Understring Radius Gauges For Guitar
- Oct 20, 2025
- 1 min read
Updated: 4 days ago
FOR EVALUATION OF FRETBOARD RADIUS
A handy guitar tool for determining the fretboard radius for regular and compound radius boards on 6-string guitars. The design allows for easier gauging of the fretboard by inserting from the bass strings side. The illustration above shows a vintage MIJ Strat which unexpectedly has a 15" radius!.
The nominal length of the understring gauges is 65mm.
The gauge should be inserted alongside a fret keeping perpendicular to the neck ensuring accurate measurement. The top radius of each gauge stem is identical to the bottom but rotated to create a widening arc along the length.
The gauges can be used as an aid for adjusting the string radius across the guitar - (where saddle adjustment permits) - and for setting pick up pole heights to the string radius.
CONVENIENT GAUGE SELECTION BY FLIPPING ROUND
The gauges are retained on a pin which provides for quick selection and progression through the radius sizes by flipping around until the correct gauge size is found.
10 individual sizes are included:- 7.25", 9.5", 10", 12", 14", 15", 16", 17", 18", 20".
