Straightening neck of vintage Gibson J50 with large amount of upbow

[Andrew Hann]

Hi,

I have acquired a 1955 Gibson J50 which was in an unplayable state. It's not original, in that the top has been refinished and the bridge replaced at some point in the past. The neck had some 25/1000th of relief with the truss rod already tight - the truss rod nut had compressed the wood at the headstock end leaving a fair amount of thread showing. So someone in the past maxed the truss rod out in an attempt to get the neck straight, without success. A nut and saddle were installed very poorly ( they were far too high) which made the guitar unplayable.

I tried the trick of looensing the truss rod, lubricating the thread, and making a couple of spacers to fit over the rod in the truss rod pocket. Then clamping the neck into a backbow before tightening the truss rod again. However, even tightening the nut again as far as I dare, there is still around 13/1000th of relief.

The frets ( not original, but original spec) are in good condition save for one or two which are not fully seated causing a couple of buzz spots. I lowered the nut and saddle so the guitar plays reasonably at this stage, albeit with a fair amount of relief. 

I'm thinking the only option for getting a straight neck is to remove all the frets, get the neck as straight as possible (in neck jig) and sand the board flat, taking off as little wood as possible, then re-fretting but using some fret compression to pull the neck out of it's upbow.

I'm not sure about heating the neck as a method - I get the feeling that this is a stubborn neck that may not respond to this treatment- but I don't know as I've not heated a neck before.

I'm a fairly recently trained luthier - done a number of fret jobs on new(er) guitars - but not come across such a tough neck bow problem, and its a vintage guitar ( albeit not all original) with the potential to sound and play really well.

I wondered if anyone has had a similar problem, worked on old Gibsons like this, and could let me have their views on my proposed course of action.

Many thanks! Andy

[Andrew Hann]

I hope not Allan - a last resort for me I think! 

[Dean Sibley]

Hi Guys,

 I have not contributed for a while due to bereavement but regularly peruse this site with interest. It surprises me no-one has mentioned the steam option on most irons. I used to restore antiques & was given an old Ibanez Seville - from the bowels of an antique dealers storage room. @ the nut the bass string was about 3mm higher than top E - probably due to someone putting steel strings on it.I removed fretboard clamped it ( slight opposite twist) with 3 blocks under neck & used a $2 charity shop iron on steam & cotton settings. My first neck adjustment - self taught with no reference(computer) or advice. Replaced fretboard - problem sorted in couple of hrs. That was 5 yrs ago & it is a very nice " behind the couch" guitar to play while having coffee or jamming with old blues albums. For 2 yrs prior to this I occasionally would put it on the bench & tried various techniques with zero result - with the fretboard on.

  I also use a common household floor steamer together with old bone handled sheffield steel bread & butter knife heated by holding it on the iron every few minutes, to remove fretboard. Steam prevents shrinkage but still need to be carefull with celluloid inlays.

 For both tasks the ironing was done freehand not clamped.

Recently retired so just about to start using Braz. rosewood, mahogany, cocobolo, cuban mahog, Honduran walnut & more which I bought 30 yrs ago! & have been lugging it around ever since. Important lesson here for newbies & younger lads - allocate 20 - 30% of your machine/tool allowance to the finest & rarest wood you can get - even if you only buy 1 small stick.& DON'T touch it. When you get old it would be frustrating to have fine, rare skills, fully equiped workshop (is that actually possible?)  & only radiata pine & particle board to work with!

Happy new year to all.

Dean

[Dean Sibley]

Hi Guys,

 I have not contributed for a while due to bereavement but regularly peruse this site with interest. It surprises me no-one has mentioned the steam option on most irons. I used to restore antiques & was given an old Ibanez Seville - from the bowels of an antique dealers storage room. @ the nut the bass string was about 3mm higher than top E - probably due to someone putting steel strings on it.I removed fretboard clamped it ( slight opposite twist) with 3 blocks under neck & used a $2 charity shop iron on steam & cotton settings. My first neck adjustment - self taught with no reference(computer) or advice. Replaced fretboard - problem sorted in couple of hrs. That was 5 yrs ago & it is a very nice " behind the couch" guitar to play while having coffee or jamming with old blues albums. For 2 yrs prior to this I occasionally would put it on the bench & tried various techniques with zero result - with the fretboard on.

  I also use a common household floor steamer together with old bone handled sheffield steel bread & butter knife heated by holding it on the iron every few minutes, to remove fretboard. Steam prevents shrinkage but still need to be carefull with celluloid inlays.

 For both tasks the ironing was done freehand not clamped.

Recently retired so just about to start using Braz. rosewood, mahogany, cocobolo, cuban mahog, Honduran walnut & more which I bought 30 yrs ago! & have been lugging it around ever since. Important lesson here for newbies & younger lads - allocate 20 - 30% of your machine/tool allowance to the finest & rarest wood you can get - even if you only buy 1 small stick.& DON'T touch it. When you get old it would be frustrating to have fine, rare skills, fully equiped workshop (is that actually possible?)  & only radiata pine & particle board to work with!

Happy new year to all.

Dean

[Dean Sibley]

 I should probably mention for beginers  that steam may adversely affect lacquer finish. Both repairs mentioned above, the Ibanez had been incredibly poorly refinished & I stripped it & repolished with shellac & one repair was to replace a mahog. neck on a 12 string I have had for 40 yrs - my first neck replacement - learned a lot about shaping, truss rod installation etc.

Sorry about the double vision above - haven't used computer for a while.

Dean

[Robbie Collins]

If you use a neck jig to straighten the neck and then level the fretboard you'll still have a bow when you take it out of the jig. Rather than straightening the neck with the neck jig, use it to recreate the bow with the truss rod adjusted half way, then flatten the neck by taking off wood at each end of fretboard. This will leave you with a flat neck with room for adjustment after restringing.