Mandolin action height
StewMac suggests 0.075″ (1.9 mm) on the G course and 0.065″ (1.65 mm) on the E course of a mandolin, measured at the 12th fret, with 0.005″ (0.13 mm) of neck relief and, at the 1st fret, 0.030″ (0.76 mm) under the G and 0.020″ (0.51 mm) under the E. Players with a heavy pick or a hard chop often sit a little higher.
Mandolin action, StewMac
G and E courses at the 12th fret, neck relief and nut height from StewMac's suggested settings.
| Instrument | Low (mm) | High (mm) | Relief (mm) | Fret |
|---|---|---|---|---|
| Mandolin | 1.9 | 1.7 | 0.1 | 12 |
StewMac — String Action Gauge Instructions (Suggested action settings)
How to use it
- Tune to pitch (G D A E). Measure one string of the G course and one of the E course at the 12th fret, from the top of the fret to the underside of the string.
- Enter the scale (StewMac's figures are for about 13 7/8″, 352 mm) and both readings.
- Turn the thumbwheel on each side by the amount shown, retune and measure again.
Help and explanations
Most carved-top and many flat-top mandolins have a floating bridge with two thumbwheels, so the action can be changed without sanding. The calculator turns your readings into how far to move each side.
The bridge moves twice the 12th-fret change
On a 13 7/8″ scale the 12th fret is 176 mm from the nut, halfway to the bridge, so the bridge has to move twice the change you want there. With 2.3 mm (0.091″) on the G and 2.0 mm (0.079″) on the E, reaching 1.9 and 1.65 mm means lowering the bridge 0.8 mm on the bass side and 0.7 mm on the treble side.
Back the strings off a little before turning the wheels, so they turn freely and the bridge foot doesn't slide on the top. A floating bridge also sets intonation: check that it's still in the right spot before bringing the strings back to pitch.
Relief and the nut
Check relief before touching the bridge. StewMac measures it at the 6th fret: 0.005″, with a straightedge on the frets or with a capo at the 1st and the string held at the highest fret. Many mandolins have a truss rod under a cover on the headstock; adjust an eighth of a turn at a time.
Then look at the nut. More than 0.030″ on the G side or 0.020″ on the E side at the 1st fret makes chop chords tiring and pulls first-position notes sharp. If the bridge is already as low as it goes and the action is still high, the neck angle or a sinking top is the cause, which is bench work.
Tips
- Moved the bridge? Check intonation on both courses with the intonation checker.
- Changing to a heavier set adds load on the top and the neck: compare in the string tension calculator.
- The strobe tuner shows the small differences between the two strings of a course.
Frequently asked questions
How high should mandolin action be?
StewMac suggests 0.075″ (1.9 mm) on the G course and 0.065″ (1.65 mm) on the E course, measured at the 12th fret.
How do I adjust mandolin bridge height?
Turn the thumbwheels on each side. The bridge has to move twice the change you want at the 12th fret: 0.8 mm at the bridge changes the 12th-fret action by 0.4 mm.
How much neck relief should a mandolin have?
StewMac gives 0.005″ (0.13 mm), measured at the 6th fret rather than the 8th as on a guitar, because the mandolin neck is so short.
What should mandolin string height be at the nut?
StewMac gives 0.030″ (0.76 mm) under the G course and 0.020″ (0.51 mm) under the E, from the top of the 1st fret to the underside of the open string.
Why is my mandolin action still high with the bridge all the way down?
The neck angle has changed or the top has sunk. That needs a repairer; don't sand the bridge feet, which must match the arch of the top.