I visited Jose at JFK Precision Products. He is a very nice guy and was very helpful. He is the (one and only) guy who makes these things. He apologized for the error and gave me a replacement right away. They appear to be a very old manufacturing shop, that is past their prime. I kind of feel sorry for them, because I'm sure they've been hit hard in the last decade, just like many other US small manufacturers. He mentioned that the owner passed away about 5 years ago, and he took over the operation. He's been a machinist there about 25 years I guess. A lot of the parts are done on manual machines, but they are running some things on CNC lathes (Ganesh and Seiki). There didn't appear to be an inspection process in place, but I may not have seen it. He mentioned that the part in question used to be just turned, and now they turn it, then grind the OD.
The bad news is, the new part is still pretty far out, about .007. See video below.
The vibration is not as bad now, but it is still there. The .015 size difference between the OD of the draw tube and the ID of the locking ring is also an issue. The closer does not seat the same way each time you close it. See video below:
I spoke with a representative at Tormach about this, and he said the larger bore in the locking ring is to allow the tube to easily pass through when on different lathes it needs to shift in relation to the pulley somewhat to be indicated in. I'm not sure that makes a whole lot of sense to me. Once it's indicated in, I see no reason for the bore in that ring to be any larger than about .003 larger than the draw tube.
So, if I end up re-making these pieces, what material should I use?