This is a difficult part; there are many operations and a correspondingly high possibility of making an error that will force a start-over.

A step-by-step pictorial is in an earlier post of 10 June 2013, “One Piece Frame”.

All the critical dimensions requiring concentricity are cut with one chucking on the “grip”, the smaller diameter extension of the material blank that you see in the photo. The “grip” is axially long enough that the outer diameter surface of the part clears the jaws of my chuck.