Bernard d'Uur Posted March 23, 2006 Report Share Posted March 23, 2006 OK, here's the deal; I am restoring a beautiful old EKO hollowbody; it has one flaw: when I put pressure on the neck (as in by strings) the neck bends "into the body" thus giving the guitar a really high action. What is the usual way of correcting this? Quote Link to comment Share on other sites More sharing options...
unclej Posted March 23, 2006 Report Share Posted March 23, 2006 OK, here's the deal; I am restoring a beautiful old EKO hollowbody; it has one flaw: when I put pressure on the neck (as in by strings) the neck bends "into the body" thus giving the guitar a really high action. What is the usual way of correcting this? the method of correction depends entirely on the cause...and there are several possible causes. the block that the neck is set into inside the guitar may have come unglued..the dovetail joint inside of that block may have come unglued ..the truss rod, if it has one, may have broken or may simply need adjusting. so here's a question or two that may help you decide what's wrong.. does it have a truss rod? when you say high action how high is it at say the 10th or 12th fret? when you sight down the neck with no string tension does the neck appear straight? back bowed? front curved? now try this without string tension..put the guitar in your lap in playing position..brace it tightly against your body with your right arm and push and pull the neck with your left..holding it up around the headstock. do you feel it move where the neck meets the body? can you hear any cracking/scratching like noises? post your answers and perhaps one of us can narrow down your search. Quote Link to comment Share on other sites More sharing options...
Bernard d'Uur Posted March 23, 2006 Author Report Share Posted March 23, 2006 (edited) Yes, it has a truss rod; the neck is perfectly straight. When there is no tension on the strings, the action is good (approx. 3 or 4 mm), when the strings are tightened the neck "dives" into the body to get an action of about 3 cm..... not playable. And then the guitar is not in tune () When I take the guitar unstrung I can move the neck into the body by appying pressure on it. There are no sounds or noises hearable. When I look at the wood there it looks "weird" (I can put holes in it with my fingernail). There is no dovetail Hope it helps. Oh, btw, this is a pic of that area Edited March 23, 2006 by Bernard d'Uur Quote Link to comment Share on other sites More sharing options...
Southpa Posted March 23, 2006 Report Share Posted March 23, 2006 (edited) when I put pressure on the neck (as in by strings) the neck bends "into the body" thus giving the guitar a really high action. Hard to interpret exactly what you mean here. Does the neck actually bend or does it tilt at the neck joint area? As far as playability goes these guitars are no great shakes. As a matter of fact I will go as far as saying they can be a real POS! Here are some pics of my "Modello X-100" that I refinished a few years ago. http://img53.imageshack.us/img53/7762/eko33ir.jpg The laminated, bolt on neck is very thick and blocky. I don't even know why it has a truss rod, it takes an awful lot of pressure just to make a slight bow. The action is very high on mine and I decided to heighten at the zero fret for slide playing. I would check the anchoring of the screws that hold the neck to the body. When you tighten the neck down do the screws snug down well? Edited March 23, 2006 by Southpa Quote Link to comment Share on other sites More sharing options...
Bernard d'Uur Posted March 23, 2006 Author Report Share Posted March 23, 2006 It tilts; the neck remains straight. When the neck should be as it is without pressure the guitar would be quite playable Quote Link to comment Share on other sites More sharing options...
unclej Posted March 23, 2006 Report Share Posted March 23, 2006 ok, i didn't realize that it was a bolt on neck..i saw the pic yesterday and didn't respond but having the hole for the neck pup may help you troubleshoot it more. assuming that you have the screws sufficiently tightened try the bending it with your hand thing again and see if there's movement at the bottom of that block where the glue has sqeezed out. if not see if the block itself is compressing..i suspect that it is because of what you said about being able to mark it with your fingernail. if the block has rotted or become soft it will probably have to be replaced and i don't really know how much trouble that would be having never done it. it appears to be glued on the bottom and three sides so it could be a big pain to get it out. it just occured to me that the existing holes in the block for the screws might be wallowed out as well. do the screws just slide through or do you have to screw them to get them to make contact with the neck when it's in place? Quote Link to comment Share on other sites More sharing options...
