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Some guidelines for the action
Distances between the top of the 12th fret and the bottom of the strings:
For guitars: 1.5 - 2mm (4/64" - 5/64") For basses: 2.5 - 3mm (6/64" - 7/64")
move a string sideways it must not move at all in the nut. The strings must be bent right at the nut edge and there must not be any sharp edges anywhere either that could possibly damage the strings. Only one half of the strings should actually be in the slots; the top half of each string should protrude.
Setting the action
The action is the distance between the frets and the strings, which is usually measured at the 12th fret. Setting it is always a compromise between a low position – the lower the action, the easier the guitar is to play - and a high-enough position to keep the strings from rattling against the frets. Before the action is set the frets obviously have to be filed level (see above).
When the action is set high, the guitar is less likely to make unwanted noises but is also less comfortable to play as more pressure is needed to press down the strings. Intonation also suffers from an action that is set too high, and the neck will be more strongly exposed to the bending forces. Finally, the height of the action also depends on the way the instrument is played: somebody who strikes the strings forcefully will no doubt need to have the action set rather high. On electric guitars the action is set lower than on acoustics - electrics sound quite loud already even when struck only lightly.
Put the guitar into the playing position and place a rule with a zero-mark right at its edge onto the 12th fret (as shown in picture 1) and measure the height to the lower edge of each string. You can also use a feeler gauge or short pieces of scrap strings for measuring. Then slowly set the action on the bridge to the desired height. On most bridges the action can be set with a small allen key (2). The saddles should remain approximately horizontal. Other types of bridge can only be adjusted for height as a whole by means of wheels; individual strings can then only be raised or lowered by filing down individual saddle slots. On radiused fingerboards the action has to follow the radius.
You don't have to set all strings to the same height; the thinner, more highly tensioned treble strings vibrate less and can therefore be set lower than the bass strings. As a guideline set the action so that it increases from 1.5mm (4/64") at the treble E string to 2mm (5/64")at the bass E string on a guitar. The values given here are just guidelines, but obviously the action can always be set lower if the style of playing and the frets permit. Since the strings on basses vibrate more strongly, the action has to be set higher as well, namely to 2.5 to 3mm (6/64" - 7/64"). These figures are only averages and can, of course, be slightly varied according to the personal requirements of the individual player. All adjustments have to be checked after a couple of days when the neck has adapted to the action.
After tuning check each string at each fret for unwanted noises. If any such noise can be heard on an open string, the string probably doesn't rest properly on the nut or the bridge. Often nut or bridge slots that have not been given enough attention are the reason for noises sounding like rattling on the frets. If the noise disappears when you additionally press down the string behind the nut, the problem can be attended to by carefully filing the guilty nut slot, or, if that is no longer possible, by replacing the nut. So find out first what causes the noise before you raise the action or start working the frets with a file.
If a fret turns out to be the cause of the problem, try pressing down the string at all frets, starting at the first and then working your way up the fingerboard. The fret at which the rattling noise disappears is the cause of the problem: it is too high and must be filed down carefully. But quite often the guilty fret is not all that obvious; it may well be situated in a totally unexpected area. The electrical conductivity of steel strings can be used to find out any frets that are too high. Hold one probe of an analog ohmmeter to the string behind the bridge or the nut. Then pluck this string and hold the second probe to one fret after the other. Wherever the string touches the fret an electrical current can flow and the ohmmeter needle will move and show a low resistance value.
If there are unwanted noises caused by the frets, the strings have to be removed again and the guilty frets have to be redressed. Fasten any loose frets with a blow of the fretting hammer or by gluing them down with super glue.
Setting the action
on radiused fingerboards
On radiused fingerboards the action has to follow a radius.This means that the saddles on the bridge have to be set higher in the middle. The action has also to increase from the treble to the bass string.
