You remove the parallel(s) after the part is secured in the chuck jaws. The advantage of the magnetic stops is that you don’t need three hands.All too easy for parallels to come loose and fly out at you or get jammed up as the come loose, definitely not a safe thing to do.
thats like mine. I have 2, one thicker than the other. I call it a spider. I just face it every once in a while, mine are beat up, and I have a new chuck coming , so will have to make new ones. I don't understand @ChazzC 's need for 3 hands, I've never found it difficult on a 3 jaw.If I’m understanding correctly these used to be called chuck spiders, at least that’s what I knew them as. Easy enough to make — I made one for the 3-jaw and one for the 4-jaw. On mine there is a set screw between each of the slots so you can dial it in in the event your chuck face isn’t true. Or maybe I’m misunderstanding the purpose?
This isn’t mine, just a screen grab to show the design…
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