truss rod repair/installation... How do I do it?

[Zach Schryer-Lefebvre]

Hi everyone,
I have an old Harmony flattop acoustic, jumbo-style. The major issue with it is the action. I tried to take the fingerboard off, but it seams they used a glue that doesn't soften with heat.
I thought installing a truss rod from the bottom of the neck may work, but is there a better way to fix it?
I believe it is a dovetail neck joint... but the fingerboard is glued solid onto the top..
Hope you can help me!
Thanks,
Zach

[Chuck Tweedy]

Cool the engines there Zach - You need to figure out what is wrong first before taking this old beast apart.

First, the truss rod is NOT used to lower the action. It is used to adjust relief.
The first, and most simple thing to do is lower the saddle.

Questions:
1) Have you checked the relief (do you know how to?)
2) Is there some saddle sticking out of the bridge?

Extremely bad relief can cause high action, however that is not usually the problem.

EDIT: Oh, and why are you trying to take the fingerboard off??

[Zach Schryer-Lefebvre]

Right, right. You're right. I already lowered the saddle - it helped but the action is still almost 1/2" at the last few frets closest to the bridge. What do you suggest I do then? I was thinking the ideal thing to do would be to touch up the angle of the neck joint... But that glue just is not going to come apart (the glue holding the fingerboard to the mahogany top).
I've run out of ideas, but you're absolutely right; the problem isn't with a bow in the neck - it is definitely a relief issue... Any thoughts???
Thanks a bunch,
Zach

[Greg Robinson]

Zach, there seems to be some confusion in terms here.

Relief is the amount of "bow" to the neck. It is adjusted with a truss rod, or on guitars without, the relief is traditionally adjusted by planing the fretboard to achieve the desired level of relief with string tension applied.
Relief is measured by placing a straightedge on the fretboard with strings tuned to pitch, and measured from the top of the fret at approximately the middle of the neck to the straightedge (usually around the seventh fret).
Normal relief ranges from dead flat (no gap between the straightedge and the seventh fret) to 0.02" at the extreme, but average is 0.01" and is a good compromise for most playing styles.

You don't need to use a straightedge to measure this either, the string themselves make a good straightedge too. If you put a capo on the first fret to eliminate the nut as a factor, and use one hand to fret the string at the fourteenth fret, you have a free hand to measure the relief.

So, can you measure the relief of your neck, and report back? It sound like it is not a relief problem, but rather a neck angle issue, which would require a neck reset if the saddle is getting too close to the top of the bridge already. When you report back we'll be able to give you more advice.

[Mark Swanson]

The problem could be- and most likely is- a combination of too much relief and a bad neck angle. I have worked on a lot of these Harmony guitars. The older ones have either no truss rod, or a non-adjustable metal rod in the neck and are marked "steel reinforced neck". If there is an adjustable rod then you should be able to adjust the relief, but not the neck angle. As others have explained, those are two different things. So get the neck straight first and THEN worry about your neck angle. If you have non adjustable neck and it is warped then you'll need to address that.
The glue on these guitars should loosen with heat and moisture. Using just heat will not wwork and you need to get some moisture in there too.

[Steve Senseney]

To elaborate a little further on disassembly--

It will be more difficult to get moisture under the fingerboard. Many times (most times) you will need to use a very thin knife or spatula, drip a little moisture into any cracks or separations you can find, and then apply heat also. Work slowly and sometimes the Fingerboard will come off nicely, or not come off nicely.

If it does not come off nicely, you may have to replace it. This is often a good choice, as it might need new frets and you could upgrade the quality of the fingerboard.

To remove the neck (the dovetail joint), you will need to get steam into the joint.

To do this, you either drill through the heel, drill through a fret slot, or drill through a fretboard marker into the space, and apply steam.

When you have a good steam source and are in the correct spot, the neck joint can release fairly easily in 5-10 minutes. If it is not loosening, you may not be in the right spot, or have enough steam. Then re-evaluate.

[Eddie McRae]

