We must all remember that the drive train on Carriers goes back a long way and has a war at the end of it! The evolution of parts both reflects design improvements and production compromises. I suspect that the sprocket shown is an early version used until someone had the bright idea to simplify the manufacturing cost and time. The loyd version on mine and a 1941 dated example I´ve seen are flat, just like Martyns photos. All my sprockets are shot, worn to within an inch of their life by the Belgians post war. I too need a NOS example to get the profile from as I need to get four made. Will anyone in the midlands lend me one or a .dwg for the lazer cutting chap? I know Martyn hasn´t got one as his are bolted to the UC
The simplified sprocket doesn't positivly guide the track on a UC, but for some reason when Loyd used the standard sprocket they added the guide plates to run against the outside track horn as discused earlier in the thread, the other horn on the track runs an a deep groove cast into the drum. The sprocket is attached to the drum by bolts and special curved steel plates on the back side of the drum sprocket flange, thus on a Loyd the sprockets are bolted from the front and there are no nuts, the curved plates are tapped instead.
PS. Loyd brake drum is with the pattern maker now...worn sprocket is on the workshop floor, came off quite easly once Martyn had used his heavy duty socket set to split the drum from the hub! (thanks for the help)