a matching keyway cut to the same width and depth.
45# medium-carbon steel (equivalent to C45 / SAE 1045) has a typical tensile strength of approximately 600–800 MPa in the normalized condition. It provides good wear resistance for the tooth flanks and sufficient toughness for cyclic loading in standard industrial and agricultural drives. For very high-shock or abrasive environments, consider whether a hardened or alloy steel sprocket would be more appropriate for your specific duty cycle.
45# carbon steel will oxidize when exposed to moisture without protection. For outdoor or washdown environments, apply a chain lubricant or anti-corrosion coating to both the sprocket and chain regularly. If your application involves continuous water exposure or corrosive chemicals, consider stainless steel sprockets instead, as carbon steel sprockets are best suited for dry or lightly lubricated indoor industrial environments.
Yes. These 08B sprockets are well-suited for light-to-medium duty conveyor drives, packaging machinery, and agricultural power take-off systems that use 1/2" pitch chain. Verify that your existing chain is 08B standard (not ANSI #40), confirm the shaft diameter and keyway dimensions, and select the tooth count that matches your required drive ratio. For heavy-duty agricultural or high-cycle industrial applications, ensure the sprocket tooth count and bore size are confirmed against your OEM specifications.
The sprocket bore is pre-cut with a keyway slot, but a key (the rectangular steel piece that fits between the shaft keyway and the sprocket keyway) is typically not included. Standard parallel keys are widely available at industrial suppliers. Match the key width to the keyway width specified for your bore size (e.g., 6mm key for a Bore 20 Keyway 6 variant). Ensure the key length does not exceed the hub depth of the sprocket.
