String action refers to how high the strings sit above the frets. Proper string action is essential for playability, tone, and comfort. If the strings are too low, they may buzz against the frets. If they’re too high, playing becomes difficult and intonation may suffer. This guide explains how to measure and adjust string action using the bridge and truss rod, with specific instructions for electric and acoustic guitars.
What Affects String Action?
- String Gauge: Heavier strings exert more tension, potentially raising the action.
- Tuning: Alternate tunings can change neck tension and affect action.
- Climate: Humidity and temperature shifts can cause wood to expand or contract, altering string height.
Guitar Type-Specific Setup Notes
🎸 Electric Guitars
- Bridge Adjustment: Use an Allen wrench to raise/lower individual saddles.
- Truss Rod Access: Usually located at the headstock under a cover plate.
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Common Setup Range:
- 1st fret: 1st string = 1/32", 6th string = 1/64"
- 12th fret: 1st string = 5/64", 6th string = 3/64"
🎻 Acoustic Guitars
- Bridge Adjustment: Typically not adjustable per string; saddle may need sanding or replacement.
- Truss Rod Access: Found inside the sound hole or at the headstock depending on model.
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Common Setup Range:
- 12th fret: Bass strings = 6/64", Treble strings = 4/64" to 5/64"
🧪 Hybrid or Specialty Models
- California & Retro Series: Truss rod access above the nut.
- 66 Classic & DLX: Truss rod under a small plate on the headstock.
- AB Acoustics: Truss rod accessible from the sound hole.
Measuring String Height
Use a ruler to measure string height at the 1st and 12th frets:
| Fret Position | 1st String (High E) | 6th String (Low E) |
|---|---|---|
| 1st Fret | 1/32" | 1/64" |
| 12th Fret | 5/64" | 3/64" |
These are typical values for electric guitars. Acoustic guitars may require slightly higher action.
Truss Rod Adjustment
The truss rod is a metal bar inside the neck that counters string tension and allows curvature adjustments.
- Turn Counter-clockwise: Loosens tension, raises action.
- Turn Clockwise: Tightens tension, lowers action.
- Best Practice: Adjust in ¼-turn increments and allow the neck to settle for 5 minutes before re-tuning and re-measuring.
Bridge Adjustment (Electric Guitars Only)
If only one string is too high or low:
- Use the correct Allen wrench.
- Raise or lower the saddle until the desired height is achieved.
- Re-tune and test playability.
Setup Steps Summary
If Strings Are Too Low:
- Turn truss rod counter-clockwise (¼ turn).
- Let neck settle for 5 minutes.
- Re-tune and measure.
If Strings Are Too High:
- Turn truss rod clockwise (¼ turn).
- Let neck settle for 5 minutes.
- Re-tune and measure.
Final Check
When your guitar feels comfortable, sounds clean, and has no buzzing or resistance, your string action is properly set.