Tritan 40BS21H 3/4 Roller Chain Sprocket Finished Bore Keyway SS 40 collectible

A 21-tooth steel sprocket for 40-series roller chain

This finished-bore sprocket fits single-strand 40 chain with a 1/2-inch pitch and presents a 3/4-inch bore that already includes a 3/16-inch keyway. Two set screws lock the hub to the shaft without additional machining. The black-oxide coating protects the steel from surface corrosion during storage and light service.

Mounts directly on a 3/4-inch shaft to drive

The 3.355-inch pitch diameter and 3.62-inch outside diameter sit on a 2 3/4-inch hub that projects 0.716 inch through the bore, leaving one face clear for guards or adjacent components. Because the bore is fixed at 3/4 inch, the sprocket cannot accommodate larger or smaller shafts without replacement. Builders needing a different bore size or a double-strand hub must select another part.

Supplied with two set screws and a machined keyway

The included set screws and 3/16-inch keyway eliminate the need to source separate fasteners or cut a key seat, reducing assembly time on conveyors, packaging equipment or farm drives. No lubricant, chain or tensioning hardware is bundled, so those items must be ordered separately to complete the drive.