Pete.
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- Kent, UK
To machine an oval you need to move the tool relative to the workpiece as it turns. Getting it off centre will still machine a circle, but it won't be concentric with the centre of the hub.
But being basically a ring if you over-clamp the part one way on say jaws 1 and 3 then snug up 2 and 4 even to the same tightness you'll end up with an out of round part when it's released.