First we should get a feel for adjusting the rod itself. All adjustments to a truss rod should be done by turning the nut as little as possible. Let's starting by loosening the nut. Turn the nut counter-clockwise until it just starts to move. You should never try to turn the nut more that 1/8 of a turn. Check the neck to see if it looks different. Loosening the rod should cause the neck to bow more. If the neck hasn't changed, loosen the nut a bit more until you can see a change. Site down the side of the neck or use a straight edge to see if the neck has changed shape.

Now let's tighten the nut back to where it started. Turn the nut clockwise until it starts to move. You should be able to turn the wrench the same amount as when you loosened the nut without having to force it very much. Check the neck again to see if it has changed. It should be back to the same position as when you started.

If you need to actually adjust the rod you follow the same basic method. If the neck is bowed too much, tighten the rod a little at a time checking the result as you go. If it has a hump that is causing strings to buzz, loosen the rod. If everything is working as it should and there are no major problems with the neck, you will not need to tighten the neck as much as 1/16th of the turn. Just apply enough force to make the nut move and keep checking the neck.

A truss rod is not designed to fix neck problems. It's only job is to balance the pull of the strings. If you tighten or loosen the rod and the banjo still is very hard to fret or it buzzes a lot take it to a professional for help. For setup purposes the ability to monitor the neck and make seasonal corrections using the truss rod is a very handy thing to be able to do. A slight problem here can have a big impact on the overall sound and playability of the banjo.

Finally, I want to talk about another aspect of string height as it relates to adjusting the truss rod. In general, having high action tends to increase volume and low action lowers volume. This is because the string has more space to vibrate in without hitting the fingerboard. Also, you can pick the strings harder without making the strings buzz. If you like to pick very hard, you probably want to keep the action higher than if you pick more softly. However, there is another factor to string height you might not be familiar with. The overall tone of the banjo can change very noticeably as the height of the strings changes.

There's no way to quantify this change except trial and error but here are a couple of things to keep in mind. If the strings are very close to the fingerboard they will not only be softer when you pick and fret them but they'll also tend to sound brighter and less well defined. In the extreme case they will buzz most or every time you pick a string. If you don't pick hard you might not notice this especially is you just play around the house. If you do play with other instruments you'll probably pick harder and find that the banjo doesn't carry well so you just pick even harder and so it goes.

In my own experience I've found that sometimes when I pick up the banjo up to practice or jam it sounds kind of thin and the strings feel either too stiff or too floppy. It sounded and played really great the day before and I hadn't done anything to change that. There are several things that could have caused this, but one of the most frequent ones is that the neck has moved one way or the other. The first time I look down the neck it doesn't seem different from the day before. If I keep looking (be sure you have good light when doing this) I often finally see that the neck bow has changed in one direction or the other. Usually the change was very small which was why I couldn't spot it to begin with. Tightening or loosening the rod the smallest amount possible often makes it sound and play way than it had the day before.

Sometimes, especially when the weather is changing rapidly, you need to check the rod and adjust it every day or two for a week or more until it settles down. Many people lack the compulsiveness necessary to take this aspect of banjo setup to the bitter end. I just want to let you know it's possible. I'll close this section by mentioning that I haven't had a truss rod cover on my banjo for a couple of years now....

Here's a recap things to keep in mind before really trying to adjust your truss rod:

1. Loosening the rod is much safer than tightening it.
2. Don't try to turn the nut more than the smallest amount without checking the results. This applies to both loosening and tightening.
3. If the nut won't turn without applying a lot of force, STOP!
4. If tightening or loosening the nut doesn't fix the problem with the neck, take the banjo to a qualified repair person.