Leaf Chain finished bore sprockets provide increased avoidance of shaft slippage over minimum simple bore sprockets. Finished bores allow for the roller chain sprocket to go larger loads with an increase of accuracy.
Toronto Gear Functions produces ready-to-ship completed bore sprockets that are manufactured with precision and are fast and simple to install. Our catalogue features a variety of finished bore sprockets that may match many precise overall performance requirements.
Toronto Gear Works stocks steel finished bore roller chain sprockets for #25 (0.250” pitch) roller chain. We share these metal sprockets in tooth counts ranging from 9 to 72. Our completed bore sprockets with a 0.500” bore or smaller are supplied with two set screws. Our finished bore sprockets with a 0.625” bore or greater have a typical keyway and two set screws. The keyway can be centered on the tooth and the arranged screws are located over the main 
element at 90 degrees.
Steel finished bore #25 roller chain sprocket part numbers could be determined as follows:
25BF + Tooth Count + “x” + bore size.
An example will be 25BF72x1-3/8. That is for a #25 roller chain. It includes a “B” design sprocket which means that it has a hub. It includes a finished bore of just one 1.375” and it provides 72 teeth.