fryovanni Posted March 23, 2006 Report Share Posted March 23, 2006 It tilts; the neck remains straight. When the neck should be as it is without pressure the guitar would be quite playable Have you tried lighter gauge strings? What you are describing sounds like either the body is collapsing under the tension. It will be a real challenge to reinforce it if damage is being done at the neck block and rim(especially if keeps moving-causing more damage). Look to see if the body is warping as tension is applied(top and back). Hopefully the problem is just too much tension applied by heavy strings, and lighter ones keep the tension low enough for the guitar. The soundboard was probably not braced for the pickup hole that was added, and that may have weakend the structure. If this is the case you may be able to re-inforce around that area ( maybe 3/16" tall by 1/4" wide spruce strips, glued under the soundboard around this area). Adding bracing will dampen the soundboard, but not as much as the pickup(which hopefully will be supported by something other than the soundboard, maybe an extension of the neck block.). Good luck with it, Rich BTW; I am not familiar with this guitar. I am just basing what I say on your picture and the other fellas picture of the same model. Take my advice for what it is worth. Quote Link to comment Share on other sites More sharing options...
Bernard d'Uur Posted March 24, 2006 Author Report Share Posted March 24, 2006 Nope, lighter gauge strings does not work (already have light gauge one on it). The body is not warping when pressure is applied to it; would I be able to replace the neck block? Quote Link to comment Share on other sites More sharing options...
fryovanni Posted March 24, 2006 Report Share Posted March 24, 2006 Nope, lighter gauge strings does not work (already have light gauge one on it). The body is not warping when pressure is applied to it; would I be able to replace the neck block? Do you think the neck block is rotten? Are the neck screws crushing into the block? Keep in mind the neck block and tail block are usually pretty solid. They are really anchors for the box. The box itself has to be braced well enough to hold its shape under the tension of the strings. Even if the neck block is solid as steel, the braced top/back and sides have to carry the tension without deformation. When you build a soundboard you want it to be as lightly braced as possible to capture that string energy, but strong enough to not collapse. If you have a box that is braced well and then remove a chunk of it you are weakening its structure(a structure that is made as light as possible, using all of it's mass for just enough strength). If you do decide to replace the neck block(assuming the wood is rotten). I would remove a section as cleanly as possible and replace it with good wood, but be sure to get a clean fit(extreamly close- bacause it is going to be difficult to clamp without deforming the joints and or cracking the heck out of the top, back and sides). Peace,Rich Quote Link to comment Share on other sites More sharing options...
Southpa Posted March 24, 2006 Report Share Posted March 24, 2006 Ok, you have to identify exactly what is moving out of position when the strings are tightened up. Look for cracks in the finish around the neck joint area. With the strings loose pull the neck into the direction that its going with string tension and see if you can identify what part of the body is moving with it. And you DO have a steel plate on the back of the guitar for bolting on the neck, right? Quote Link to comment Share on other sites More sharing options...
fryovanni Posted March 24, 2006 Report Share Posted March 24, 2006 Ok, you have to identify exactly what is moving out of position when the strings are tightened up. Look for cracks in the finish around the neck joint area. With the strings loose pull the neck into the direction that its going with string tension and see if you can identify what part of the body is moving with it. And you DO have a steel plate on the back of the guitar for bolting on the neck, right? Did you take a look at the pic that he posted of the neck joint area(where a good size chunk of the top has been cut away just below the neck for a pickup)? Might be some clues there. Peace,Rich Quote Link to comment Share on other sites More sharing options...
unclej Posted March 24, 2006 Report Share Posted March 24, 2006 i just took another closer look at the picture and unless i'm mistaken that's not glue that's seeped out..it looks like expanded foam..look right at the top where the skin has been removed from it and there are voids..air bubbles if you will...if it is it would seem to indicate that the neck block had come unglued and the neck was moving and someone shot the expanded foam into the gaps.. take a sharp knife and see if you can easily cut the part that oozed out..if you can then that's probably what it is..if it is indeed expanded foam i don't see any way to fix it other than carefully cutting/chiseling out the entire block and all that foam and starting over with a clean surface and then replacing the entire block.. Quote Link to comment Share on other sites More sharing options...
