The bridge ( sometimes called the saddle ), is not only adjusted for height, but also to level the bridge with the neck.
But before we get into the differences in adjusting them, first let’s discuss what we are trying to achieve.
I will start by giving you the manufacturer’s suggestions on the height of the strings. One dimension is for the 6th string (or bass string) and the other is for the 1st string (or treble string).
Their measurement is taken at the 12th fret and is measured from the top of the fret to the bottom of the string. You can use a ruler to measure it.
Bass String 5/64″ Treble String 3/64″
Their measurement is taken at the 14th fret and is measured from the top of the fret to the bottom of the string. You can use a ruler to measure it.
Neck Radius Bass String Treble String
7.25″ 5/64″ 4/64″ (or 1/16″)
9.5″ – 12″ 4/64″ (or 1/16″) 4/64″ (or 1/16″)
15″ – 17″ 4/64″ (or 1/16″) 3/64″
Remember that this is their recommendations and since all of us are different, I feel it is a good starting point, but don’t assume that this is the only place it can be. If you feel like you want it a little higher or lower, by all means, try it. How else are you going to know what feels best to you? However, they have that standard for a reason. I do feel you should start there and see before you just start trying something else.
There are a lot of different types of bridges. I am not going to discuss all the types, but I am going to discuss the basic types.
Almost all acoustic guitars have a fixed bridge. This being a thin piece of plastic. The reason that this style of bridge is so popular on acoustic guitars is because it is the vibration of the bridge against the body of the guitar that makes the sound. Unlike electric guitars that use pickups to relay the string’s vibrations.
These bridges may be straight or compensated. The difference being whether they are a straight piece or not. The reason that they aren’t straight is to try to compensate for intonation (which we will discuss in another lesson). This type of bridge is adjusted by taking them out of the guitar and sanding the bottom of the bridge to lower the action, or shimming it up (by placing a piece of paper or cardboard under it) to raise the action.
There is also this style of bridge which is adjusted with a thumb screw to adjust the height on both sides of the bridge. This makes adjusting the height easier, but by the nature of the mechanism, some of the vibration is lost and therefore tends to be a quieter guitar.
Electric guitars incorporate all sorts of bridges. Different manufacturers patent their own style and many are unique and elaborate.
Others are more common.
The bridges are sometimes adjusted by thumb screws on each side (like the one directly above), and others use screws to adjust each individual saddle (like the one below).
When you adjust the individual saddles, you should adjust the height of the bass string and the treble string first. Then take the neck’s arch into consideration to connect the two. Some necks are very flat from bass to treble sides while others are domed. Follow the flow of the guitar and it will feel more natural as you play it.
Next, let’s go on to Adjusting the Intonation.