Originally Posted by 63rickert

I wish I had a good answer. Have tried to best of ability and thrown some time at the question and not come up with good answers. I have found that as late as 1900 cycling companies were making capex investment in lathes for bearing manufacture. So I will say your bearing is 20th century and can't do better.

Bicycles were the killer app that made bearings a thing. Before bicycles arrived it was done with bushings or with journals run in Babbitt metal. Or you just didn't design it. When bearings were made it was an extremely special one-off. Then bicycles created a demand. Bikes wanted little bearings, not the specials for locomotives. Everyone was working on a way to supply bikes with bearings and no one had anything better than cutting them. Might be done on an automatic screw lathe but that was still basically one at a time, slow and expensive. And crude. Tech was changing practically daily in 1890s. Other factor in play was after the huge boom in 1892-3 bikes did not completely remain fashionable. They were expensive as all heck and the industry needed fashionable gentlemen to be spending cash. Those guys stop spending when it stops being cool. Then automobiles happened.

The real kicker is that in Germany they were grinding bearings in bulk as early as 1879. They had been making marbles since early eighteenth century and figured out same process worked with steel just as with marble or agate. But outside of Germany no one knew. One of the reason German 'oldtimers' are used and ridden a lot more than American bikes of similar vintage is they always had good bearings. The rough lathed bearings beat the bikes to death.