Hey, you two, pick on Bog's time is it?
Unfortunately, Bandit doesn't want anything to do with me at the moment, that is why I am having trouble coming up with new ideas.
Anyway, back on track to put you straight, but first, this turned up this morning, I had forgotten to order it when I ordered the hobs.
A nice shiny 8mm arbor that fits the hobs perfectly. So part way along with the project.

Back to reality, and thinking INSIDE the box.
As I have already explained to John in private and everyone else now, plus having to come up with reasons for not using what has been suggested. I have a lot of thinking time on my hands at the moment, but not a lot of machine time, so even though your ideas are good, I have come up with my own. The main problem was getting the cutter made, and John has solved that for me.
My way of thinking.
WHY make life difficult for myself when I have most of the items available at my disposal? It also keeps the costs well down.
The first, accurate indexing. I have my dividing head to do that,
Putting an accurate cut on. I have the compound slide off the lathe to do that. Plus if I really wanted super accuracy, I can just plug the compound read head into the mill display, and I could, if I wanted to, be working to the nearest 0.00005" (or even more accurately if I decide I want to swing the compound round a little).
So what else needs to be done. The slotter, which has to be made anyway.
Then a support block for the compound to mount it onto the mill square and at the correct height.
Much easier to make than some sort of indexing bits for the lathe.
Can you think of anything I have forgotten?
Does the well know phrase or saying spring to mind - KISS.

Do I hear any mumblings in the background? Or are we going to extract the urine out of Bogs once again.

Bogs Bandit