Concave fingerboard on vintage guitar

[Craig Bumgarner]

Just to be sure, no guitar, vintage or otherwise should have been made with a fingerboard that is concave across the board, right? It is warped, right? 1916 Maurer acoustic, cheap model but nice in its own way. I'm assuming the fingerboard was originally flat, no radius, and it has warped into a concave across the frets, both the board and the frets, about .010" - .012". I could probably take it out of the frets, but they are small and it seems the right thing to do is pull the frets, plane the board and refret. Thoughts?

[Jason Rodgers]

Whaaaat? Show pictures.

[Michael Lewis]

Craig, without seeing this guitar I have to say this is only a guess, but you are probably correct. I have seen this in several old instruments. Be very careful with the fingerboard as it is most likely very fragile. You will know if you pull a fret and see lots of chips come up with the fret. Take a look at the seam between the fingerboard and the neck to see if there is any gap. Or is there binding covering that area?

[Craig Bumgarner]

Here ya go.

Roger on brittle fingerboards. Some of the old French guitars I work on have fingerboards made of pear wood dyed black, they crumble to bits when pulling frets, no way can they be saved. No a big deal as I'm usually replacing the fingerboard anyway. Rather not do that here though. This one looks like a mahogany fingerboard or maybe some kind of rosewood from a hundred years ago. I'll probably try leveling the frets first to see how that goes, they are currently .038" high, probably have to take ~ .010" off the ends. Sounds pretty low, so if it does play well, then I can always still pull them and just hope the fingerboard does not fall apart in the process.

Regards gapping under the fingerboard, yes, there is a little in the middle, around the 5th - 9th frets.

[Alan Carruth]

Ebony seems to have higher 'shrinkage hysteresis' than most woods, and particularly more than most neck woods. It loses a bit of width with every full cycle from dry to wet and back again, and pulls the top of the neck concave. That's one really good reason to make fingerboards with at least some radius. It's darn near impossible to do a clean barre on a concave neck. Pull frets, radius (a little!), and re-fret, and you usually end up with a happy customer.

[Michael Lewis]

If the fingerboard is in solid condition you might think about removing it and reinstalling it. Since it has a gap already it might come off without too much mayhem. An instrument from the teens will be glued with hide glue, which can be aided by applying alcohol to the glue. I think the alcohol sucks any moisture from the glue and breaks down some molecular bonds. This is how violin and bass fingerboards are removed. Stick a blade in and add a few drops of alcohol and wiggle the blade. Add a few more drops of alcohol and wiggle the blade, then it starts going 'poppity crack poppity crack' as you wiggle the blade and the glue lets go, not the wood. It shouldn't take a lot of force . . . . . unless you are tearing wood fibers.

I really don't like to suggest to someone to remove a fingerboard because of some of the issues that can arise in the process. However, sometimes it is the best option, particularly if it comes off easily.

[David King]

I have to agree with Michael. If the fingerboard is flatsawn I'd just replace it and put one with a 30" or greater radius. Get any neck angle and bridge height issues taken care of at the same time.

[Trevor Gore]

If you end up pulling the frets, heating them with a soldering iron first often helps them come out and reduces the chipping. Even with non-oily woods like mahogany, the gunk collected around the frets over the years can be used to advantage...