Guitar String Height Ruler
Action is one of the most fundamental parts of setting up a guitar. For you beginners out there, action is a guitar term for the height of the strings above the fretboard or guitar frets. Action plays an important role in setting up a guitar because excessively high action produces uncomfortable playing while excessively low action creates string buzz. In order to properly set up a guitar, you must be able to measure the guitar string action. That is where a guitar string height ruler comes into play.
If you have read any of my other articles, you already know that guitar action can be measured in different places on the guitar using different tools. A string height ruler is a fancy name for a 6-inch ruler that notates in 32nds and 64ths. This ruler is no different than any ruler that your would buy at any hardware store. The string height ruler is used to measure the action at the 12th fret on a guitar. This measurement is particularly important because it not only shows the action at the bridge, but it also shows the straightness of the neck. Neck relief will create higher action at the 12th fret while back bow will create lower action. To measure the action at the 12th fret place your guitar on your leg as if you were going to play it. This is important because gravity pulls the strings differently depending on your guitar's orientation. You want to measure and set up your action in the same orientation as if your guitar was being played. Once the guitar is on your leg, take your string height ruler and place it on top of the 12th fret. Standard measures for the low and high E strings are 3/32 and 2/32, respectively. You may want to lower your strings more than this, but this is a good starting point.
Needless to say, you must have a string height ruler. It is impossible to set the action on a guitar without one. Also, a string height ruler can be used to measure so many other parts while repairing and building guitars. It's really just an all around great tool to have. Plus, it's really affordable. You can get one for a couple bucks or buy a pack of three for around 10 dollars. You can go wrong with that. If you would like more information about how to set guitar string action, please see my how to set guitar string action article at guitarrepairbench.com.