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Hello all, new here and on a mission to get a bit educated on repairing my own guitars. I have a 1971 Cortez, it is a Gibson L6S copy, seems to be of very good quality and was made in Japan. I wanted to inspect the truss rod for damage and makse sure it was in tact, so I removed it { without removing the fretboard!! } and this small metal shim fell out of the truss rod shaft. Measures about 3/8" long X 1/8" wide. I believe it may have sat somewhere on top of the truss rod but can't be certain. Anyway, not knowing what is was and where it went, I taped it to the top of the truss rod way down by the end of it near the neck joint, figuring it acted as some kind of "stop" piece to keep the truss rod from potentially spinning or turning. Now that I have everything back together, I'm second guessing myself and would like to find out just what it is and where it's supposed to sit before I move on to my electronics part of my repairs. Any ideas??

Too bad you didn't take any pics before you put it back together.
I am not familiar with Cortez assembly practices...

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lol I got pics of everything but that metal shim thing! Wondering if I should leave it be or take the rod back out and figure out exactly it's purpose and location. This is a bolt on neck with no way to remove the truss rod EXCEPT for removing the fretboard OR drilling a hole in the end of the neck slightly larger than the end of the rod, slide it out, inspect, and slide back in and replace hole with wood dowel and glue I drilled a hole in the end and seemed to work quite wel

Did the shim look like it had a little whole, weld or other mark right in the middle? Have you tried tightening the truss rod yet to see if it works? The only thing I can think of is the "shim" is the truss rod anchor, and if it is the truss rod is now spinning in the neck with no way to tighten it. it's just a steel rod, right? Not a double action truss rod? If the anchor isn't broken, I'm having trouble imagining how the rod came out at all.

Pictures or much better description is necessary, but I have a feeling that truss rod is busted. That said, this is the first time I've ever heard of removing a truss rod for a non repair reason. We check truss rods by tightening them and seeing if they make the neck move. I don't think I would ever remove a working truss rod...ever.

That was my thought as well, even a 2-way rod will not allow the rod to be threaded back out and I can't see pulling one out through the adjustment access. But I see a hole was drilled to remove the rod from the heel end of the neck so pics of the rod will help. It could simply be the half moon washer used under the adjustment nut ala Gibson.



Definitely +1, and welcome to the forum.

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Brian

You never know what you are capable of until you actually try.

https://www.howardguitarsdelaware.com/

I removed the truss rod via drilling a hole at the heel. I marked the exact center of the rod and transfered that to the heel as a starting point. Removed the adjustment nut at the other end and pushed the rod right out the heel end. It does in fact have an anchor at the end and everything looks to be in tact. I know, I should not have done that, I guess i was in expiriment/learning mode. I then slid the rod almost all the way back in from the heel end. I peeked inside the nut cavity and that is when I noticed this rectangular metal piece. It was sitting on top of the metal truss rod channel at the very end, so I'm thinking when I pushed the rod back in maybe I pushed that metal tab up toward the nut cavity.It does not show any signs of being soldered or welded to anything. Anyway, yes I tested the adjustment and it did make a slight backbow in the neck as I turned the nut clockwise. Turn back counterclockwise and the neck was dead on straight, but at that point, the adjustment nut is pretty much in a loose position, or just snug enough on the threads to stay put, so the neck cannot be adjusted in the other direction I guess. Not sure if that is normal or not. Anyway I cut a dowel and glued back into the hole I drilled so I do not have pics of that metal piece.

That's pretty normal. Most necks comes straight with the truss rod loose unless the builder intentionally put some relief in the neck. It will pull into relief when you put string on it. FWIW, the test I always give a guitar is I tune to pitch, and loosen the truss rod. I need to see at least .010" or .015" of relief to make me happy. Then I try to flatten the neck with the truss rod. Ideally, I'd like to be able to back bow it, but if I can get it flat, I'm happy. I measure the wood with a notched straight edge. I don't care what the frets are doing...I can fix those later. That's my test. If it fails either one, I need to think long and hard about where we're going with the guitar.

For example, if it's an acoustic and I can only get it straight to .005" relief, I may not mind that so much, especially if the customer is just a strummer. Also, that's something I can easily fix with the next fret job. If an electric only pulls into .005" relief, that's probably fine too, depending on the player.

