Members Omar562 Posted June 1, 2016 Members Share Posted June 1, 2016 hey peeps, I bought a cool harmony jumbo acoustic about a year ago but i tried to move the truss rod just a bit and it broke. Here we are a year later with time to fix it. It needs a neck reset as well so i just decided to take off the neck and assess the truss rod that way. The truss rod however is strange to me, Ive seen other pictures of another truss rod that is suppose to be in there but mine is different. Its a square box like the martins and has a rod inside. i included some pictures for reference. My question is, what truss rod can i replace it with, or should I leave the square piece of metal and let it be non adjustable? I don't know where to start. Link to comment Share on other sites More sharing options...
Members Freeman Keller Posted June 1, 2016 Members Share Posted June 1, 2016 Is the relief acceptable? If so leave it - remember that lots of Martins up to about 1985 or so have non adjustable truss rods and they are perfectly fine (I have two of them). If the relief is not acceptable you can pull the frets and do whatever the neck needs - sand it flatter, compression fret it - several choices. If you decide to replace the rod then when you take the fret board off you'll see what you need to do - replace it with like kind or route the channel deeper and install a double acting rod. Link to comment Share on other sites More sharing options...
Members FretFiend. Posted June 1, 2016 Members Share Posted June 1, 2016 Places like Stewart/MacDonald or Warmoth sell new replacement trussrod assemblies. I'm guessing that removing the remains of that trussrod assembly from that neck would require removing the fretboard. The trick then is making one of these replacements fit into the existing neck. That's a big can of worms to open. It looks like the rod broke at the threaded portion. Did it? Do you still have the broken piece with the nut? It might be cost effective to take the broken rod and the nut to any decent mechanic. He should be able to weld and thread a new end on the broken rod, or fabricate a new rod. When you reassemble it, be sure to use some molybdenum disulfide (anti-seize) on the threads, and apply torque to the nut with great caution, to prevent this from happening again. Link to comment Share on other sites More sharing options...
Members Omar562 Posted June 1, 2016 Author Members Share Posted June 1, 2016 Thanks for the reply, yes the neck is pretty straight and relief is good. I think the best thing to do is to replace the rod but I would have to take the fingerboard off and then see which rod will fit.I don't know if i should do that though the neck is pretty thin, so i think might leave it in. Link to comment Share on other sites More sharing options...
Members Omar562 Posted June 1, 2016 Author Members Share Posted June 1, 2016 Yeah i don't know how Im gonna channel the neck, i don't have the tools and the neck is pretty thin. yeah it broke at the threaded portion, funny thing is there was no nut at the end unless its stuck in there. I have included a picture of it. Link to comment Share on other sites More sharing options...
Members FretFiend. Posted June 1, 2016 Members Share Posted June 1, 2016 i tried to move the truss rod just a bit and it broke yeah it broke at the threaded portion, funny thing is there was no nut at the end unless its stuck in there. Not making much sense. You said that you "tried to move the truss rod just a bit" What exactly did you try to move? Where is the piece that you tried to move? If it "broke at the threaded portion", where is the piece that broke off? Link to comment Share on other sites More sharing options...
Members Omar562 Posted June 1, 2016 Author Members Share Posted June 1, 2016 hmmm, this was a year ago. There probably was a piece but I really can't remember if there was or not. I see what you're saying. Link to comment Share on other sites More sharing options...
Members Omar562 Posted June 1, 2016 Author Members Share Posted June 1, 2016 could it be possible that the end of the square rod is threaded? i don't remember ever being a nut at the end Link to comment Share on other sites More sharing options...