Adjusting the pickup height |
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By adjusting the pickup height (3,4) you can balance the sound |
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of the instrument. Pickups that are close to the strings give a |
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greater output and make the guitar louder and bassier. The |
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closer the strings are to the pickup, the greater the effect of |
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magnetic interference on the strings' vibrations, and in particu- |
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lar on the wound strings, will be. The clarity of the sound will |
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suffer as a result of the strings no longer being able to vibrate |
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freely. So a compromise between minimum interference and |
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maximum output has to be found. The traditional single-coil |
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pickup with strong magnets right inside the coil is particularly |
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affected by such unwanted interference. This is why single-coils |
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should never be fitted closer than 3 to 5mm (1/8"- 3/8") to the |
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strings. This does, however, not apply to active single-coils, |
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which don't have a strong magnetic field. Humbuckers with |
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magnets under the coils have to be mounted 1.5 to 3mm (1/16"- |
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1/8") from the strings. The pickups should not be mounted |
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further than necessary from the strings as this only reduces the |
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output and weakens the pickup signal in relation to the level of |
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electrical noises such as hum. To ensure that both coils of the |
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humbucker are at equidistance from the strings the pickup has |
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to be adjusted parallel to the strings (1). For this purpose the bottom side of the mounting ring may have to be shaped accordingly.
Now play the guitar and listen out for strings that are louder or basses that dominate. Ideally, all strings should produce the same level of volume. To compensate for any differences in volume level between the thicker and thinner strings or to boost bass or treble tones the pickup can also be set lower under the bass strings than under the treble strings. The closer the pickup
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is placed to the strings, the more the basses will be boosted. The output volume of individual strings can be increased or
reduced by means of adjustable polepieces. These should, if possible, also be set following the fingerboard radius. If the guitar has more than one pickup, a good balance between the individual pickups should be aimed at as well. A pickup moun-
2ted on the bridge produces less output; by fitting it closer to the strings or setting the front pickup lower it can, however, be made
to sound as loud as the front pickup.
Setting the intonation
The intonation can be set by ear or with a tuner. The purpose of setting the intonation is to make the pitch of each string at every fret as accurate as possible as far as the equal-tempered tuning system allows. This is necessary to counteract the increase in pitch which results from the strings being tensioned when
3pressed down. The treble strings are more affected by this than the bass strings. To compensate for this change in pitch the length of the freely-vibrating strings has to be increased slightly. With a chromatic tuner you can check the pitch of each individual string at each fret. In doing so you will find that the amount of pressure with which the strings are pressed on the fingerboard strongly affects their pitch. Reaching a precise pitch is virtually impossible if the action is too high. In that case you will only get it by pressing the strings only lightly and exactly onto each fret. This is why, as already mentioned above, the action should be set
rather low. The height of the 4 frets also has an influence on
the pitch of a string that is pressed down: the higher a fret is, the more the strings will be tensioned when pressed down and the more they will go out of tune.
Tune the guitar and compare the pitch of a string pressed down at the 12th fret (2) and its harmonic at the
12th fret. This harmonic is exactly twice as high in pitch as the open string and should also be identical in pitch with the string pressed down at the 12th fret. The job now is to make the pitch of a string pressed down at the 12th fret exactly the same as the pitch of its respective harmonic. If the pitch at the 12th fret is lower, the vibrating length of of the string is too long and has to be reduced by moving the saddle. If, on the other hand, the string pressed down at the 12th fret sounds higher than its harmonic, its vibrating length has to be increased (3,4). Any changes made at the bridge to increase or reduce the vibrating length of a string will also inevitably change the tuning of the string. So before you continue checking the intonation make sure to tune the guitar first. Carry out this procedure for each string or pair of strings, depending on which bridge you use. To set the intonation very accurately hold the guitar in the playing position as gravity can have an influence.
Correctly-adjusted bridge
In the picture above you can see the typical saddle arrangement of an electric guitar with “normal” action after the intonation was correctly set.
Your self-made guitar
So there we are: the long, hard work of building your own electric guitar has borne fruit – it is finally finished. Even if the action should change within the next few days or weeks and the whole setting-up process should have to be repeated, don't worry too much about it: it is normal for a guitar to take some time to adapt to the pull of the strings and to reach a balance.
All the guitar needs from now on is careful treatment and sufficient attention. Expose it to cold, heat or moisture and it will suffer. It dislikes sudden changes in climate as much as being left lying in a car overnight, and it is best transported in a case or a well-padded bag. Musical instruments have, in that respect, a mind of their own, but they
will be faithful and reliable friends and reward the loving care they are given with a beautiful sound.
Send me a picture of your self-made guitar
If you have come this far and you are a proud owner of a self-made guitar, it would be great if you could send me a photo of it (either on real paper or in electronic form). I would like to show it together with a short description on my web site: www.BuildYourGuitar.com
Enjoy the first guitar you have built yourself. I would be surprised if it were to remain the last …