A radius gauge is used to compare the height of each string in respect to the radius of the fertboard. To optimize your guitar’s playability, it is recommended that the string heights should match the radius of the fret board. Click here if you are unsure of your guitar’s radius.
1. Find the radius gauge that matches the arc (or radius) of your neck. Radius gauges usually come in a set so if you’re not sure which one to use, try a few and pick the one that best matches the arc of your fretboard.
2. Use a ruler graduated in 32nds or 64ths of an inch to measure the height of the top and bottom E strings. Set the height of these strings to your preferred action height first.
Tip: While specifications vary among guitar manufacturers, common heights are 5/64ths for the low E string and 4/64ths for the high E string.
3. Set the gauge on top of the strings next to the bridge. Since the high and low E strings have already been adjust, raise or lower the height of the four inner strings until they make contact with the radius gauge.
Tip: If all of your strings are set to the same height, this will also achieve the proper radius.