Well I got it all back together, it sounds very nice with the bone nut I made for it the other day. I just wish I had the experience to make sure the string heights / pickup heights and bridge height are where they are supposed to be. I'm not too confident in the grroves I cut into the new bone nut. I didn't cut them deep but not sure how precise I need to be with those slots.

Where do you live in CT? I'm right outside of Hartford. If you're in the area and would like to stop by the shop, you're more than welcome. We can have a look at it.

I'm in bethlehem and that would be great if I could stop by!

Ok, this little metal piece was bugging me so I took the rod back out and have attached some pics. It was initially somewhere inside the metal truss rod channel, as in the picture looking down the nut cavity. The rod is not broken so I don't know why the adjustment nut has very little travel and is hard to turn any further than say a half a turn from the snug point. Anyway, attached pic of the metal plate/shim, the end of the truss rod and also a pic of looking down at the rod cavity where the piece initially fell out. Could have been anywhere from that point and all the wya down to the heel...

Now what did we tell you about fiddling with a perfectly good trussrod? LOL.

Seriously, I haven't got the foggiest idea what that could possibly be. Looks like a key of some kind. I'm surprised it even fits in the channel, to be honest. The truss rod should be fit pretty tightly. I can't imagine it's so loose that a hunk of metal can just casually be slipped in there. I would be tempted to just leave it out rather than risk haven't it rattle around in there, unless you can really figure out what the purpose it. That's just my opinion.

re: running out of adjustment.
You might be bottoming out on threads. It's very common for the wood under the truss rod washer to be compressed over the years. It's also common for the wood around the anchor to compress. There's a number of ways to fix that, though most people start by adding a couple of additional washers. A slightly better fix is to make a hardwood shim (something HARD, like rosewood...ebony...cocobolo...etc) and glue it in there. It's sort of like a permanent washer.

Ah...I just noticed this is not just a rod. That changes things a bit. Hmmmmm.....

Note to self: when curious about innards of vintage guitar, go outside and find fallen dead tree branch and begin whittling.

I don't know...I'm stumped. I also don't know why you're running out of thread, if that's what's happening, because obviously the metal isn't going to compress. Maybe the bit of metal is a little shim that went between the anchor and the metal u-channel? That would essentially expose more thread and allow you to tighten the rod more. I just don't know.

My guess is that the piece is supposed to be in between the rod and fretboard, half-way up the neck.
This would induce a bow in the rod, and put the tensioning force where it will allow better adjustment.
Just a thought...
Coe Franklin

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Check my oil too, if you don`t mind,,,

Looks like a Martin style single action. LMI makes mention of plastic spacers to keep the rod centered in the channel and prevent rattles, maybe this one had steel spacers? here is LMI's description

http://www.lmii.com/carttwo/thirdproduc ... +Truss+Rod

Also here is a pic I found of inside of one, notice the spacers. I think it's going to buzz now, don't know how to get things back in correct positions without removing the FB and pulling the rod.

_________________
Brian

You never know what you are capable of until you actually try.

https://www.howardguitarsdelaware.com/

that Martin style is exactly what I have in there, even had that plastic glue guard thing that sits on top of the U channel come out in a balled up mess. As far as having enough thread, there seems to be plenty. I temporarily put the rod in last night so it sat tight and only a 1/4" of thread was protruding past the square washer, so there's plenty of thread behind it. Back to the metal shim- well, it only fits in that U channel one way { lengthwise } so it either sat on top of the truss rod in the center like mentioned above or on the side to prevent buzz, but if that were the case, why just one???

These picture I found on the web of someone else's guitar with the same Martin style rod and u channel. When I re-install mine permanantly, should the anchor end { flattened end } sit away from the end of the u channel or should it sit tight against the end of the u channel? I'm thinking it should sit tight against the end of the u channel. As far as the metal spacer goes, should I decide to put it back in, I can wrap a piece of scotch tape around it against the rod then slide it back in.

Ahhhhh, it's all coming back to me and now I remember how I got into this mess in the first place - I removed the truss nut all the way out and the threaded end slid back too far beyond the point of extraction. That tells me that there was a space or cavity in the heel end in the first place before I even drilled it.