With the Floyd Rose being designed as a "floating" system, the bridge should pivot in the grooves on the rocker screws (mounting posts) and these should be the only two places it touches the guitar. The bridge baseplate is supposed to be parallel with the body of the guitar. If the baseplate is not parallel, then a few adjustments must be made.
If the rear of the Floyd is sticking in the air, away from the guitar's body, the tremolo springs in the rear cavity of the guitar are too loose. If the Floyd is pointing toward the body, then the tremolo springs are too tight. To make this adjustment, you must remove the tremolo spring cover and adjust the spring tension by moving the spring claw. If the springs are too tight, just turn the two screws to the claw counter-clockwise a little. If the springs are too loose, loosen the strings (to avoid breaking one), and turn the two screws clockwise. You will now have to retune and check the bridge for being parallel (Fig BT1). This will have to be repeated many times until the bridge is parallel with the body when it is in tune. This procedure must be performed each time string gauge or alternate tunings are used.
Once the bridge is parallel with the body, check the guitar's action. To do this, I play every string at every position to check for string buzz. If you do not get a buzz, lower the bridge height by turning the mounting posts clockwise (Fig BT2) into the body a portion of a turn, and then recheck for a buzz at any position on the neck. If there is a buzz, you will want to raise the bridge by adusting the mounting posts counter-clockwise. To get the lowest possible action, perform this operation several times until you have the strings as low as possible without a string buzz. You may also adjust only one side of the bridge at a time.
*Note - There are three different heights of
saddles to compensate for the radius of the
neck's fretboard. Some of the earliest Floyd
units have saddles of the same height, so a
metal shim is placed under the middle four
saddles, so if you are having problems
getting good action, the saddles may be
rearranged or the shim has been removed.
If you are still having some problems with getting a decent action on your guitar, there are many other factors that may be contributing to this. Some problems that cause this are excessive fret wear, a bow or arch in the neck, the locking nut is too low, or the neck is not mounted in the optimum position on the body.
One of the best ways to check for excessive fret wear is to look at the individual frets and make sure that they are uniform. The "crown" on the fret should be uniform through its whole length. If the fret has wear "dimples" in the fret, or the crown is highly worn on one side (usually the smaller gauge strings from doing string bends), then it may need a fret-dressing or a fret-job. These two repairs should be performed by a qualified sevice tech.
To check and see if the neck has excessive bow or arch to it, fret the low "E" string on the first and last frets on the neck. The neck should be almost straight with probably no more than a 1/64" bow in the middle of the fretboard. In Figure BT3 below, "A" shows a dramactic bow in the neck and "B" shows a dramatic arch.
A neck with a bow in the neck will cause bad action and wil also impair intonation. An arch in the neck will cause string rattle and false tones. Adjusting the truss rod can make a HUGE mess of your neck if you do not have experience with it. You can do some serious and irreversible damage to a neck if you over adjust a truss rod. You may want to take the guitar to a qualified service tech for a truss rod adjustment, but Figure BT4 below gives you an idea of how to adust it.
The truss rod adjustment nut is usually found in the headstock of a tilt-back design headstock neck ("banana" and "pointy" headstocks) or between the body and neck ("strat-copy" and "classic" headstocks). The one in the headstock is usually under the truss rod cover, unless it is a Fender-type "bullet" truss rod. The adjustment nut between the body and neck usually requires the removal of the neck to adjust it. this should give you an idea as to how rare a truss rod adjustment usually needs to be performed.
Sometimes you may notice a lot of buzzing at the first few frets. This is caused at times by a worn nut. Over time, the strings will wear grooves into the nut thus reducing the height of the locking nut. If this occurs, instead of just replacing the nut, it is sometimes necessary to raise the nut. To do this, remove the two screws on the rear of the headstock. You can now place a shim under the nut. The shim can be made of just about any material from thin cardboard to an old guitar pick or a folded over piece of masking tape to actual metal shimming material. Make sure that there are holes through the shim to allow the two mounting screws to go through. The height of the nut shim will be a trial and error experience, as is just about everything else on adjusting the Floyd Rose unit.<
This last suggestion is a necessity for some and not even possible for others. At times, a reangling of the neck is needed. With a bolt-on neck, this is easy to do, but it is impossible with a neck-through. If you want the Floyd at a certain height from the body or you want to bottom the Floyd on the body of the guitar, this is how you would go about doing it.
To reangle the neck for the purpose of raising the Floyd off of the body, you will have to remove the neck and place a shim under the neck closest to the bridge (see "A" in Figure BT5). An old guitar pick held in place with masking tape or thin cardboard works great for this. You only want a slight tilt in the neck, and this will be visable when the neck is replaced on the body by looking at the edge of the fretboard in comparison with the upper surface of the guitar's body. To lower the Floyd closer to the body, either make sure that the neck is flat in the neck pocket, or even raise the rear of the neck by shimming the rear of the neck pocket (see "B" Figure BT5).