GERRY - My old Parker sweeper had cast iron internal gear teeth on the front wheels, and sintered teeth on the little drive pinions. I took the wheels off every year or two and greased them. In order to get the sweeper to sweep leaves I had to put some weight on the drive wheels. A piece of 3 inch channel iron with a 100+pound steel block improved it's performance tremendously.
It finally suffered terminal problems, the thin tubing that made up the rear frame to hold up the basket and casters broke in two. Too thin to weld, too complex to replace with something home-made. Still had the original brushes, drive wheels, etc.
It really did a nice job on sweeping grass clippings & leaves, but it was a L-O-T of work sweeping leaves. One fall, year or two after we moved here SON & I swept leaves SIX weekends in a row in the fall. He pulled the sweeper w/129, I pulled the cart w/72. Three sweeper's full made one cart full, Some places SON would have the sweeper full in 40-50 feet. SON spent a LOT of time waiting on his Dad to unload. If we didn't mulch the leaves the sweeper filled up in less than 20 feet some places.
Next time I get to Rantoul, IL for Half Century of Progress, I'll have to look for Agri-Fab's plant.
The glass filled Delrin gear that is the main spur gear that drives an RC-10-GT Associated R/C race truck runs against the either sintered pinion gear on the clutch bell, or a hardened cut gear welded to the clutch bell. After 8 or 9 years of racing, we were still using the plastic gear that came with the kit. The clutch bell over-heated once the first day or so we raced it and melted two gear teeth a little, but it was still good to race with. Associated made two different tooth count gears, 70 & 72 IIRC, we did buy the other size to make gearing changes, but always used the stock gear that came with the kit when needing that range of gears. We had clutch bells for that truck from 12 teeth to 18 teeth.