100B29 Sprocket With Stock Bore 1.3125" Stock Bore This 100BS9 sprocket features a

This 100BS9 sprocket features a 1" finished bore with a key-way and two set screws

Stock Bore: 1-1/2"

If the chain gauge falls through and goes to the next size up it's time to replace your roller chain

100BS12 2 3/16" Finished Bore Sprocket Dimensions

Something else that is notable about this 08B15 sprocket is that it fully meets all ISO Standards

100B29 Sprocket With Stock Bore 1.3125" Stock Bore This 100BS9 sprocket features aThis 100B29 sprocket is a durable, high quality, and precision sprocket with 29 hardened teeth. Sprockets that have hardened teeth last longer and are much more durable than those that don't. Something else that is notable about this 100B29 sprocket is that it fully meets all ANSI Standards, which insures proper contact between the #100 roller chain and sprocket thus preventing premature wear or breakage. This sprocket is also fully black oxide coated