A little about the history of Harmony which might help you understand what you're up against..... Harmony was one of the leading "house brand" manufacturers along with Kay. They were based in Chicago and not only did they produce instruments with their own name, they also produced instruments for other companies that subsequently renamed them as their own. For the times, it was true mass production. So, as you can imagine, they were made rather cheaply. When I first started learning to play slide about 20 years or so ago, I bought and aquired a bunch of the archtop acoustics. Harmony, Kay, Montclair, etc and what I soon figured out was that none of them were worth the expense and trouble of trying to fix. The most common problems were extremely bowed necks and extremely warped tops. Both of which cause excessively high action and both of which, I imagine, were a direct result from the way that most all of them were built. Having said that, they are neat to have if you can get one setup properly but I found on most all of mine that it was quite a task to accomplish. I still have several of them now that I never even tried to fool with. But as already stated above, your most-likely problems will be excessive neck bow, bad neck angle, or possible top warpage creating an incorrect bridge height. As Mark mentioned, the majority of them either had no trussrod or a non-adjustable steel bar in the neck as the one in my picture shows. Also, most all had a glued dovetail neck joint which I found on most of mine had not been fit very well. I'm not disagreeing with any of the above info when it comes to handling your issues but I will say this. I only managed to get one of these into nice playable shape and I realized after the fact that it hadn't been worth my trouble. It required me removing the neck and clamping it into a corrective position for a while to remove the bow and then I actually went as far as installing a double adjustable trussrod. I also had to remove the top (which was already separated anyway) and repair some of the bracing. And of course, during this process, adjusted neck angle and refit the dovetail joint. And to me, it simply wasn't worth it considering the actual value of the instrument. Anyway, just my 2 cents. I'll post a couple of pics that hopefully will give you better insight as to how their made since one of them has the fretboard removed and shows the reinforcement rod along with the neck joint. Good Luck!

[Zach Schryer-Lefebvre]

Okay... Relief: I checked the relief (actual relief) and it is at approx. 0.015"
That would mean that the neck relief is not that bad... But the action is still way too high.
Eddie I think you're right with everything you said- I got this guitar at Value Village for $4. It was in horrible shape; the joints holding the sides and back and top together were separating and there were bad cracks up the back and top. The top was warped (which I managed to mostly fix) so some of the braces had come apart from the plate(s).
It looks 100% better and is playable but out of tune in the higher frets. I lowered the saddle after lowering the overall bridge height and deepening the saddle slot...
Now I fear some neck joint work is needed...
I'll attach a picture (if it works)
This is my first repair... I didn't have any expectations for it turning out, but so far it is far better than expected.

[Eddie McRae]

Well, you picked a good one to learn on then. They make great guinea pigs. If you screw something up, you really haven't lost much. If you've determined that the neck is straight and you still have an excessively high action, then my guess would be that the neck has pulled upward at the neck joint and it most likely needs a neck reset. And if that's the case, here are my thoughts..... There's a thousand ways to skin a cat, but if it were me, and I was considering this to be a learning and educational experience, and IF I had decided that it was worth the trouble to continue on, then I personally would convert it to a bolt-on design and in the process, work the neck angle issue out. Basically, in a nutshell, I'd remove the dovetail from the heel and I'd fit and glue a block into the dovetail in the body making it solid. I'd then determine the needed neck angle and plane, sand, etc. the heel until I achieved that angle. From there, I'd drill the body and neck for bolts and install inserts into the heel. And depending upon how the fretboard extension is supported, I might even make it "bolt on" rather than gluing it back down on the top. The point is, you're gonna have to remove the neck anyway and chances are that the dovetail joint won't be a great one.....so you might as well take an extra step and make it a more practical instrument if you're going to all that trouble anyway. And in the process, you'll be learning about a bolt-on system. Again, though, this is just my opinion.

[Steve Senseney]

Eddie is giving good information.

You will learn a lot doing this.

After it is all apart, it would not be too hard to shim and correct the original dovetail. Another learning experience for you.

[Mark Swanson]

I'd steam that neck off, don't make it a bolt-on. It won't be that hard to fix it right, you will learn a lot about how a dovetail works besides.
Let's not knock these guitars too badly! They aren't bad. Some of them are, just a bunch of bad plywood....but some are really not that bad at all. This guitar you show is solid sapele, not plywood! I had one exactly like it once, it was my first guitar! I have a really hilarious photo of me playing it when I was 15.
So, if you take an objective look, you have a solid wood guitar...you pay pretty good for one like that today. The main issue with these is the substandard construction, and if you fix that you have a pretty nice guitar for the money so I feel they are worth the bother if you feel like taking it on.
Too bad you jumped in and did all those repairs before posting and asking, or I wwould have suggested to you that you take the top off and re-brace it, Martin-style. If you do that, you will be rewarded with a very good sounding guitar. I've done that quite a bit and some of the Harmony guitars I have finished up that way would fool many a Martin freak into believing they are hearing their grandpa's old 000-18!
It's all just wood, name aside, so if you put it together right it'll be a goodie.

[Zach Schryer-Lefebvre]

Awesome, thanks for the positive feedback guys!! I will steam the neck joint apart and take it from there wherever I have to. The sound and resonance is actually impressive out of it so far, I'll go with you on this one Mark, doesn't sound cheap although it would have been a good experience to re-brace the top... Oh well.
Thanks again!
I'll let you know how it goes, and I may be asking more questions,
Zach