Something isn't right here. Please see "black smith how to make a hollow hole punch". In economy of motion, You can just hammer out the hips in the forge then bore the shaft, for the spinning wheel orifice, and when the drill bit pops through to the hips, the second hole is produced. But that's not what's going on here. This is all cottage industry, so we're probably looking at 4 separate examples where no one figured out you can do this. Or, boring with a lathe isn't how its done.
The one example available of a guy building a spinning wheel that details the building of the flyer shaft and orifice assembly. He takes it to a guy with a stick welder, presumably to weld the spindle portion to the orifice. Its hard to tell because the footage is grainy. But in the flyer the orifice does not need to be connected to the spindle shaft. The can be separate pieces, but this makes it harder as you have to center everything up with those as separate components. But it shows there's difficulty sorting this out, if people where willing to go to the lengths of not joining them and instead fighting tolerances to a possible wobbly flyer. If modern cottage is saying theyre 2 pieces by stick welding them, examples of not joining them are suggesting theyre 2 pieces, Not using economy of motion to create 2 holes for the price of one in these examples are saying theyre 2 pieces. My gut is telling me theyre 2 pieces. The orifice portions is looking alot like a black smith nail header that fits into a hardy hole for forging heads on railroad spikes. This makes the orifice portion with no lathe. the second hole in the shaft looks obviously forge punched.
But then how to join them? Braze or bronze welded or forge welding? Perhaps I'm wrong and its a single piece thats orifice is forged like a blacksmith nail header thru a hardy hole then punch the second hole.
Im not buying the lathe hypothesis. If you had a lathe, you'd be making brass cannons. These are cottage industry junk items that might fetch $5. Like you could knock them out quickly with low quality tooling.