Updated 3 September 2013: See the new version of the fret wire bender.
Now I can put the frets back into the fretboard on the Martin. One fret has been missing since the beginning- the 15th, the one that was removed when the neck was steamed off. It was already gone when I got the guitar, and of course the neck and body had already been separated.
Since I have to install a new fret, this was a good opportunity for me to build a fret bender. I have a couple of complete refrets waiting in the wings, and I've been wanting to build a bender for some time. So here we go.
First we lay out and drill some holes.
The slot makes one of the wheels adjustable for different radiuses.
The center pulley is made up of two 1 1/2 inch fender washers sandwiched around a 1 1/4 inch washer.
I need a thinner nut behind the center wheel - I had to use extra washers on the outside wheels to align them all. I'll make these changes when I can get new hardware. But it's functional for now.
The crank is just a casement window crank fitted to the bolt (5/16) for the center guide pulley.
Set the radius with the left-side adjustable pulley.
Pass the fret wire through, turn the crank.
Not a great example, since it's only one fret, but you can picture how you'd do this with a coil of wire for a whole instrument.
The center pulley's a bit wobby - I'm thinking of adding a brass sleeve to run the bolt through. And I had to make the slot longer than planned to compensate for the extra diameter of the outside pulleys. I'll probably change them eventually. But it's perfectly functional as is.
Took about 30 minutes and maybe $15 in parts to build. You can buy a fancy one from Stew-Mac for $90. I'd rather put that money toward other tools I can't build myself.
The Complete Martin Guitar Restoration Saga
Repairing heel break
DIY chisel for bridge plate removal
DIY bridge plate removal iron, Pt.1
DIY bridge plate removal iron, Pt.2
Steam removal of bridge plate
Bridge plate removed
Tongue brace removal
Crack repair and brace scallop
New bridge plate Pt. 1
New bridge plate Pt. 2
Patching hole in top
Final fitting of top patch
Installing carbon fiber rod
Fingerboard crack repair, Pt. 1
Fingerboard crack repair, Pt. 2
DIY fret bender tool (This page)
Refretting Pt. 1
Refretting Pt. 2
Tuner shaft repair
Neck reset - dovetail fitting
Measuring neck set with DIY jig
Gluing the neck with hide glue
Fitting bridge pins
Making bone saddle
Making a buffalo horn nut