I'm confident they can be chucked up with a 4 Jaw. It's pretty common for NAPCO guys to chuck the OE caps up to cut holes for locking hubs with no Issues.
Cutting a circular hole in the center is entirely different than cutting off the outer rim of a stamped hub cap. You could have a .100” runout at the rim and still cut a perfect hole in the center only it would not be perfectly centered. Chucking a stamped hub cap and getting it to run true enough to slice the outer cap from the inner is a horse of a different color. True, a four jaw is the way to do this as you can bring up some of the low spots to get it to run somewhat true. Some of the issues you may encounter are:
1) You need to apply enough pressure from the jaws to keep it from spinning or worse, being ripped out of the chuck. Trust me, you don’t want it to be ripped out from the chuck. If your lucky enough not to get hurt, it usually destroys the part. You may not be able to apply enough pressure to keep it from spinning without distorting it. Remember its only stamped steel, more than likely no more than 18 gauge (.048”). Let me explain. As you put more outward pressure on the jaws, you will be pulling in the portion of the cap between the jaws creating new low spots making it more difficult to get it to run true. If I was cutting just the center for a hub, I would not be concerned with temporarily distorting the rim of the cap. More then likely it will return back to it’s original shape.
2) Assuming you do get it to run somewhat true, say for example <.010” at the rim, the inner and outer cap might be in contact with each other especially where its rolled over. By the time you cut thru the low side of the outer cap you could be cutting into the high side of the inner cap.
3) When you are finishing cutting thru the outer cap, it will not cut thru evenly. It will break thru the high spots first, followed by the average, then thru the low spots. At the point it is ready to fall off, the tool bit might grab the cap and rip it out of the chuck. This is especially true if you have only one low spot. I would stop before this happens and finish it with a Dremel and a thin cut-off wheel.
One more caution: Turn the cap slowly. If it does get ripped out of the chuck, the slower you go, the less damage it will do.
I’m not saying it’s impossible but as a career machinist with over 27 years in a shop, I’m saying it will not be easy and could be down right dangerous.
