My curiosity doesn’t run to $150 worth either.

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Having another look at the patent over at shows what I thought was a pin though the shaft isn’t, the dashed lines just mean they aren’t claiming a patent on the screwdriver slot (which I think is fake anyway).? That explains why the top lines are dashed and not solid like they should be.? One must remember to RTFM more often.

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I still think everything is pressed together in one form or another, that’s the best from a manufacture & assembly view.

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There’s not a lot of metal to bang a shaft into, but that sort of thing hasn’t stopped watchmakers, although they have the advantage of peening over the back of the shaft to lock it in which doesn’t happen on the ring.? It’s hard to tell how thick the ring section actually is.

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Plenty of other ways to do it, more if you’re the accident prone type.? One old lathe trick to use a knurl to raise the surface a bit, the shaft is now ‘oversized’ and can be pressed in.? Something like that would be the easiest way, it reduces the accuracy needed to make the parts a bit, you’re sliding (or less) fit is now a friction fit.

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For a small diameter shaft like this you could probably hit the end of it with a punch to flare it out a bit. ?Or like they use to make rivets (and jewellers still do), you drop a pin onto a hole in a plate leaving a small bit protruding above the surface.? Then you hit it with a hammer.

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If you like things to be more complicated carpenters have what they call wedged blind tenons, like this: .? The wedge causes the tenon to expand, locking it.? That’s a ‘get it right the first’ joint, once in it ain’t coming out.?

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That would be a good choice for this ring, you just need to cut a slot in the shaft.

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I’ve seen things that work like a collect in reverse (it has name, I can’t remember it), the shaft has a hole & slits like a collet.? A ball bearing slightly over the hole size is the ‘wedge’, you drive in the shaft, the ‘collect’ expands slightly and everything locks together.? Like the blind tenon that ain’t coming out either.

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I doubt it uses a wedge, but if you were after low tolerance machining (typical hobbyist) that’d work well. ?Most of the parts are all that accurate, in some of the videos you can see the gears moving up & down on the shafts.? Not that you’re want a close fit there given the amount of crap it’ll collect.

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If you can whip up the tooth cutter, the rest probably wouldn’t be much of a challenge.? It just rack & pinion around a ring, how hard can it be? ?:)

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Tony

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