SSS-tonelover Posted April 12, 2023 Report Share Posted April 12, 2023 Question: what is best way to get this neck working again? Note: You can consider this a cheap practice neck, I have plenty of good necks, but I want to improve my chops, that's all, and if I can get it working, even better! The bow is approximately 2mm+ deep at the max point and well centered on the neck. I can see that the previous luthier tried to tighten the truss rod but due to an overly deep channel on the neck even extreme overtightening could not straighten the bow, just strip the bolt.-One part of the solution is to drop in some wood strips to get the channel to the right depth-The main part I have trouble with is how to get the bow out. What I tried: A heat gun with clamp pushing the bow straight concurrently did not work -- or I was not aggressive enough, or have to push it beyond straight to get it to take a new set.... I'm thinking a completely different approach at this point may work better. Ideas and solutions to try? Quote Link to comment Share on other sites More sharing options...
mistermikev Posted April 13, 2023 Report Share Posted April 13, 2023 so I will answer you best telling a story... back in 95ish i lived in L.A. and walked into the carvin store over on sunset (the rock walk yeah!) and bought a carvin neck thru body blank. Idk if it had issues when I bought it (I was pretty inexperienced back then) but after building it and investing in it... I realized that at the 3rd fret it had an incredible back bow. I took it to a reputable luthier in L.A. that had a "steam box". He was sure he could fix it. Gave it to him for a week... and at the end of that week he gave it back to me and said "no charge"... it couldn't be fixed. For years I just set some heavier strings on that guitar and dealt with sub-optimal action. Years later I moved to AZ and had my own "steam box" - that's just what I call my garage when it is 120 degrees out. Like a sauna in there in the summer... dry but easily hits 130... maybe 135 when it's that hot. I had bound the neck to something perfectly flat, set that guitar in my garage over a heat spell for about a week. Then took it inside and let it acclimate for a day or two. Unbound it and it was now perfectly straight. put some strings on and it played like a dream w 1/16" action. That lasted about 3 weeks and on it's own it slowly returned to exactly where it had started. The moral of this story is: the wood wants what the wood wants. I am aware that people steam bend wood all the time... acoustic guitars for instance. I have steam bent it myself... but that is typically very thin wood. I think when you are dealing with something as thick as a neck... it is not possible to permanently bend it with precision w/o some other force holding it in place. with this neck... if I HAD to try to fix it... I would try to bind it to something straight and apply heat/steam to it to get it where it needs to be... then immediately glue in carbin fiber strips to fix the truss rod channel and reinforce, then glue the fretboard to it and bind it to something flat. the fretboard/carbon fiber MIGHT hold it in place. That said... it is well established that musicman bakes in a fwd bow to their guitars by glueing them to a radius. this is typically not done with dual action truss rods, but the sm principle will apply. It doesn't HAVE to be straight... but you might want to ensure it is a perfectly straight arc that you are setting into it. You can force it straight to do the fret leveling or use a 'katana' to get it leveled. just know going in... all of this is not GUARANTEED to work. You may put a lot of effort into this to find it is twisted and too resistant to straightening. You may find that after all this the wood is just fighting too much. at that point: "kill it before it grow". hope something there helps. Quote Link to comment Share on other sites More sharing options...
Bizman62 Posted April 13, 2023 Report Share Posted April 13, 2023 Another option might be to level it by removing material - planing or sanding - and then add a veneer to get back to the desired thickness, cutting the slot open. 1 Quote Link to comment Share on other sites More sharing options...
SSS-tonelover Posted April 13, 2023 Author Report Share Posted April 13, 2023 Bizman, As I was tossing and turning in bed (I get lazy about getting up sometimes!) I was thinking of that too. It would be pretty fast and reliable, not depending on heat technique. Don't get me wrong: I love heat for bending veneer, 'popping' dents out of bodies too, but I wonder if heat techniques could get it dead straight. I think it could get it close but whether that remaining amount was an under or over correction, I'd still need to do some flattening and as this is not some vintage pices I can easily live with a layer of sandwich veneer to build back the thickness. Quote Link to comment Share on other sites More sharing options...
SSS-tonelover Posted April 13, 2023 Author Report Share Posted April 13, 2023 Hi Captain Obvious, I love your two stories, cautions, and experience. I agree the depth of the wood and its intrinsic nature will make a 'heat fix' problematic over time so is best avoided. I have only invested ~$8 on a new truss rod, plus have plenty of veneer (poplar in 1/16" thickness, the others all 0.5mm) and plenty of sandpaper and a great sanding beam, so I will try a 'mechanical' solution, mindful too that I have to build up the truss rod slot so the rod can sit tight in its slot and have adjustability in both directions when all glued up. Yup time to level this neck shaft and then set up for next steps. If it looks a bit strange with a sandwich of veneer, no worries. 1 Quote Link to comment Share on other sites More sharing options...
Bizman62 Posted April 13, 2023 Report Share Posted April 13, 2023 15 minutes ago, SSS-tonelover said: If it looks a bit strange with a sandwich of veneer, no worries. Just a hint: You can make that sammich even more to a feature by using more than just one veneer. Figure a 0.5 mm stripe of something as dark as the fretboard and something closer to the neck over that... Another hint: When gluing the veneer(s) and the fretboard, clamp the neck straight or even to a very slight backbow. A length of 2x4 should provide enough resistance and some wedges or small blocks should support the middle part when clamping. Quote Link to comment Share on other sites More sharing options...
SSS-tonelover Posted April 13, 2023 Author Report Share Posted April 13, 2023 Yeah, I like features, and that looks like a good way to turn a problem into an artistic improvement as well as solving the issue. The other hints are good too. Thanks! Quote Link to comment Share on other sites More sharing options...
SSS-tonelover Posted April 13, 2023 Author Report Share Posted April 13, 2023 OK, first pass: Sanding maple is a bitch so within minutes I switched to my router and set it up as a router sled. Quick work with that setup. I only shaved based on the low spot, and took about 1.5mm off, so slightly less that my earlier calculation of 2mm. I then flipped the neck over and hit the high spot on the other side using the router sled again for that too. Rounding off the shaft will be by hand. As far as the veneer seeing that I needed about 1.5mm I elected 5to use the 1.5mm thick poplar I have big sheets of.... so I could know out that part of the glue up in one step instead of 3 (0.5mm x 3 to get the same build up). That veneer was clamped to my dead straight LMI sanding beam along with the neck. I'll let it set up overnight and then see how flat it is. I'm guessing within 0.5mm or less, but only time will tell. Yes, the method using a slight backbow like in the illustration Bizman62 showed. That could work well too I'm sure, maybe better. Ah, decision was taken, fingers crossed! 2 Quote Link to comment Share on other sites More sharing options...
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