1978 Fender Stratocaster with backbowed neck issues!

[Michael Burton]

So I have this 1978 Fender Stratocaster that I am refretting. It has a maple neck. The damn micro tilt after years of use, has kinked the upper fretboard up (a rising tongue condition). There was a buzz in the upper register. With the truss rod almost loose, it looked like it had 0.012" of relief at the 12th fret, but it didnt. The extra rise in the upper fretboard made it look that way.
With the customers permission, I sanded away the warped wood from the 15th to 21st fret so its flat. Keep in mind that I never took any wood off the neck below the 15th fret. Just the tongue where it's supposed to be either flat, or have a bit of fallaway. But now there is only 0.007" of relief at the 12th fret with the truss rod completely loose. It turns out that this neck has a lot of back bow.... usually it's the opposite with older guitars I figured.
I'm thinking of adjusting the truss rod so its around 1/2 to 3/4 of a turn in its travel and sanding the fretboard flat..... then I figure I can loosen the truss rod and give it relief as it needs.
Have you dealt with this issue before? And does this sound like a reasonable correction?

[Michael Burton]

Seems I can't edit my post...?
Anyhoo, The first pic is off the upper fretboard with the rise! The second pick is of the backbow in the neck. The third pic is of the upper fretboard after I had sanded the rise and made it flat. Here is an extra photo lol. I used a 7-1/4" radiused sanding block. Why it uploaded upside down I dont know. The pic is not like that in my files.

[Walter W Wright]

looks like you're dealing with it nicely (how ya liking that metal stew-mac jig? i just upgraded to one myself recently and am lovin' it)

i might have tried to address some of those issues with heat-clamping first to see if maybe i didn't need to sand so much away after, but i dunno, the jury still seems to be out on the longevity of that kind of fix.

as for the micro-tilt, that likely had nothing to do with the rising tongue/neck kink thing; look at your first picture, the kink is happening around 14, i.e., before the neck even reaches the body pocket!

if you look, you'll usually find the kink happens right where the neck transitions from round to square in the back, it's a "concentration of stress" failure right at the transition.

[Michael Burton]

Thanks for the reply Walter.

It's a weird scenario... the neck backbows very easily, yet when adjusted as straight as I could get it, the neck had an upward bow in the upper register.

Thinking about using a fret barber and filing off the barbs on new frets to loosen the neck up a bit. Then maybe it might go into a bit more relief. If not, I'll pluck em and sand it a bit.

This neck has no separate fretboard. I wonder if heating will do much. I read that if there is a separate fretboard, the heat/clamp will slip the glue joint so the neck will straighten out, then can be held straight with fret compression after.

Where this is one piece maple will heat do much I wonder?

As for the neck jig, I love it. Seems to be way better than other means of supporting the neck during fret leveling with just hands. A bit of time to jig a guitar, but worth the time it takes for the convenience and precision during fretwork afterwards.

[Walter W Wright]

i'm skeptical of the "glue joint slipping" theory of neck heating; that may be a side effect but i don't think it's the main factor.

if you heat up wood and bend it it will in fact conform to a new shape and stay there, that's how acoustic instrument sides are made. 

[Russell Vance]

Hi all,

Acoustic sides are less than 1/8th inch thick, soaked and hit with steam.  Maple Necks  are an inch or so thick and to get them to bend, and stay bent with a bit of heating and some pressure is a difficult ask.  Anything is possible I suppose.   Fender necks kink at the 14th and no amount of wishing will get them to lay flat once they have gone.

Pull (slide) the  frets - may as well as you are halfway there anyway,  see what the board looks like, pre stress the neck with the trussrod, lock up the jig to that setting, sand it flat with a 20”” caul,    Program  some drop away (3 to 5 thou) from the 15th onwards and refret with something like 50 x 80 wire to give you some post Refret wiggle room.   The bigger wire choices need to be scrutinised regards fret barb width and depth but the principles are the same. 

The principle is to accept the neck has done whatever it was going to do, dressit a bit and then final fix with a consistent fret set across the whole span.

Thats what I know. 

Regards,

Rusty

[Michael Burton]

Thanks Rusty:

So yea, I have already got the upper fretboard flattened. I may sand a bit of fallaway as well. As for sanding in some relief into the neck (since with truss rod totally loose I only have 0.007" @ 12th fret), does it sound reasonable to adjust the truss rod to roughly 3/4 of its travel and sand it flat there? At 3/4 of a turn there is about 0.015" of backbow (gap at the 2nd fret) which seems like an awful lot compared to what I normally see when a truss rod is roughly set at that stage.

Then I figure I should get plenty of relief when the truss rod is loosened? Plus I know I can still have headroom to get it straight and even backbow slightly if I adjust the rod to its max travel....?

[Russell Vance]

Hi Michael, 

thats the basic idea which you have got already, it’s too hard to make a call as to the exact settings to achieve a result as you wish. I usually scare myself with being a bit too fine especially with bigger dimension tangs compressing the neck. However as you are fretting in an area which won’t compress a lot you are pretty safe.  Around 12 to 15 thou with no stress and unfretted is what one of the big West Coast “super strat” guys machines into his boards in the build process (if that info is useful).   Go slow and check yr logic while doing so.

Regards, Rusty