Members Freeman Keller Posted June 2, 2016 Members Share Posted June 2, 2016 Several things here don't make sense. First, is the adjuster at the headstock or in the heel? Did the rod actually break off? Its fairly common for the threaded rod like Gibson and many others use to break at the headstock - Dan Erlewine has come up with a clever way to fix them - warning, its expensive (and probably not what you need) http://www.stewmac.com/Luthier_Tools...escue_Kit.html If its truly a Martin style single acting truss rod it would have a 5 mm allen nut, which it sounds like you broke off. However they are not welded on and can come unscrewed (and lost) if so, get a new nut and you should be good. Here is a picture of a Martin single acting rod (the have changed to double acting on current guitars) http://www.stewmac.com/Materials_and_Supplies/Truss_Rods/U-channel_Truss_Rod.html The rod itself is 0.472 wide and 0.400 deep, they usually have a fiber filler piece installed on top next to the fretboard. I'll go back to my earlier post and say that (1) if the relief isn't too bad and/or if it doesn't need frets I wouldn't mess with it. If it need a fret job then I would consider planing a slight amount of relief into the board and/or doing a compression refret. If the relief is unacceptable and/or the fretboard is really worn I'd pull the board, replace the rod, replace the board and refret it. I wouldn't try to put a double acting rod in it, that requires a channel 1/4 wide and 3/8 deep - won't fit in what you probably have now. Only you can decide which of these makes sense, given your tools, expertise and the condition of the guitar. Harmony's are usually considered the best guitar to practice learning repair techniques - they are cheap, come apart easily and are good candidates for neck resets and refrets. Link to comment Share on other sites More sharing options...
Members FretFiend. Posted June 2, 2016 Members Share Posted June 2, 2016 Based on the pictures, it appears that the truss rod is simply a long carriage bolt. It is inserted into the square metal channel in the neck from the glued neck joint end. The threaded end of the rod protruded out through the milled area at the headstock. There was an adjustment nut there that screwed onto this threaded end. When the nut was tightened down, it compressed the square metal channel lengthwise, stiffening the neck, and allowing for some adjustment of neck relief. Someone applied too much torque to the adjustment nut and wrung the threaded end of the rod off. About a half inch of the threaded end is broken off of the rod. Based on what you are saying, that broken piece, and the adjustment nut threaded onto it, are gone. Now, like I said, A mechanic somewhere should be able to weld and thread a new end on the broken rod, or fabricate a new rod. He'll also have to fabricate a new nut to go on it. It's not that complicated of a repair job, if it's in the right hands. Link to comment Share on other sites More sharing options...
Members Omar562 Posted June 2, 2016 Author Members Share Posted June 2, 2016 thanks for the response, the adjuster is at the headstock and it does look like the threaded part of the rod broke. Before I took the neck off it was loose inside. I see what you're saying, I got this guitar for $25 at a swap meet haha. But if I have the neck off I might as well do it right and just like [uSER=159077]FretFiend[/uSER] has been saying. I'll get a new nut, and try to fabricate the rod and do it that way. I think its the easiest way. Link to comment Share on other sites More sharing options...
Members Omar562 Posted June 2, 2016 Author Members Share Posted June 2, 2016 yes thats right, theres a long carriage bolt inside the square metal channel. as you've said, i think thats the best way. I'm going to try and replace the rod or get it fabricated and threaded with a new nut.Thanks! Link to comment Share on other sites More sharing options...
Members Omar562 Posted June 2, 2016 Author Members Share Posted June 2, 2016 This guitar had strings on it for a couple of days and it sounded so good, I can't wait to fix it up. I only payed $25 dollars for it. thanks all for the help! Would you guys say this truss rod is a replacement for the rod I have? http://www.stewmac.com/Materials_and_Supplies/Truss_Rods/Adjustable_Truss_Rods/Traditional_Truss_Rod_Kit.html Link to comment Share on other sites More sharing options...
Members FretFiend. Posted June 2, 2016 Members Share Posted June 2, 2016 Maybe... if your broken rod is 3/16 inch in diameter. Measure it. You still might need thread cutting tools, and another nut. You can get a piece of stainless steel rod of the correct size and a couple of stainless steel nuts of the correct size from any of hundreds of different online vendors for practically peanuts. The threading tools might be a little more expensive just for this one use. Again, any decent mechanic should have the threading equipment, and probably wouldn't charge much just to thread the ends of the rods. Link to comment Share on other sites More sharing options...
