I just very recently got an 8" RT, set of indexing plates and a tail stock. I intend to make more gears than what my spin indexer allows. My first attempt at gears was duplicating one of the change gears on my lathe. 30 teeth, hub & keyway. I hand ground a cutter to use in a fly cutter by eyeballing an existing gear. Broached the keyway with a sharpened pc of key stock on the lathe. Made an arbore for a 5C collet to drill blank size & whittled away.
I put the finished gear on the lathe to test run. Worked fine but I don't know how long an aluminum gear would last. It was just an experiment to see if I could pull it off. Didn't want to take the time to do it in steel.
Next thing I want to try is making a splined shaft and matching gear to slide on the shaft. I haven't figured out how to broach the gear yet. More YouTube university time needed. If all else fails I'll try to do it on the mill using the RT indexing and moving the mill table in X&Z, spindle locked.