Archtop with bowed neck

[swingtoneman]

I have an archtop with a bowed neck when up to pitch--advice needed.

When up to pitch the neck has quite a bad 'up bow' (Concave--arch dipping away from the strings). The truss rod is fairly tight and I do not want to tighten more as fear of the truss rod breaking. When the string tension is off the fingerboard is straight. Does the fingerboard have to come off and level the top of the arm? The guitar in question is an 'Azalea' archtop.

What would you do?

How can you tell if the truss rod is a single or double truss rod?

[JohanAbrandt]

I have an archtop with a bowed neck when up to pitch--advice needed.

When up to pitch the neck has quite a bad back bow. The truss rod is fairly tight and I do not want to tighten more as fear of the truss rod breaking. When the string tension is off the fingerboard is straight. Does the fingerboard have to come off and level the top of the arm?

What would you do?

How can you tell if the truss rod is a single or double truss rod?

Often you can fix a back bow by combination of heat and clamping, lots of vids on you tube. If its a good guitar and you dont consider yourself really handy find a luthier

[John A.]

I have an archtop with a bowed neck when up to pitch--advice needed.

When up to pitch the neck has quite a bad back bow. The truss rod is fairly tight and I do not want to tighten more as fear of the truss rod breaking. When the string tension is off the fingerboard is straight. Does the fingerboard have to come off and level the top of the arm?

What would you do?

How can you tell if the truss rod is a single or double truss rod?

Back bow= convex arching toward the strings. Up bow = concave arch dipping away from the strings. If it’s back bowed, you should loosen the truss rod. If it’s up bowed and the truss rod can’t be tightened any further, take it to a luthier. Possible fixes include heat treatment and refretting.

[Marty Grass]

I had a Gibson L-5 that was heated with an excellent response. You need a pro I believe.

[deacon Mark]

There are things you can do but no, actually the neck being straight without strings does not mean it will hold that way. What kind of guitar is it? A picture is worth a lot. Sometimes when working on guitars like this I use my home invention setup to manually adjust the truss rod. I use blocks are first fret and where neck meets the body. I have 2 blocks set on the neck fingerboard side. Then I have a piece of rock maple the length between the two wooded blocks. I then take a jorgenson clamp and pull the neck up creating artificial backbow in the neck, buy applying the clamp in the middle of neck. Then I will adjust the truss rod and tighten it against the nut. Sometime you might need to add a washer to the nut if that is possible on your guitar. What this does is take the tension and work of the truss rod adjustment away from actual adjusting. Doing this the truss rod will simply move up and hopefully hold the neck in place. It is best to overshoot the mark as you can then back tension off the truss rod.

I hope this makes sense but it is very easy to do. Sometimes I simply do this on guitars that I think the truss rod is reaching the end of its limit for adjustment even though things are good to go. To tell you the truth except in a few rare circumstances over the years this has worked fine. Mostly on cheaper guitars with pencil thin necks being a issue and also on basses. I have at times also had situation where I have had to do this a few times in a row. I take all the tension off the rod then manually add it back with jig setup. What is does is allow the neck a new set point.