ELECTRIC GUITAR ACTION
Electric guitar action is similar to acoustic guitar action, but the strings are usually lighter gauges, closer to the fingerboard, and there is more hardware to adjust. The nut, neckrod and saddle adjustments are all interrelated, changing one requires changes to the others. The electronic circuitry can sometimes be a factor that affects tuning. Additionally, the bridge usually has separate pieces to adjust for correct intonation. There is an enormous variety of bridge designs on electric guitars and the adjustments can be confusing. Also, there are a number of different types of neck rods and they sometimes can cause structural problems. With the lighter gauge strings, tuning becomes more difficult to maintain and so the adjustments are much more critical. Electric guitars also vary more in their scale lengths and it is important that players have a good understanding of how scale length affects tuning, playability and choice of string gauges. If you consistently use alternate tunings, you should have the action set for the tuning used on each instrument.
Because there are three plain treble strings, the frets wear in a different manner than acoustic guitars. Most players bend the plain strings across the fingerboard around the octave(12th fret) more than any other area. The constant rubbing of the plain steel strings against the softer German silver fretwire tends to flatten out the tops of the frets over time. When the whole width of the fret has flattened, the string is no longer pressing on the center of the fret position, and is now off to one side. This has a noticeable effect on tuning. Leveling the frets and recrowning them can solve this problem. When the frets have been leveled a number of times, they reach the point of having to be replaced.
Guitar fingerboards vary in their curvature. Older guitars often have a more rounded radius and this will cause the notes to "fret out" when bending strings. With this situation, removing the frets and flattening out the fingerboard is the only answer. This also means the guitar has to be refretted.
When in a standard tuning, electric guitar action is usually set at 1/16" off the 12th fret, measured from the top of the fret to the bottom of the string. Neck relief is adjusted by the neck rod. Place a capo on the first fret, hold the low E string down at the 14th fret and measure the space between the 7th fret and the string with a feeler gauge. It should be about .008". Nut height on guitars is about .020" between the top of the first fret and the bottom of the string. You can check these dimensions with a 6" machinist ruler and an automotive feeler gauge. Unlike acoustic guitars, electric guitar bridge height can vary as much as is needed to properly set the action. It is very rare to reset the neck on an electric guitar. With Fender style necks, the screws can be removed and shims placed into the neck pocket to adjust the neck angle when necessary.
Setting the intonation adjustment at the bridge is the final step with electric guitar action. The pickup design may cause a problem when setting intonation and the pickup height must be determined first. Humbucking pickups have two coils that are mounted on top of a magnet or group of magnets. The pole pieces are steel and the proximity of the magnets to the strings will not cause a problem with tuning. With double coil humbucking type pickups, hold the strings down at the last fret and turn the adjusting screws so the top surface of the pickup is about 3/32" below the strings. If there is no cover and the plastic bobbins are exposed, drop the neck pickup down a little lower on the treble side. When bending the high “E” string, sometimes the string will snap around under the edge of the bobbin and damage the windings.
With single coil Fender type pickups this adjustment is a little more difficult. On these, the individual pole piece located beneath each string is a separate magnet. If the magnet gets too close to the string, it will pull on the string and knock it out of tune. This effect is more noticeable as you play up the fingerboard. The magnets have varying strengths and they are preset at different heights depending on their design and when they were made. The general rule of thumb is to hold the strings down at the last fret and set the pickup to 1/8” on the treble side and 3/16" on the bass side.
After all this is taken care of, and with a brand new set of good quality strings on the guitar, the intonation can be set. Tune the guitar with an accurate electronic tuner. Starting with the low E string, check that it is in tune and play a harmonic on the 12th fret. Press the string down at the 12th fret and check to see if it is flat or sharp compared to the harmonic. If it is flat, adjust the bridge piece forward (toward the neck). If it is sharp, adjust the piece back (away from the neck). Repeat this process with the remaining five strings.
