Im in the middle of resetting this epiphone texan, and when I tried to take a read of the neck by putting light gauge strings on the neck is extremely bowed. looks like the tongue of the instrument is way high, but with strings off I can get the neck to back bow. truss rod seems fine. and with a straight edge it comes to just a hair over the top of the bridge. when string tension is on it looks like the neck pulls so far forward that the tongue might snap off, but the neck joint "finish etc" seems tight. Something is not right. could the truss rod not be solid? When i did bring the guitar up to tune, with a backbowed, tight truss rod. I heard and felt a snap or pop. but I thought it might have been one of the strings not fully seated against the bridge plate. and the neck was cocked forward immenseliy. Anyone ever deal with one of these?? I plan on refretting and resetting the guitar. but something else is definitely up..
When you say the truss rod seems fine , does that mean it works? Does it have any authority over the neck when it is stringed and badly up-bowed. Can you tighten up the truss rod nut ie: does it get tighter the more you rotate it clockwize in a proportional way. What is the relief at the 12th fret when it is at concert pitch?
Without any more information I would be looking at the truss rod or, considering it went bang while you were bringing it up to pitch maybe an internal top brace let go and the top has sunk in. Put a straight edge across the top in a longitudinal direction with the guitar strung to pitch and check that the top is OK.
Sorry to ask these suck eggs questions but we have to start somewhere. I haven't worked on this model so anybody who has will know more than I, but we'll get the ball rolling anyway.
the truss rod adjustment does very little when strung up to concert pitch. but works while not under tension. Id say the relief at the 12 was close to 1/8". the tongue is currently loose as well. as far as the braces and top go, they all look fine. No loose braces. the top has a very normal slight belly. I'm starting to think the issue is with the truss rod. but I don't know why it would work. I'm thinking I should proceed with taking the neck off and see if I can find anything out of the ordinary. possibly a cracked dovetail?
"when string tension is on it looks like the neck pulls so far forward that the tongue might snap off," - if the truss rod cannot bring back the neck to a proper relief and all bracing/top/back is sound then it is unlikely that a cracked dovetail (which would show up in finish separation or crack(s) in the heel area, it's likely to be a truss rod problem.
That the truss rod works when not under string tension is unusual if the rod is snapped but if the truss rod anchor is slipping or the wood around the anchor is gone or compressing that would do it. Also if the tongue is "loose" it may well be that the fingerboard over the rod end may be separating under the various tensions (string, truss rod etc) and causing some sort of bother. It's hard to say just talking about it.
Pete Townshend of The Who defined the art of luthiery in his song "Listening to you" when he penned:
"See me, feel me, touch me, heal me"......... which pretty much sums it up.
If the tongue is completely lose, you can loose a lot of neck support making a hing point out of the neck body joint.
Now you're saying the neck is bowed but you also say the movement is enough that the extension might snap off and that the extension is loose. Usually the truss rod doesn't have a lot to do with controlling movement at the neck joint in a guitar of this vintage since the rod probably ends at the heel. If the "bow" is at the neck/body junction you definitely have something going in the upper body area such as a loose brace, loose neck block, cracked top loose joint... Something to look at besides the bracing in the top of the body is the neck block. If it's loose you will get some odd movement. The kind of movement you;re seem to be describing sounds like it should create a gap in the neck joint at the base of the heel. If it doesn't check the angle of the neck block strung and unstrung to see if it's moving. I'm assuming that there are no cracks in top next to the fingerboard and that there isn't any sort of deformation in the area where the sides meet the neck.
As Rusty already said, it's hard to tell much without the "Peter Townsend" type connection. Pictures would help some particularly if you can get some with tension and without.
BTW, are you able to move the neck around any by hand?
Ok I got bit of steam in this baby. and the neck won't budge. the cheeks of the neck seem to be crazily glued to the sides. I tried getting a palate knife in their but would barely budge. Steam is also pouring out of the sound hole which isn't good either. Could this have some crazy neck joint Im not aware of?
I think the fingerboard needs to come off. I think this is what I'm looking at.
Frets.net to the rescue once again - don'tcha just love this place. Rusty.