I just got a MIM strat from a friend and all the strings but the A string are intonated, the A is always 20 cents sharp wherever I turn the saddle screw. Now I read in another topic of shortening the screw, how would I go about this?
what you need to do slacken your string and turn the screw that moves your saddle away from the headstock a touch then retune. play an open note the fret at the 12th fret they shoud be the same or as close as poss, this may take a few goes depending on how fussy you are, though you may not be 100% bang on
http://www.projectguitar.com/tut/intonate.htm there you go