Of course, the wheel and hub could be removed, the work completed and then the wheel and hub could be remounted. That's a lot of work and there are many ways to get it wrong. But then I wouldn't get to describe the nifty way of using dead centre turning to solve this problem. Prepare a special female centre for the pinion end by drilling a hole in the end of a brass rod just .01mm larger than the pivot three times deeper than the pivot is long. Make certain the pivot is a slip fit in the drilled hole and that the hole itself is on centre.
Hobby shops sell wheels for wooden toys that work well.
Drill a hole in its centre just big enough to be a press fit on the OD of the female centre described above. Select a piece of annealed steel or brass wire of a convenient size. This wire will be used as a driving dog to turn the workpiece. The length will be determined by the distance from the face of the disk to the wheel crossing. Use a very sharp lozenge shaped graver to cut a female cone using the hole as its centre.