MIMF

Just thought I would post and ask for feedback. I made two guitars with ebony nuts - I really like the black appearance of ebony. The ebony used was quite old - probably 20 - 50 years cut, and in small pieces (I got it from a knife maker who used it for handles). Both were set up normally with the bare clearance over the first fret when fretted at third fret, and both lost clearance after around 12 - 18 months. The second, third and fourth strings would buzz out on the first fret. All I can really do is replace with bone, for long term reliability, yet I know that ebony has been a useful nut material for centuries. Any ideas? Frankly, I wonder if the fretboard swelled or something equally mysterious. Rosewood on one, birdseye maple (which has proven to be a really unstable choice, I have dressed the unbound fret ends at least 6 times) on the other.

You could try building up the ebony with ebony dust and superglue as is done with bone when the slots are too deep. If the color is what you want then using a synthetic (richlite, micarta, etc.) might be another way to go.

Early on in my career I tried a few ebony nuts and didn't like the softness or the tone. Been using bone ever since.

Ebony is fine for violin family nut and just ok for fretless basses. At the very least get ahold of some African blackwood for a fretted instrument nut. If you want extra hardness align the grain vertically. Lignum will also do but it's not nearly as dark.

Round wound strings will saw through ebony over a fairly short time. Violins and electric guitars tend to use flat wounds, so it's not a problem for them.

I have an old Gibson C-1 with an ebony nut/string spacer and zero fret. If you like the look of the black nut, perhaps using it as a string spacer nut with zero fret would give the look you desire on future construction.