Saturday, October 12, 2013

Adjusting Your Vintage Bass’ Truss Rod

Photo courtesy of Tim Patterson
Truss rods on many vintage basses use what is called a “cross screw” nut. This includes many early Fenders, as well as some reproduction vintage basses. The problem with the cross screw nut is that making even small adjustments to the truss rod require removing the bass’ neck.

Now most modern guitars and basses make use of hex drive nuts, which allows for easier adjustments without having to remove the neck.
The truss rod of your bass needs adjusted from time to time in order to maintain the correct bow in the neck.
Too much relief and your strings will sit too far from the fretboard, limiting the action you get from your bass. Meanwhile a back-b0w will have your strings contacting with frets, creating noise and wrecking your sound.
The ideal bow will make every note on your bass clean and playable.
The exact bow you are looking for in your bass’ neck often comes down to personal preference, with many players choosing to go with an almost straight neck with just a little “relief” in the neck.

When you have the neck off it never hurts to remove the nut and put a touch of Vaseline on the threads for lubrication. Time can do a number on those threads, and an ounce of prevention is worth a pound of cure.
Also, the strings can become a bit of a mess, getting wrapped around the head when you are taking off the neck. Save yourself the hassle by loosen each string a bit and placing a capo on the first fret to maintain enough tension to keep everything in place.
When making any adjustments in your truss rod you want to work slowly, and carefully. Make your adjustments in small increments and then test the results. You shouldn’t be turning the screw more than 1/8 of a revolution at a time.
If you hear any cracking, or for any reason are feeling uncomfortable, stop and take your bass to a local tech. The last thing you want to do is damage your neck or truss rod.
Remember the trusty “righty-tighty, left-loosey.” If your bass is too far back-bowed you’ll need to tighten the trust rod by turning right. If your bass is front-bowed it is too tight and you’ll need to provide relief, making it looser by turning left.
You must also be careful when making adjustments not to damage the cross-screw. A stripped screw will make it impossible for you to make adjustments to your trust rod.
CruzTOOLS makes a pair of rod drivers specifically for making these adjustments in vintage guitars and basses – Including a special “cheater” rod driver enabling you to make very small adjustments without having to remove your neck.

The cheater rod driver shouldn’t be your go-to tool for neck adjustments, but for a tiny correction in a pinch it should get the job done without having to go through the process of removing your vintage bass’ neck.