Fingerboard Curl

[Doug D]

what causes the overhanging portion of the FB to curl up causing the FB relief to be excessive?

I recently workd on a 40s Kay that had nearly 10mm or more of 'relief' as a result of this. or so it appeared.

using a straight edge, I could see that the neck portion appears to be straight and if I put pressure on the overhang with the heel of my hand, I could temporarily flex it back to 'normal'.

this was the original BRW board as best I could tell.

[Ken McKay]

Humidity...time...wood tension.
Or
excessively scooping the board.

Take it to your luthier for a repair and get it playing well.

[Doug D]

thanks.

the customer already picked it up. it was in for a different reason. I was just wondering about the causes.

thanks agian.

[zeytoun]

was it an ebony FB, or a softer wood?

EDIT: Just saw "BRW" (Brazilian rosewood, right?) This isn't the sort of thing you'd expect from an ebony FB, is it?

[Doug D]

yeah....

I caught a chuckle from seeing the traces of 'ebonizing' over that beautiful rosewood

[james condino]

Most of the old Kays that I see with the infamous potaoto-chip fingerboard extension are due to the cut of the board, not the material. Slab or flatsawn wood tends to do that much more than quartersawn boards, regardless if it is ebony or Brazilian rosewood. A lot of times the lower priced models used Brazilian that was a lower flatsawn grade. Even that grade today commands a premium price with guitar builders.

j.

[Gary Lynch]

My bass has the opposite issue. The neck is warped convex, not concave. My luthier thought that was not so bad because the string pressure may pull it back after years? So the end of the fingerboard actually bows downward if you look down the neck. It plays well, set up with low action and all notes growl like they are in heat. Not everybody's style but I own three and this is my growling machine.