Sprocket : A sprocket or sprocket-wheel is a profiled wheel with teeth, or cogs, that mesh with a chain, track or other perforated or indented material.The name 'sprocket' applies generally to any wheel upon which radial projections engage a chain passing over it. How does a chain and sprocket work? A chain is used to connect two sprockets.The other sprocket is the driven sprocket. Motion and force can be transmitted via the chain from one sprocket to another, therefore from one shaft to another.Chains that are used to transmit motion and force from one sprocket to another are called power transmission chains Hardened teeth with keyway on centerline of tooth. Black oxide finish. Setscrews (2) are on keyway at 90 degrees. Bores in inches. Our Related product Bailey Idler Sprockets: 3/4" Bore, 4.33" Outer Diameter, 12 Teeth, 80" Chain Size, Zinc Plated, 133774 Bored to Size Sprockets: 1 1/4" Bore, 4.01" Outer Diameter, 11 Teeth, 80" Chain Size, Hardened Teeth, Black Oxide Finish, 133734 Bailey Bored to Size Sprockets: 5/8 Bore, 40 Chain Size, 11 Teeth, 2 OD, 133504