If that doesn’t work I have sometimes drilled a hole with a tiny drill bit through a fret slot and tried to measure the length of the bit at the point when I feel it break through.

I prefer fretting a new dulcimer after the body is assembled so I can’t wham it very hard and the same applies when refretting.

On a new dulcimer I thin the tang of the fretwire using a jig I got from Stew Mac. It is basically a small vice with files in the jaws and you can run the tang of the fretwire through it and thin it very easily.

I get the tang to a thickness by feel that will fit into a fret slot with light, careful hammering (more tapping than hammering) after putting some “super glue” on the tang.

This way I get some light compression in the slot as well as the glue keeping things tight and well seated.

The other option is to widen the slot; something I have done on refrets but prefer not to do when fretting a new instrument.I have a backsaw with a kerf I achieved by filing the sides till enough set was removed to give me a slightly wider fret slot.I then proceed with the light hammering and gluing to install the frets.

Many luthiers widen fret slots with a rotary tool. I haven’t tried this myself.

Let me know if you have any other questions and let me know how it turns out!

Doug

What timely article. I bought what I believed to be a nice mountain dulcimer a few years back for my wife. Since the purchase it has developed a muted tone when fretting above the 5th fret along with two cracks in the soundboard. Some frets don’t note at all. The issue is the frets toward the bridge are hitting the string when fretted at the 6th fret on to the bridge. Frets 1 to 5 work as expected with nice clear tone.

After working the frets a bit, I managed some improvement but it is clear another issue is at work. I looked closely at the fingerboard and the frets and determined there is what I consider an excessive amount of relief in the fingerboard. Excessive being .035 between the 6th fret and the straight edge placed on the fret from 1 to the end. The fingerboard is also quite uneven and tilted toward the low D string. My opinion was that the only resolution was to remove the frets, level the fingerboard and refret.

Having no experience or knowledge of the workings of a dulcimer I am leery of that task to say the least. I am comfortable fretting guitars and mandolins so I’m not a novice. When you fret a dulcimer do you use a hammer? It seems an arbor press is out of the question the way it’s made. For example, when I put a finger inside the sound whole I can feel the inside of the fingerboard is hollow. Is that typical? Can you comment on your fretting process? The last thing I want to do is further damage an already cracked soundboard.

I’m tapering from the nut to the bridge but mostly between the 4th and 8th frets. The relief is very slight, a little less than the thickness of the top string (.010.) I actually prevents buzzing because the strings don’t hit those frets when playing in the lower positions where the action is lowest.

The fingerboard itself is flat side to side.