Every instrument that leaves our hands is carefully scrutinized and given an expert setup. Environmental factors like heat and humidity will expand and contract your instrument's tone woods, affecting string height (action) and neck station.
Truss Rod Adjustment:
The neck should be near flat as you site down or lay the edge of ruler down the length of the fretboard on both the treble and bass edges. Bruce would add that anyone and everyone should pay attention at least monthly to "neck health" .. Under full string tension, just adjust the rod 1/4 turn at a time, check the neck as you go. The neck may groan and pop a little, but it needs to be flat or a permanent bow or dip will develop that can only be cured by a plane and re-fret. Neglected truss rods are the leading cause of poor playability and the need of neck repairs.
1. To take relief out of your neck, tighten the truss rod with an 1/8" allen wrench. (turn CLOCKWISE)
2. To relieve back-bow in the neck, loosen the truss rod. (turn COUNTER CLOCK-WISE)
Note: We changed Mandolin truss rods from single action which would use a 5/16 inch hex nut driver for truss rod adjustment, to double action truss rods which use the 1/8 allen wrench for adjustment (changed overall September, 2006). All larger body mandolin family instruments have used the double action truss rods for many years (not sure of the exact date of the change). All Arch Top Guitars and Resonator guitars have the double action truss rod.
Once the neck is flat, set the action measuring from the top of the 12th fret to the bottom of the bass string (for instance the G string on mandolins), using your Traditional Brekke Bridge Bridge tool.
Intonation, or bridge placement, is measured from the fingerboard edge of the nut, down the treble string to the inside (or fingerboard side) of the bridge saddle.
Note: If you play with a high action, your bridge placement will be closer to the fingerboard than the chart indicates.
*Make sure the neck is flat and the action is correct.
-While played open: action is too low, or nut/saddle slots incorrect
(If you've recently changed your strings, make sure your saddle is not backwards).
-While fretted a single fret: the next fret is too high
-buzzes on frets 1-5: truss rod needs to be loosened and adjust action.
-buzzes on frets 5-9: truss rod needs to be tightened and adjust action.
2. String goes sharp
-String is sticking in nut slot: first try graphite (pencil lead) in slots- slot may have to be widened.
3. String goes flat
-String is sticking in bridge slot: first try graphite (pencil lead) in slot- slot may have to be widened
-Machine heads may be worn and slipping.
-Bridge should be perpendicular to the strings
-Check the average intonation of your instrument type Here.
(If you've recently changed your strings make sure your saddle is not on backwards or that the bridge is not rocked or leaning forward)
If, while fretted at the 12th fret:
-Plays flat: move the bridge towards the peghead
-Plays sharp: move the bridge towards the tailpiece