How to check for neck warp.

there are various types of "warp":

sighting down the neck from the headstock end makes it pretty easy to see twists, as the frets can be visually "stacked up" making that problem very apparent. a mild twist may not affect playability, but it's a warning sign that trying to adjust the truss rod may cause further twisting.

for bowing (relief) issues, the neck must be set up properly to be sure is it adjustable for relief in the critical areas -- usually nut down through somewhere in the 12 through 15 fret depending upon type and design of guitar. on newer models and electrics, the truss rod acts over a wider range. at the higher frets, if the there is more than a very slight bump or a dip in the fretboard (use a straightedge and/or strings pressed to frets), that is usually a problem requiring repair or neck replacement, as the truss rod doesn't usually affect curvature in the highest (and strongest) part of the neck. on acoustics, it is normal for the fingerboard to drop away slightly toward the fingerboard. that prevents buzzing on the high frets.

two more reasons to check with the relief (truss rod) properly adjusted: to make sure the truss rod is not broken. this may not be noticed immediately on maple and thicker necks. to make sure that adjusting the the truss rod within its normal range does not cause the neck to twist.

Thanks Grease-

I'll be having a good look at it...

I don't suppose you have an opinion on how hard it is to replace a bolt on neck, if necessary?

Best,
Ande

if the guitar has direct replacement neck available to match the neck pocket size/shape, placement on body (so scale is preserved), then it requires a working knowledge of measurement, good electric drill technique (and preferably a drill press) and sometimes woodworking skills, as nothing fits perfectly. don't forget you may need to put a finish on the neck.

Thanks again, man.

I've done some neck adjustments and shims, and quite a bit of carpentry, but am thinking I'll be taking a miss on this one if it's warped.

(It's a Peavey T-60, 28 years old. As far as I know, there isn't a ready to go replacement available.)

Best,
Ande

I've got a related question. I hope you don't mind me barging in on the thread.

If the truss-rod is broken, does that have any effect on twisting? (I know it obviously does on bowing)

probably not. an overly tightened truss rod -- or a crappy neck/truss rod design -- can result in twisting. but a single-rod truss rod design does not usually fix or inhibit twisting. A dual-rod truss rod design can inhibit and fix twisting. that design incorporates two, independently adjustable rods. (this completely different from a two-way adjustable truss rod design, which will provide both positive and negative relief correction.) dual-rod truss rods usually are found on 12 string guitars.

graphite (and once upon a time, ebony) reinforcing bars are built into some necks to help resist twisting. Stew-Mac sells them.

Thanks gnease. Just wondering if what I'm seeing on this old maple neck is no truss tension or actually twist.

I read your "strat murderer" thread. :D So I think I know how this got broken.

I've only broken one truss rod so far, under similar circumstances. I don't think the broken rod would CAUSE the twisting, but I can see how you might twist the neck when you were breaking the rod. (I've still got that broken neck somewhere- it's really twisted now.)

Or maybe the neck was already twisted, and that's why I couldn't get the relief right, and kept cranking until KA CHUNK.

Best,
Ande

Or maybe the neck was already twisted, and that's why I couldn't get the relief right, and kept cranking until KA CHUNK.

I'm thinking this was the case. Regardless, I'm sitting fat and happy with a rosewood fret board now. 8)