Apologies for resurrecting an old thread but to me, as an old bicycle mechanic, the photo from the Kurtz archives seems to be showing the crown race from a bicycle headset race (the bearing cup that sits on the top of a bike's forks, where it goes through the frame)
I'm sure that there could have been an old bike (or anything that uses a similar bearing system - a trolley / cart etc) or something kicking around on set that would have easily been butchered for this spare part. It would have been a very easy and cheap part to source.
Here's a photo of a more modern bicycle heat set - it's the bottom crown race cup that I think might have been used for this part - though no idea of a specific make / model.....
View attachment 849007
What do you reckon?