Monday, June 21, 2010


The thing about building a guitar is you never know what a guitar really sounds like until everything is done. It's a step of faith, because if the tone stinks, there's really nothing you can do about it.

So the first time I attach strings to a guitar is both scary and exciting.

Clark's guitar sounds good.

But there is still a lot of work to be done. There's a lot of fret buzz when I play notes up the neck--specifically on the fretboard extension. Not unusual on a new guitar. I identify the problem areas, do a little filing, then re-crown and polish the frets one more time.

Now it's time for the set-up. Setting up a guitar involves making sure there is proper relief in the neck, and then setting the action at the nut and the saddle.

The pull of the strings pulls the headstock forward toward the bridge. A guitar literally wants to look like a banana. This causes relief, or a bow in the neck. Too much relief and the action is too high i.e. the strings are too high above the frets and therefore take a lot of effort to press. Too little relief and the strings will lay almost flat on the frets, causing fret buzz and dampening the tone and volume.

A straightedge laid over the frets shows how much relief there is. By putting a capo on the strings at the first fret and then fretting at the 14th fret where the neck joins the body, I create a straightedge with the string. I want there to be just enough of a gap for me to barely slide a business card between the sixth or seventh fret and the 6th string without moving the string:

There's actually not enough space, so the truss rod needs to be loosened. (The truss rod creates back bow, counteracting the pull of the strings; for more relief I loosen the truss rod and allow the strings to pull the neck forward slightly.) Just a small quarter turn counterclockwise is all it takes. I check it on the sixth string and again on the first.

A common misconception is that the truss rod determines the action or playability of a guitar; it does, but only minimally. If you have an old guitar with high action, don't touch the truss rod. You're more likely to break the rod than to dial in low action.

Action is set at the nut and the saddle. At the nut I want the strings to barely clear the first fret. The strings are stiffest here, so you don't want to have to press them down that far, but because they are stiff in this area the vibrations occur in a very small arc, facilitating low action.

I have a set of feeler gauges that I use to set the nut action. I make a stack that is equal to the height of the first fret plus .016". I place the feeler gauge up against the nut and file the string slots down to it. I use a special set of files to match the different string gauges.

I angle the file to match the angle of the headstock, ensuring that the break point of the string is at the front of the nut. After all the slots are cut, I take the nut out and file the top in a gentle curve. I want the two unwound strings to be barely buried in the slot, and I want about 1/2 of each wound string to sit in the slot. After this I sand the nut down to 600 grit, which gives it a polished but not plastic look.

The action at the saddle was actually set with the poster board shims, but I check it anyway.

Looks good.

Plays good.

Sounds good. But there's one more thing to do to make it sound even better--and it's one thing that the big factories can't afford to take the time to do.

But you'll have to wait.

No comments:

Post a Comment