Actually, I've had this project done for a while, I made this at Techshop a few months ago. Anyway, here's how I did it.
First, I started with my disk.
Step 1: Bending Arm
Add a piece of DOM tubing that is bored for a bronze bushing, and clean it up with a nice shoulder.
The shoulder presses in to a piece of 4140 that has a slot cut in it.
Finally, this piece is all assembled with just a quick weld.
Step 2: Guide Blocks
In the future, the guide blocks will be set up to be pushed for/aft on a spring, should I need to bend a shape that isn't round.
Step 3: Center Shape Mandrel
This serves as a mandrel for the wire to be bent against.
Step 4: Assemble and Use
Now I just have to spend the rest of my life making an assortment of tooling for it.