Machining down Borbet A Centre Caps issue

[Shieldsy94]

Hi, i've got some Borbet A wheels in 14 inch and they have a smaller centre cap diameter than the 15inch and above (18cm compared to 14.9cm needed).

How would people go about lowering the size on them safely?

Asked a few locals about lathing it down but said no because they can't be gripped on. Any thoughts?

Thanks

[Teknomaz]

Most things can be gripped within the jaws if you have the right ones of course, or you can just trap it between two face plates ( one on the headstock and one on the tailstock) on a turning lathe and centralize it as it spins> I do this all the time when machining down blanks that have no spigot hole.

[Shieldsy94]

I'll have to see if its possible with the lathe. Its not that large a lathe to be honest so not sure if i can get it to grip.

[Teknomaz]

My lathe is out of action at the moment, but if you can hang on for a week or so I can get you some pictures of how I would set it up. Do the jaws come out of your lathe? We use threaded carriers instead of jaws sometimes so we can screw up flat plate tools which is ideally what you need if the jaws will not hold it.