Bracket in place ready for jack and outer cup.
Possibly the worst guitar jack plate idea in guitar construction. The Vintage Telecaster jack is held in place by a bent steel plate with a hole in the center for the jack in it. It is jammed in place by it's 4 corners. The jack goes on the inside and the cup goes on the outside with a nut holding it all in place. When the wedged metal plate comes loose so does the jack. Those fine folks at StewMac have come up with a wonderful tool that collapses the loose plate and then holds the plate in the correct position while compressing it back into place. It is the best way I have seen to re-do an original installation. There are some alternatives like a flat square or football jackplate or even the new inset one the screws in from the outside you see here in the photo.