Relief Gauge

For the greatest accuracy take these measurements with the guitar resting on its side in the playing position. (Our #5252 Neck Jig is a great tool for holding and tilting the guitar for reading and adjusting a neck accurately.)

“Zero” the indicator on a flat surface, or against an accurate straightedge. Center the beam on the fretboard between the D and G strings, with the dial plunger contacting the seventh to ninth fret area. As you tighten or loosen the adjusting rod you will get a plus or minus readout, in thousandths of an inch (photo 2). Because of the shape of the indicator rod's cap, slight tipping from side to side will not affect the tool's readout.

Another way to use the gauge is to preset the indicator for the desired neck relief. The gauge can then be used to check the results of your truss rod adjustments. Hold the neck firmly with one hand, and the gauge firmly with the other, for a quick reading; this is helpful if the guitar is tipped over into the playing position but not clamped firmly. Then set the gauge down to make your adjustment and keep checking until you get the desired readout.





Neck resetting or saddle slot routing
When resetting a neck (photo 3) or routing a saddle slot, the bridge and saddle can be raised to simulate string tension.

This will eliminate guesswork during a reset, and guarantees a flat saddle slot bottom when routing. This is especially important when installing an undersaddle transducer pickup. In photo 4, a brace jack rests on a piece of wood spanning the braces. The jack gently pushes the bridge area up to the dial indicator measurement previously recorded when the strings were at standard tension.

Rest the gauge as close to the outside rim of the guitar as possible. Center the indicator plunger over the appropriate area of the bridge—the soundboard just in front of the bridge, the bridge body, or the top of the saddle (photo 5). Zero the indicator, and then set the gauge aside while you remove the strings. When you're ready to work, raise the jack until the guitar's belly is under simulated string tension and the indicator reads zero.