Members Freeman Keller Posted June 3, 2016 Members Share Posted June 3, 2016 Omar, you might be able to make it work but that probably not the best way. First, however, let me apologize for maybe leading you astray. I've been looking at your pictures and trying to fit them into the context of truss rods that I've seen, but I realize now that it is something quite different. A Gibson style rod is a simple threaded piece of 3/16 rod (like your StewMac link) but doesn't have the square tube. A Martin style rod has the square tube and a threaded rod inside, but it doesn't come out like yours did. Both the Gibson and Martin rods would have been really difficult to replace - both would have required removing the fretboard - but it looks like you can simply have a new rod made and thread it into the tube since you have the neck off. Stick the rod back in the neck and see where you think its broken off - 1/2 inch, 3/4 inch, it doesn't really matter - err on the long side since you can always cut it off. Take it to a machinist (a mechanic works on cars, a machinist works with metal) and ask her to make one just like it with the additional length. Get a nut and washer to fit. Put it all back in, add the nut and washer and tighten as required to adjust the relief. Put the neck back on the guitar, do whatever is necessary for neck angle, do the frets, set the relief and angle. Disregard everything I said above about replacing the truss rod, removing the fretboard, compression fretting... Report back Link to comment Share on other sites More sharing options...
Members Omar562 Posted June 3, 2016 Author Members Share Posted June 3, 2016 Just came from the hardware store. I found the exact same rod that I have to cut to length and then thread the tip, but I wouldn't have the end that anchors to the end of the neck by the sound hole.And the thread and tap set was pretty expensive haha. So what I did is buy the same size thread screw and ill just cut it off and weld it to the rod. It'll be perfect length as I only need 1/2 inch. It'll be the same rod, so ill just be adding thread to it. As for the nut, I couldn't find the open end acorn type nut that gibson uses. So ill have to order it for like $6 which isn't too bad. What do you guys think about using a regular nut? i don't know if I like that haha which is why I'm opting for the gibson truss rod screw http://www.ebay.com/itm/Truss-Rod-Nu...IAAOSwv9hW2-PL. I think it'll work out great. I could have made a new rod but a lot of mechanics in my area would not want to waste their time in making me a new rod. I think they'll dread it when I show them the rod and the wielding needed. it'll probably cost $10 just to add the threaded part to the rod from the screw. What do you guys think? Link to comment Share on other sites More sharing options...
Members Freeman Keller Posted June 3, 2016 Members Share Posted June 3, 2016 What I think you are saying is that you plan to extend the threaded end by welding on some more threaded rod. Your problems will be aligning and holding the pieces perfectly straight and aligning the threads - almost impossible in my humble opinion (my background is an retired engineer that worked in a machine and fabrication shop). When you talk about welding, are you going to do it yourself or have it done? If you take your pieces to a welder he/she will explain to you why it won't work. It might be possible to cut the head end of your carriage bolt off and weld it on to some threaded rod (commonly called "all thread") but again you will have alignment problems and you will have to turn the weld down to the diameter of the rod to get it to fit into the tube. The head of a carriage bolt has a little square area that is designed to fit into a square recess (in your case the tube) to keep it from turning as you tighten the nut. In your case the head end of your rod also needs to fit into the recess in the heel. The Gibson nut is brass which is less likely to rust to the rod and has a little bit longer threaded area. Make sure that whatever you use fits inside the routed pocket in the headstock. The large flat washer is important as the bearing surface for the rods compression against the neck - on some Gibson style rods it is a special shape to fit this route. Without seeing your parts it really is pretty hard to comment - taking it to a mechanic would be your best bet. Last comment, make sure your materials are compatible - its pretty hard to weld stainless to black iron - again your welder will know this. Link to comment Share on other sites More sharing options...
