Hey, it's a long read, but help me if you can...Ugh. This sucks. I've ordered four ovangkol neck blanks from Gilmer over the last six months. Had them built into 1 piece Jazz bass necks by USA custom. Three fretless, one fretted. The Fretless with Ebony is fine... It's been on for three months, and is straight and stable. Sound is stellar.Though it's rod may have only a little tension on it, it set up great and plays great. A blackwood fretless board with the same ovangkol neck (appears) to be turning out OK, because I can induce forward bow with adjustment-even though it's not strung up...I'm still applying finish.I am encouraged that it will bow forward without strings on it. I have the highest hopes for the sound of this combo... The two problematic ones are a bit scary. A *gorgeous* sounding Pau Ferro fretless board on ovangkol has a totally slack rod, and bowed back pretty bad...after a third leveling, it is ALMOST ok. With Super light TI jazz rounds ( .89 -.43 gauge ,like rubber bands), it actually sounds great with only a few buzzy spots. Immense bottom end and midrange growl, clarity... It may turn out fine, but if it backbows more...disaster. One might say -"Just use regular 45-105 strings to induce forward bow...but i'm a TOTAL Thomastik fan, and have grown completely attached to both the the TI Jazz flats-very slack, and the TI jazz rounds- almost like no tension at all. They're both loud and incredibly musical. To me, after getting used to TIs, they simply ruin you for other strings, as they are so easy to play and incredibly nuanced. They make regular strings and gauges seem like clumsy cables with lots of wasted effort to produce clunky sound. I really mean that. And i've loved & played so many brands over the decades. The freedom of expressiveness on such light, yet lively strings as these is incredible, once one gets used to them. No lack of power. Just a tiny flick and the kick and growl. Lastly, and WORST, there's that FRETTED ovangkol neck with a wenge board. It's really back -bowed, when testing with a true straight edge and a fret rocker, all over the lower to mid-positions, and I wonder/doubt whether any amount of fret leveling can correct the backbow on the top side...again, the rod is TOTALLY slack. No more adjustment to be made. I told my tech I wanted to try leveling down to the super-low Jeff Berlin-type of fret height, but he says my 6150s will be too square at the base and will just feel awful...I have to question this...seems I've seen very fat frets leveled almost flat that felt great in the past. But all would be rendered moot if said leveling didn't correct this freaking backbow...geez, can you tell I'm mad? Being from USA CUSTOM, they are single -acting truss rods, and they won't to double-acting (I dislike the extra 4 oz weight and effect on tone/ wood vibration anyway). I understand why some manufacturers/ techs like double-action rods, but am firmly in the camp of many who just feel the metal dominates the sound, and really changes the wood's resonance. Plus the weight...my arch enemy. All moot regarding any solutions on these necks, anyway. I am at a loss as to whom to approach; USA may say the wood does what it does; it's not their supply. Although I'd WISH they had some useable insights! As to Gilmer; I imagine they'd refund me the truly minor cost of the blanks...but I still lose the extra 600.00 -plus bucks invested in each neck. I can hardly imagine heat treatments *really permanently* correct the bending of such a stiff wood as ovangkol, and so many people DIY crazy things, and I KNOW they don't operate with extremely close tolerances as the setups I use...30 -45 thousandths clearance at the 12th position. If they just want vague "playability," well, maybe. The whole purpose of my last six builds is ultimate sound, playability and STABILITY. So-so is just firewood to me. I will be consulting the very best luthiers I can find here in Colorado: but as always, the real qestion is Does Anybody Here KNOW (not guess) about wht can or can't be done to relevel the fingerboard to correct backbow, or heat treat & clamp a neck, *IF* a permanent reshaping is even possible? LIke, have you seen it, done it? This is a seriously cosytly and heartbreaking problem, affecting at least two, maybe three of these otherwise superb necks. I sure would appreciate any informed opinions, as I go to other luthiers. I Understand that taking off fingerboard material on a fretless can obviously correct the effect of the backbow, leaving a perfect playing surface, and that if the back bow does not continue, it would be fine. IF, THAT IS... I understand a single-acting vintage style rod won't correct back bow. (And that there's no chance of changing the rod type ) I did NOT like double acting rods anyway, and many others concur. Great adjustability, different vibratory properties. I know wood, especially super strong wood like Ovangkol, can do whatever the hell it wants to do. I have however, NEVER encountered this backbow before...I son't know what a manufacturer like USA Custom does with a neck blank (like quartersawn one piece ovangkol); whether they should somehow cut it differently than, say maple, to counteract the possibility of backbow, or if the trussrod should have been laid in differently...It's REAL hard to get detailed, cogent answers, just quick ones. I am surprised if GILMER, respected as they are, sent me two to four ovangkol blanks that are so nicely quartersawn, yet are warping like this...my personal contact at Gilmer assured me this is very well aged and tended- to wood. Again, I doubt they'd fuss too much about a refund. but each neck now represents about a 600.00 investment, after plainboard design with totally custom top lines ...oh crap, the effort that went into these otherwise perfect necks. None of them even weigh that much & the sound of each pairing is stellar. I am a little surprised that USA would build any backbow into the neck, as if it were maple, because Ovangkol is SO much stronger...unless their fingerboard fallaway is just that...such a thing is easily correctable by re-levelling. Lastly, I am peeved and bewildered that own my tech(after constructing SO many builds, first told me that removing fingerboard material at the apex of the backbow would be a VERY simple fix, then reversed his statement after the third relevel, saying "All I can do is level the board...taking material off to compensate for backbow doesn't work)...really? It's a TOTAL reversal of what he originally assured me was a piece of cake. I would assume with enough fingerboard, planing off the board would correct and perfect a stable piece of ovangkol beneath, again, ughh, so long as it does not continue pulling backward. If you've read this far, thanks...now, any helpful suggestions, or is there a viable fix? I especially worry for the fretted neck. although I do in fact want the Jeff Berlin "Fretless Wonder" super low frets on this one, with a hump at about fret 6-12, this may be impossible. It may be a write-off unless there's a way to reshape the neck itself, or pull the frets and shave the board, then refret. Oh joy. That would really be a waste and a gamble. I guess I can't believe that three respected parties in this process have to be addressed seperately, and each may just shrug it off. I 'd like some other input from people with REAL WORLD experience her before I call them. Can you help with ideas? MUCH APPRECIATED!