MIMF

Hello, this works for me.

I'm roughing out a bone nut. After sizing it to width & depth, here's how I cut string slots. After marking off the locations, I stick the nut to the edge of the bench with double-stick woodturner's tape. I cut a very fine starting groove with a saw. Then I select a string of suitable gauge (the intended gauge or a slightly smaller size), and then I dip it in automotive (silicon carbide grit) valve grinding compound, and then saw away. I used to chuck the string in a jeweler's sawframe, but now I just wrap it around my fingers. Occasionally, I'll take it over to the sink and give it a rub-n-scrub with handsoap and an old toothbrush, to see the depth of cut. Then refinements can be made.

>As always, develop a technique that is new to you, on scrap material.<

cool idea, my first files were hacksaw and coping saw blades ground down.

I've used strings in a jeweler's saw, but the abrasive would speed things along. Since I use a zero fret, I'm not aiming for accuracy of depth, just a clean and appropriately sized slot.

With strings or wire you have to be really careful that the front edge of the slot does not end up with a downward slope. If this happens you will not give solid support to the string at the critical leading edge which will lead to buzzing.

Exactly so.

To avoid that, I place the peghead side of the nut away from the bench, so that the sawing motion is initiated away and downward from the fret side of the nut. The fret side is cut during the final strokes The cutting action, i. e. approximate pressure and number of strokes, is similar to using a file. When cutting the final strokes, clean away any blobs of compound, slow down, and check frequently for a good fit.