I nasmuch as there were at one time a couple hundred windmill makers in the U.S., I’m only going to talk about a few of the more common ones, their similarities and differences.
Windmills have been around for a very long time, but self-oiling units are, in the whole scheme of things, fairly recent arrivals on the scene. For a long time, oiling was accomplished by owners or employees climbing up the tower and physically filling eitheriron area above the bearing in question, filled with cotton waste. Oil was poured onto the cotton waste, the theory being that oil would slowly run down and keep the babbitt at least slightly lubricated) or the grease cups (which were filled with “hard” oil, the cap replaced and then screwing the plunger down a little. This would be repeated until the cups were empty and then the process was begun again).
