Furnished content.
(from Lumberjocks.com)
Since I started making fretted instruments – dulcimers, ukes and banjos – the most often asked question in “how do you cut the slots for the frets?” It started by laying out frets with a 24” Vernier caliper from Harbor Freight and cutting them by hand with a fret saw. This worked but was time consuming so I upgraded to a circular fret saw from StewMac used with a crosscut sled. However, a template was still needed to improve accuracy and repeatability. Templates and manufactured jigs are pricey, but pre-slotted fretboards of common wood such as maple are relatively inexpensive from StewMac or LMI and make great templates. The last part of the solution came from a workshop by Jason Romero who described using a thin piece of sheet metal as an “indexing” device. It took while to figure out a way to incorporate this into the crosscut sled. The addition is nothing more than a milled piece of fir with a .023” slot attached to the crosscut sled with Rockler fence clamps. A feeler guage fits the slot and can be easily lifted up and set down in the slotted template which is attached to the blank fret board with double sided tape.
I make most of my fretboards from Jatoba as well as Wenge and other relatively dense hardwoods. For information, the maple template was ripped in half for convenience and to have a spare.