I just realised I already have a pop-rivet dimple die. Looking at it, I don't understand when this tool would be useful. The female die is attached to a "nail" (I call it a nail because that's what it looks like) that goes up into the pop riveter. The male die slides down over the shank of the nail and the pop riveter squeezes the dies together by pulling up on the nail.
From what I can see, to dimple anything you have to have enough clearance on the opposite side to be able to poke that nail through the hole to be dimpled. This is quite impossible in a narrow flange. If I had enough clearance to get that nail in there, I would certainly have enough clearance to fit the yoke in there to use a squeezer for dimpling.
Also, there is an extra "nail" included with the dimple die, this one not attached to anything (no female die attached). What is this extra nail for?
Am I misunderstanding the functioning of this tool?