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The gear is centred to the shaft but the lobe is off. This is where the four jaw chuck and a dial indicator are used to centre the axis of the lobe. If you don’t have a four jaw, one jaw in a three jaw chuck can be installed one turn of the scroll out of synch of the other two. This will give a rough non adjustable offset but shims can be placed under the teeth of two of the jaws to get a finer adjustment.
The prop shaft wasn’t threaded on either end so I used a rotating chuck in the tailstock to keep pressure on the cam while it was being turned. The piece of copper tubing in my last photo was used to get the clearance needed to get a good unobstructed cut.