I'm writting this because there's next to no info about this stuff online and it might help someone. I just got a Harmony H22 project bass, just the neck, body, and three screws that hold them together. Upon arrival the neck had a bad backbow, truss rod adjusting nut that wouldn't move, and what appeared to be a counterclockwise twist when viewed from the peghead end. Some carving with a small screwdriver in the truss rod nut channel made it so a 1/4" box end wrench would fit. Before moving on to the neck I took some measurements with the neck relaxed (truss rod nut removed). E-side: (all measurements are approximate) Straightedge would rock on the 6th fret With 0" clearance at 1 and 6, there was about .076" at 20 With 0" clearance at 20 and 6, there was about .048" at 1 G-side: Straightedge would rock on frets 7 and 11 0" clearance at 1 and 7, .051" at 20 0" clearance at 20 and 11, .071" at 1 Before jigging I was under the impression that the G-side was backbowed more than the E-side as a result of the neck twisting. I got an idea - to set it up with a significant bow, but to only heat the G-side. I figured (hoped) that after it cooled and the clamp was removed that the E-side would stay about the same since it wasn't heated, and the G-des would straighten out some removing some of the twist. It was jigged up with an .080" bow on the G-side (couldn't measure E-side, clamp was in the way) and two 250W reflector infrared lights pointed at the G-side. After about 3 hours I figured that this wasn't such a good idea. That's one good thing about the heat lamps - they give you plenty of time to think and regroup. I thought it would be safer to try to correct the backbow first, and then deal with the twist. Otherwise it could easily get worse. I put one light on each side, and later on tightened the clamp for a .100" bow and left it that way for several hours. The clamp was removed many hours after it cooled. Using the straightedge it looked like the G-side was almost straight and that the E-side had a ski jump around the 11th or 12th fret. At this point I had a revelation and concluded that my original diagnosis was wrong - now it was looking like instead of the G-side being backbowed more and twisting down, the G-side was closer to normal and the E-side was twisted high (because of the ski jump). I was glad I rearranged the lights. Round 2. It was jigged with a backbow, clearance was 0" at 20 and 9, .085" at 1. One light on the E-side, no light on G-side. After a couple of hours I thought this was bad because the straightedge was only rocking on 1 fret and it might end up adding a backbow to the ski jump and make a mess. The clamp was loosened so the neck was more arched (straightedge rolled across two or three frets instead of rocking on one) and the clearance was about .025-.030". I left it like that and tried to imagine how it would turn out after cooling and how to jig it next. I was surprised to find it in what might be playable condition. It looks very out of whack overall, but the straightedge shows it being pretty good as far as the individual strings. I don't know what's going to happen once there's string tension, or how it will react to truss rod adjustments - it might want to kink sideways, it might act nice. If you're in a chair and set the heel on the floor it looks like the nut end of the fretboard is twisted a little counterclockwise (as before) and the headstock is twisted clockwise. Strange. It needs the holes for the tuning keys doweled and re-drilled. I'll borrow some TI flats from another bass and try them on this since they're low tension. I have a feeling that stiff strings might might be a good idea on this one.