I lowered my silverburst lp after putting on the strings.
Measure how much lower you want the strings after and ONLY AFTER you have put on whatever strings you will be working with.
(for example; if you measure with "slinkys" and then put on "fat-bottom, skinny-top" strings you're going to have a LOT of fret buzz....like I did with my second guitar.)
After you measure the distance between the string and the frets at the second fret, take that measurement and mark the bottom of your nut (where the seat of the nut meets the neck-top) at HALF of that measurement.
(NOTE:We only take a HALF measurement at the nut because the bridge will perform the other HALF of the lowering effort)
Now, remove the strings from your guitar. Then carefully use a razor or boxcutter to get the laquer or glue from around the edge of your nut where it is seated on the guitar neck, being careful not to nick your neck. Then gently and carefully tap-out your nut with a wooden dowel (Pencil cut in half) and rubber hammer, bracing the neck and body of the guitar.
Once you've got your nut out, clean off the glue from the bottom and back of the nut.
Measure the HALF-DISTANCE you got earlier from your fretboard-strings and mark that distance on the bottom of your nut where it would sit on top the neck.
Now find a flat surface and a piece of fine-grit sandpaper.
Lay the nut down on the sandpaper and rub the nut on the sandpaper until the bottom matches the HALF-DISTANCE measurement you marked on the nut earlier. (That flat surface is HIGHLY important for this part because if the surface is curved in ANY WAY...your nut will sand down curved...and that is very very bad...)
After you are finished, clean the nut with alcohol and let it dry.
Then mount the nut back onto it's place on the neck with elmers glue and clean any excess glue off of the neck. Make sure to use something to clamp the nut in place for 2 hours until the glue is completely dry.
[2 hours later]
(ELECTRIC)
Now, restring your guitar and you will notice that the strings are closer to the fretboard at the head of the guitar. This will help you play easier and faster without the strain encountered at the head of the guitar near the nut. If you have a Gibson guitar, you can use the adjustable bridge to fine tune the second half of the lowering process as you see comfortable.
After lowering the strings to the height you require using the bridge adjustments....retune the guitar and check intonation at the open position and 12th fret on each string. Each open tone should be an octave lower than the tone at the 12th fret.
(ACOUSTIC)
Remove the saddle from your bridge...you know, that little white or cream colored insert.
Measure the HALF-DISTANCE you got earlier from your fretboard-strings and mark that distance on the bottom of your saddle where it would sit inside the briege.
Now find a flat surface and a piece of fine-grit sandpaper.
Lay the saddle down on the sandpaper and rub the saddle on the sandpaper until the bottom matches the HALF-DISTANCE measurement you marked on the saddle earlier. (That flat surface is HIGHLY important for this part because if the surface is curved in ANY WAY...your saddle will sand down curved...and that is very very bad...)
Now, restring your guitar and you will notice that the strings are closer to the fretboard at the bottom of the guitar. If you require the strings to be closer, mark the half-distance on your saddle again and sand it down. Use small increments when sanding because if you go too far...you will have to replace the saddle and start sanding all over again.
After lowering the strings at the saddle to the height you require, retune the guitar and check intonation at the open position and 12th fret on each string. Each open tone should be an octave lower than the tone at the 12th fret.
Once everything is in tune...your guitar has been successfully lowered.
=]
Dm
"Talent instantly recognizes genius,
but mediocrity knows nothing more than itself."
-Sir Arthur Conan-Doyle