Crooked fret slots on bowlback

[aethelynt]

So I've got a very problematic fretboard on this old Weymann bowlback that's in disrepair, as you can see from the photos...

The fret slots are crooked! I'm wondering what the best course of action for repair would be here. Filling the slots and recutting? Replacing the fretboard entirely? How would the binding affect possible repairs?

I also wonder about the frets. The original frets are far gone, and I don't know the logistics of using modern frets on old instruments like this one. Perhaps frets could be cannibalized from another old bowlback that's in decent condition? Or maybe it wouldn't matter if the fretboard needs to be replaced altogether, in which case modern frets are acceptable?

Obviously this kind of problem is best solved by a luthier, but this mandolin is not "worth" repairing professionally, so I am basically using it as a learning experience. Thoughts and advice are greatly appreciated! Thank you :)

[rcc56]

The easiest fix is to replace the board with a nice new one that's been pre-slotted by CNC. It would be far less work than filling and recutting the slots on the existing board, which would indeed require removing the binding and a very accurate sawing system. There are several places that will sell you a pre-slotted board. LMI is one of them.

There's no need to hunt down antique fret wire for this mandolin. Wire with a crown that's .053" wide by .037" high would be a reasonable size for a bowl back. You can pre-fret the new board before you install it if you're crafty enough.

The touchiest part will be removing the old fretboard. I use a 1" x 5" 25 watt heat blanket, available from McMaster-Carr or MSC, and a Harbor Freight router speed controller to regulate the temperature. Whatever you use, heat slowly, and don't rush the lifting process. You can use just a drop or two of water on your lifting tool from time to time if you need to. If the existing board is on the thin side, you might want to go a little thicker with the new one. I think I would go for 5/32" on a bowl back. I prefer to use hot hide glue for fingerboards.

Go to www.frets.com and start reading some of the articles under "Items for Luthiers" before you buy anything or attempt to start the repair, so you'll have some idea of what you would be getting into. There are a lot of need-to-knows when you replace a fingerboard, and several tricks that can make your life much easier.

I also recommend that you purchase and read Hideo Kamimoto's book "Complete Guitar Repair."

If you're in the Southeast and want some training or want someone to pull the board for you, you're welcome to pm me.

[sunburst]

Sometimes fret slots are cut perpendicular to one side of the 'board rather than square to the center line. It looks like that is what happened here, though there also seem to be a few randomly "off" fret slots.
IMO, the easiest fix is; slant the bridge to match the frets and play it.

[Tom Haywood]

The first mandolin repair I did some years ago was to replace the fret board on an old turn of the century bowl back. The ebony looked about like yours, and the frets were not quite as bad as yours. The thing sounded inconsistent, but it had that characteristic bowl back sound. As rcc56 pointed out, removing the fret board was a royal PIA. When some dried-out brittle pieces broke off, there was no going back. I purchased a blank fret board to have a proper thickness, and a fret saw because I couldn't find anyone who was set up to slot a 13" scale. I purchased modern sized mandolin frets, because the fret saw cuts modern size slots. I created a spreadsheet to calculate the fret slot locations, which turned out to go to 4 decimal places, requiring a really good ruler, magnifying glasses and, finally, estimation to 2 decimal places and a very steady hand to start the slots correctly, along with a very sharp marking tool and a thinner saw blade to start the slots. I created a little jig to place against the side of the blank to guide cutting slots before shaping the blank to fit the neck. As you might imagine, it took a good bit of time to install 17 frets. Then came the issue of how to clamp the entire board for gluing to the neck and top.

The end result was a MUCH better sounding and playable mandolin. It was quite rewarding to achieve that result. That mandolin hangs on my wall, and it is still rewarding to look at that nice fret board.

Now, for the rest of the story. Having completed the fret board and repaired a crack in the top, I strung it up with ultra-light strings and started playing. It was really quite delightful. Until. About 3 weeks later, the top began to sink under the fret board. There is no bracing there to prevent rotation of the neck. That's when I concluded that these bowl backs, as a general rule, were not designed and constructed to last very long. Hence, it's a nice wall hanger.

Nevertheless, the experience of replacing that fret board and cutting the fret slots has been very useful on several occasions repairing or building other mandolins. Still, I would have the board slotted by CNC whenever possible and check the math (distance) afterwards to be sure they got it right.

[aethelynt]

Thank you so much everyone! I can't express how valuable this information is to me. I really appreciate it!