My CNC is still down, still have the itch to build stuff so today I built a fret bender.
Sort of an industrial version, used stuff I had laying around.
Slotted the 3/8 plate with a laminate router mounted to the fret saw I just built.
The lower bearings are mounted on ground shoulder bolts with a 75# die spring behind them to keep them pushed against the head. They mount into threaded holes every 7/16" apart.
The carriage for the drive roller hold a pair of 3/8 id bearings for smooth rotation. made the brass drive roller out of a hunk of 1/2" brass plate. cut it out with a hole saw and dressed it out on my vertical lathe (read cheap import drill press) with a file. I cut the slot for the fret tang with a hacksaw(while I spun it in my lathe,err, drill press), after I had it cut I realized I should have centered it in the stock instead of half the fixed bearing thickness, but it works.
I covered the adjustment slot with Teflon glide tape. The button head screws that keep the carriage centered have brass bushings to make them fit nicely in the 3/8 adjustment slot.
A carriage bolt with a handle provides my downward pressure, return springs mounted in the side keep it against the carriage bolt when the pressure is released.
An old piece of angle aluminum extrusion made a nice bench mount.
With the drive roller fully retracted I can fit up to 3/16" stock in there. I don't have any fret wire to bend right now, but I bent up a mess of coat hanger. I can go as small as 11/16" inside radius with the fixed rollers on the inside holes and the drive roller all but touching them, to I'm guessing about a 10' radius with the rollers mounted to the outside and the drive giving a slight pressure.
I got around all the parts except a couple small diameter flange bearings to make a pickup coil winder tomorrow if I still don't have my Z axis ball screw back from the machinist.