Issues with pre-fretting overhanging part of fretboard?

[Tom Frei]

I think I would rather pre-fret my Martin second fretboard, the first 7 frets or so. I've read luthiers doing this successfully, or that it may bend one way, or? Any issues to look for?

[Michael Lewis]

Tom, would you please re read what you wrote and rephrase it so we can understand it?

[Greg Robinson]

Michael, I think I understand, let me have a shot.

Tom, if you're going to pre-fret part of your fretboard, why no do the whole thing? I do this whenever building from scratch, and whenever I have to re-fret a fretboard I've had to remove for some reason. The fret tangs will force the fretboard into a back bow, and you can then clamp it into a forward bow overnight to get it flat again, this also helps to seat the tangs better and makes the frets more solid.

If you have to fret after the fretboard is attached to the neck, or you are doing a re-fret, the force exerted by the tangs can cause the entire neck to back bow, sometimes more than string tension can pull out. It's much more difficult to deal with an entire neck that has back bowed than it is to do the same with a fretboard.

[Tom Frei]

Ah, good, ok, thanks. About how much on a 25.7 scale, will it bow?

[Greg Robinson]

Depends on the wood (how dense it is), the width and condition of the slots, and the frets (how wide the tang is, how sharp and wide the barbs are).
When fretting ebony or rosewood, I usually find that jacking either end of the board up with 1/2" blocks and clamping down at about the 10th or 12th fret all the way down to the bench overnight, mostly seems to come out pretty close to dead flat.

[Tom Frei]

Ok, thanks

[Clay Schaeffer]

Hi Tom,
When I "pre fret" a fingerboard I leave out the first fret and the tenth or eleventh fret and drive a small brad through the slots. The brads can be used to align the fingerboard and to keep it from slipping out of place during gluing. I pull them out after the glue has dried and then insert the two remaining frets.

[Tim Allen]

I also pre-fret, leaving out two frets and using brads (actually, pieces of sewing needle or hard wire) to keep the fretboard from shifting when gluing. Just a note: especially when using ebony fretboards, pre-drill a hole for your brad or whatever that's nearly the same diameter, or you risk splitting the fretboard. DAMHIKT.

[Ron Belanger]

I also fret before I glue the fingerboard to the neck. It is vital to insure your neck and fingerboard gluing surfaces are dead flat. I use a fret arbor press with the StewMac fret press caul set. Works like a charm. Then I follow a similar procedure to Greg to get the fingerboard flat. It works for me.

[Barry Daniels]

Just to give credit where credit is due, Gregs process was first described here by Mario Proulx several years ago.

[Greg Robinson]

Damn, I normally remember to give credit, but must've slipped my mind this time. Barry is correct, I first heard this procedure described by Mario Proulx, thanks Barry! And thanks Mario!