fryovanni Posted March 24, 2006 Report Share Posted March 24, 2006 Ok, this one is really bugging me. I would just hate to think about replacing that neck block. I have looked up a few pics of these guitars. Some with single pickups and some without. I have also studied that pic of yours. The bar that has a bit of red paint on it just below the neck block. I assume is a main bracing bar. Is it firmly in place? I see the small bar below it that has the big glob of glue on it and woder if that was placed to firm the main brace up. I also see what appears to be two cut bars that are on either side of where a smaller pickup may have been placed. Is that the case? If so can you feel any other bracing bars under the soundboard behind the pickup hole? Is there any seperation occuring between the beck and sides in the neck block area? If the neck block has broke loose from the back allowing for the neck to rise you would definately see that movement from the side of the guitar when the neck is pulled up(as though string were pulling). I would also think you would see a fair it of cracking in the finish behind the neck if that was the case. All that said though you still have the neck plate and neck screws that would really limit the effects even if this was the case. All I can say is I sure hope for your sake it is a bracing related issue(potential fixes would be much less difficult) Peace,Rich Quote Link to comment Share on other sites More sharing options...
Bernard d'Uur Posted March 24, 2006 Author Report Share Posted March 24, 2006 OK, I made some pics.... maybe it helps a bit as I don't understand fully what you are saying First two pics: no tension on the neck / body; action is good First pic (flash) same pic (without flash) Now I apply some tension (some tension; strings are still flapping around) Body enters body; action is high Then I searched around a bit and this suddenly dared upon me: crack Too much space on the sides Quote Link to comment Share on other sites More sharing options...
unclej Posted March 24, 2006 Report Share Posted March 24, 2006 your new pics confirm..to me at least..that there is movement of the neck block. i've got an old hollow body base in the shop right now with the same problem. in my case the glue between the bottom of the block and the back of the guitar had broken loose and it was fairly easy to force enough glue back into it to stableize it. in your case i'm still afraid that someone has forced expanded foam..used for insulating around windows and plug boxes..into the voids. if that's true you'll never be able to get glue back into the joints and solidify it again. did you ever try to cut that stuff and see if i was right about it not being glue? the only possible easy fix that i can think of is dependent on whether that cross brace in front of the block is solidly attached to the guitar. you might..and i stress might..be able to drill a couple of pilot holes trough that brace and into the block and then put a couple of wood screws in. that would minimize the neck movement but it might not eliminate it completely. that also depends on whether or not the block is still sound and not soft. Quote Link to comment Share on other sites More sharing options...
Bernard d'Uur Posted March 24, 2006 Author Report Share Posted March 24, 2006 Thanks man! I don't know if the foam is glue or not; it is really hard to get rid of and that can only be done with some heat....... I will try the screws. Maybe it works. Quote Link to comment Share on other sites More sharing options...
fryovanni Posted March 24, 2006 Report Share Posted March 24, 2006 your new pics confirm..to me at least..that there is movement of the neck block. i've got an old hollow body base in the shop right now with the same problem. in my case the glue between the bottom of the block and the back of the guitar had broken loose and it was fairly easy to force enough glue back into it to stableize it. in your case i'm still afraid that someone has forced expanded foam..used for insulating around windows and plug boxes..into the voids. if that's true you'll never be able to get glue back into the joints and solidify it again. did you ever try to cut that stuff and see if i was right about it not being glue? the only possible easy fix that i can think of is dependent on whether that cross brace in front of the block is solidly attached to the guitar. you might..and i stress might..be able to drill a couple of pilot holes trough that brace and into the block and then put a couple of wood screws in. that would minimize the neck movement but it might not eliminate it completely. that also depends on whether or not the block is still sound and not soft. Hey, are you thinking the foam is forcing the front of the block up and compressing under tension? The neck is bolted twards the back. With that plate and the neck sandwiching the body you won't get much movement unless the back and sides seperate( and I think that would be very obvious at the rear binding). I see the top is deforming like crazy. That tells me the body structure itself is failing. I see they cut in a second pickup also. I say a couple examples of EKO's with one small single coil at the neck position, but none appeared to have a second in the bridge position(I am assuming not factory). The combination of two pickups and all that material removed must be playing a role here. I think it is wise to check for expanding foam(god who would do that?? ). Confirm the neck block is seating. Get a small telescoping mirror and get a good look inside the body. Look for kerfed lining around the body that is seperating from the top/side or back/side. Look at the top and back bracing structures. See if you notice any seperation occuring. Also look very closely at the areas that have been cut. If you see these areas have had bracing cut and removed it is very improtant. Try to sketch a pic of the front and back bracing (note relative positions of holes). See if you can upload the sketches. Peace,Rich Quote Link to comment Share on other sites More sharing options...