Members Omar562 Posted June 3, 2016 Author Members Share Posted June 3, 2016 hmm I se. what I was going to do is cut the broken threaded part of the rod and attach the threaded of the screw. but even then it will be hard to align so i see what you're saying. Ill take it to the mechanic and see what they say. thanks! Link to comment Share on other sites More sharing options...
Members guitarcapo Posted June 3, 2016 Members Share Posted June 3, 2016 Can't you force out the old rod from one end with a bolt and hammer and replace it with a new one without removing the fretboard? I'd attempt that. If the channel isn't forgiving I'd remove the fretboard. It probably could use new frets anyway Link to comment Share on other sites More sharing options...
Members FretFiend. Posted June 4, 2016 Members Share Posted June 4, 2016 Have you even bothered to look at the photos the OP posted??? No, you haven't. The neck is off and the rod is out of the neck. Fixing that one is a piece of cake... for anyone with half a brain. Link to comment Share on other sites More sharing options...
Members Omar562 Posted June 4, 2016 Author Members Share Posted June 4, 2016 Yup, easy fix for me now that I know how to fix it. Ill post pictures after I'm done with the rod and putting back the neck so you guys can see it Link to comment Share on other sites More sharing options...
Members Omar562 Posted June 4, 2016 Author Members Share Posted June 4, 2016 Yeah the rod just fell off when I took the neck off, the thing is no one sells this exact rod. So i have to make one or repair the broken threaded rod. i decided to fix the broken rod and ill just slip it back in and fasten it with a nut. Link to comment Share on other sites More sharing options...
Members Idunno Posted June 4, 2016 Members Share Posted June 4, 2016 I'd fix it with a match. Guess I'm not a somebody-elses-junk romantic. Seriously, what's the return on a vintage cheapo POS? It's not going to sound great, look great or ever be great in any other form. It wasn't when it was new. You won't get any return on the investment, either. If this is just a practice piece for repairman skill training then I'd consider it of some value. Otherwise, the logic isn't there. Link to comment Share on other sites More sharing options...
Members guitarcapo Posted June 6, 2016 Members Share Posted June 6, 2016 USA made Harmony jumbo's are actually the "best kept secret" of vintage acoustic guitars. They have a lot of features that are just plain impossible to purchase on a new premium acoustic guitar at any price. 1. The fingerboard and bridge are made from Brazilian rosewood. This premium hardwood is banned from import into the United States. 2. The neck and back and sides are solid "one-piece" Honduran mahogany. Not only is Honduran mahogany replaced with other substitutre mahogany species these days, it is often built up from multiple pieces. Even a Martin D18 (new or vintage) has a two-piece Honduran mahogany back. Old Harmony guitars are one-piece. 3. Old Harmony guitars have old growth American red spruce soundboards. Most modern acoustics (even premium American brands) use Sitka. 4. Old Harmony guitars are glued together with HIDE glue....not the inferior aliphatic resin glue used on modern expensive guitars. 5. Old Harmonys are finished in spirit shellac. Not the inferior polymer resin used on guitars like Taylor. Martin and Gibson use nitrocellulose laquer, which is better sonically...but less stable chemically. Which is why it yellows with age and cracks. 6. A 60's Marin D-18 will set you back over $2000 easily. But guess what? NO adjustable truss rod! Harmony acoustics have them. 7. What about celebrities who played them? Harmony acoustics were played by people like Pete Townshend and Jimmy Page back in the day. And arguably the most famous acoustic passage in rock and roll history was played on a jumbo Harmony Sovereign. Namely the intro to "Stairway to Heaven" All this for maybe $400 on Ebay (snap one up quick because the word is getting out) Link to comment Share on other sites More sharing options...
Members Omar562 Posted June 8, 2016 Author Members Share Posted June 8, 2016 haha yeah you're right. The wood on this guitar looks awesome. The fingerboard does look like brazilian, and the wood of the body looks really aged. I think its going to sound awesome when I put the neck back on. I only got it for $25 at a swap meet haha, even came with he original tuners but they're super weak so I'm replacing them with the open back grovers. I'm excited! Link to comment Share on other sites More sharing options...
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