Lemme get this straight. You attached a 4 jaw Myford lathe chuck to an R8 Arbour?
If so, WOW! Can't wait to see you use it!
Yep, you got it.
I'm
NOT expecting great results. Quite frankly I'm expecting a lot of chatter, and would be very (pleasantly) surprised if there wasn't. But it's the only way I can finish the OD of my belt grinder drive wheel with what I have right now. Well, it's not the only way, but one of 3. None are the best. I can either do it on the myford itself, and make some special tooling to reach the OD. I can mount it on the actual motor, clamp the motor down on the mill table with lathe tooling in the spindle/on the head and run the motor (slowly), while using the mill to feed. I can't run the mill spindle because I'd need the VFD to run the grinder motor....OR I could try this adapter and see how it works, and maybe learn something. Between low range and the vfd I can slow it right down to nothing, so it should be fine safety wise. I really don't think it'll be any worse than the myford itself with cantilevered tooling to reach the OD.
I thought of this a few months back while designing it, and was going to machine one because I didn't figure this would actually be a thing. But when browsing ebay for a Myford backing plate for my 5c collet chuck I found this (and a bunch of other myford adaptors that I also bought) and thought it was cheap enough to take a punt on it. I'm always willing to try something if there's a learning opportunity, or justification for a new tool purchase.

. Quite frankly it's a ridiculous enough idea that I'm intrigued by it's possibilities

. I HAVE done turning with both manual and CNC mills, so this isn't much different.....
Of course, the 4th option was to buy a bigger lathe....Believe me, I've been looking. Almost bought a 10" atlas for dirt cheap last week, but my only justification would have been to turn this wheel, and then I would have flipped it because I have no room for it, and want' something bigger and better than an atlas when I do get a new lathe. I would not have kept it and sold my Myford.