Bernard d'Uur Posted March 24, 2006 Author Report Share Posted March 24, 2006 This EKO guitar has two pickups; originally they were single coils, but they replaced them with humbuckers. And yes, they screwed them into the wood (bit so were the single coils btw) so it is quite normal. This is a normal version.... And another one; more my color. Will check the rest later Quote Link to comment Share on other sites More sharing options...
unclej Posted March 24, 2006 Report Share Posted March 24, 2006 fryovanni..that's exactly what i'm thinking but i know that it's more complicated than that. i don't know about his guitar but this bass that i'm fixing doesn't have any interior bracing at all..none...it doesn't even have any kerfed lining around the perimeter. it has a sound post between the bridge pup and the bridge and then the neck block. i'm assuming that the structural integrety depends on the block and the stiffness of the sides where it joins the body. i'd almost be willing to bet that his guitar doesn't have any bracing either and if that's the case then the movement has to be caused by the movement of the block.. as you can see in the picture of the bass (link below) this one doesn't even have the front brace that his seems to have and in my case the joint around the top and back inside the horns and again on top of the block has failed and that was all that was keeping the neck from moving. it's really hard to really analyze Bernard's axe without being able to see it in person but i'd still be willing to bet that that's expanded foam and if it is there were a bunch of glue failures and that foam didn't do anything but fill the voids. if the screws through the front brace into the block don't help then it's either remove the block, which would be a total pain, or make a really cool lamp out of it. http://img.villagephotos.com/p/2004-10/867653/bass1.JPG Quote Link to comment Share on other sites More sharing options...
fryovanni Posted March 24, 2006 Report Share Posted March 24, 2006 fryovanni..that's exactly what i'm thinking but i know that it's more complicated than that. i don't know about his guitar but this bass that i'm fixing doesn't have any interior bracing at all..none...it doesn't even have any kerfed lining around the perimeter. it has a sound post between the bridge pup and the bridge and then the neck block. i'm assuming that the structural integrety depends on the block and the stiffness of the sides where it joins the body. i'd almost be willing to bet that his guitar doesn't have any bracing either and if that's the case then the movement has to be caused by the movement of the block.. as you can see in the picture of the bass (link below) this one doesn't even have the front brace that his seems to have and in my case the joint around the top and back inside the horns and again on top of the block has failed and that was all that was keeping the neck from moving. it's really hard to really analyze Bernard's axe without being able to see it in person but i'd still be willing to bet that that's expanded foam and if it is there were a bunch of glue failures and that foam didn't do anything but fill the voids. if the screws through the front brace into the block don't help then it's either remove the block, which would be a total pain, or make a really cool lamp out of it. http://img.villagephotos.com/p/2004-10/867653/bass1.JPG Hmmm... I guess Iam at a real dis-disadvantage not being familiar with these. I think you got the info and something to reference. I hope this works out. Sounds like the support system for this box is pretty slight. Anyway good luck with it fellas. I have to leave town (family emergency), so I won'tbe around for a bit. Peace,Rich Quote Link to comment Share on other sites More sharing options...
Bernard d'Uur Posted March 24, 2006 Author Report Share Posted March 24, 2006 Thanks man! Quote Link to comment Share on other sites More sharing options...
Southpa Posted March 24, 2006 Report Share Posted March 24, 2006 (edited) Well, we all know that a good fix only comes after a proper assessment of the problem. With the neck off the guitar insert a large long screw into one of the holes in the neck block and apply some force. At least you will be able to see exactly what is moving. From there you can decide whether or not the guitar is "fixable". It might be a simple matter of digging out all the old crap, injecting glue and clamping. Worst case scenario is tearing the whole top off and repairing or replacing bracing, block etc. If that is the case then its up to you whether or not the guitar is worth the effort/expense. Edited March 24, 2006 by Southpa Quote Link to comment Share on other sites More sharing options...
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