Shouldn't the truss rod make the neck perfectly straight?

[lefty007]

I have had something like 30 basses in the last 10 years, and I think that by now I have some knowledge of setups and truss rods. . .

I like to setup my basses with perfectly straight or nearly straight necks, with just minimal relief.

But I have noticed that some basses just won't get perfectly straight, even when maxxing out the truss rod (carefully, I know. . . I know when to stop turning).

Obvious examples are vintage Fender, that due to mishandling, or whatever, won't get straight unless you use super light strings or take to a repairperson to clamp the neck and help it get straight, etc.

But surprisingly, I have encountered some modern basses, like most American Fenders (P-Basses and Jazz Deluxe) that when using the stock strings (.110) can not achieve a straight neck. (They get almost straight, and play nicely, but they still show a slight forward bow. If I use lighter strings, the neck indeed gets perfectly straight.)

Is it supposed to be this way? Meaning, why a manufacturer will not design the neck to be perfectly straight with the string type and gauge they ship them with?

Also, I have had two Sadowskys, and even with light strings, the truss rod maxxed out before reaching a truly straight neck. . .

Any thoughts?

Thanks.

[seanm]

Fender basses tend to use a compression style truss rod. It works like a bolt. One side effect of this is that it tends to compress the wood where the nut screws in.

Removing the nut and adding washers can really help. I tend to use medium strings (105-50) and quite often have to add washers, even to basses from the 90s.

And yes, with really bad necks it may be required to force a back-bow into the neck.

[flewis]

+1
I had to do the same thing because I also like a very straight neck with very little relief. I will loosen my strings, lossen the truss rod nut. Sometimes will I will need to remove the nut and add a couple of washers. This is because the wood will compress and the nut is max out on the truss rod treads.

I will clamp my neck (after loosening the truss nut first) into a slight backbow to help relieve the tension then adjust the truss rod nut. I 'll use a straight edge on the fretboard and when it will rock slighty, I know I'm there. I will then carefully tighten the nut 1/8 - 1/4 turn pass the point it was tighten to before. I mark the nut and wood area to use as reference point.

Dan Erlewine discussed this technique in the Dec 06 Issue of Bass Player. I read it a few times, got the proper tools and did it. Scare a crap out of me the first time!! I have use this technique on two of my basses so far with success.

You may be able to google and find some information on this procedure. If not, buy the Dec 06 back issue of Bass Player. Great article!

[Philbiker]

If the neck is straight, don't you guys get hellacious buzz with anywhere near usable action? Or do you just like high action? You can't get low action on a straight or near-stright neck in my experience...... Gotta have some relief.