FUQ (eff -yu - cue) - FAQ's with an EDGE

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Question:
I have a question about what those screws on the bridge are for? I'm guessing that they're involved in the tuning of the guitar because I adjusted mine and now I can't get it back to normal. i.e. my guitar is extremely hard to tune and possibly never can be in tune. I was also wondering if anyone could tell me how to put my guitar back to tune as well. My friend says I need to lock the bridge again, but I don't know how to do that.

Answer:
I suggest talking with your nearest guitar tech and read lots of magazines and repair and setup books. That way, you can be your own tech and no one else can touch your beautiful axe! That's what I do... The thing that u lost(tuning) is called intonation. Yep, it'll screw shit up real quick if u mess w/ the screws without knowin what your doin. If u know what Harmonics are and have a digital chromatic tuner you should be able to fix this dilema. Plug your axe into the tuner. 1.) Tune all the strings w/ the tuner, leaving all strings open(E,A,D,G,B,E).  2.) Now start intonating the low E string by producing  a harmonic at the 12th fret THEN pluck the string open(no freting here). 3.) You want the open note and the harmonic to TUNE to the same note(E). 4.) To bring the harmonic and the open note to the same note(E) you have to adjust the screw. It takes some time to get it right and I also need to stress that you need to intonate the string at E not Eb or F.  5.) Note that when you adjust the screw one way it may bring up the note of the harmonic and have a reverse affect on the open E note. Just use your tuner and pay attention to the affect of the screw adjusting and the affect to the harmonic and open note.  But if all else fails take your axe to a guitar or music store. Chances are they'll do it right there and then for next to nothin. So, your guitar is FUBAR now, eh?  There are ways to get it back to normal, was it normal before you started messing around with it?  Have a really good look at the saddle screws and figure out what they do before you attempt to change things. First off, you have to correct the intonation.  Get a tape measure and measure the distance from the leading edge of the nut to the middle of the 12th fret.  That distance should be the same as from the 12th fret to the bridge.  If it isn't then you can turn the bridge saddle screw(s), those are the ones at the back of the saddle, to correct it. Check your intonation by plucking the open string and comparing it with the note on the 12th fret. Should be the same except the 12th fret is an octave higher. Do that with every string.   Next you have to setup the action. If your strings are buzzing then the saddle(s) are too low.  If the action is too high then the saddle(s) are too high.  The screws on top of the saddle(s) are the ones for correcting your action.   Close, but no cigar. The 12th fret harmonic will _always_ be exactly an octave above the open-string note. Such is the nature of harmonics. What's required is to adjust so that this harmonic and the 12th fret fretted note match. If the fretted note is sharp, move the bridge away from the neck. If it's flat, move it toward the neck. Adjusting the height of the strings will also affect intonation, because when you fret the string you're also stretching it slightly. Just like bending a note, except you can only go so far before you hit the fretboard. So to be really on, if you mess with string height you also have to mess with intonation. String gauge is also a factor in both these adjustments. So if you change to a different gauge of strings, you should re-adjust. Not quite...FIRST set up the action. Raising or lowering the strings will affect the intonation! This is because fretting the string also stretches it-- like bending a note, except you run into the fretboard before you bend it very far. Which is also why you can't set the string length with a tape measure. The 12th fret is actually a little closer to the nut than halfway, by an amount that will vary from string to string. (the fatter strings need more compensation as a rule, just as they'll want to be set up slightly higher). The key is to get the 12th fret fretted note to match the 12th fret harmonic. If the fretted note is sharp, move the saddle away from the neck. If it's flat, move it toward the neck. As you make these adjustments, the open string note and the harmonic will also change, of course, but at a slower rate. So eventually you will be able to bring the 12th fret note and harmonic into sync. Using a tuner with a dial, as opposed to led's, is helpful because you need only compare the notes. If they both put the dial to the same point, even if it's not precisely an E, for example, you're there. Once setup is completed you can worry about tuning the string to exact pitch.