Intonation adjustments on a semi floating bridge

[atarilovesyou]

....I'm new to adjusting intonation, but on my strat type style bridge, I've noticed intonation problems with the high E string. I've got the adjustment screw almost bottomed out (that is, fully 'tightened') and yet I still hear the string being out in the 17 fret and higher....

..using the standard method, if I pluck the E and hit the harm. at the 12th fret, I get the same note...yet if I fret the 12th note and pluck,it's a few cents short. In fact, when doing scales in the 12th position, I don't hear much difference, but when I go up to the 17th and beyond I do hear the difference.

I know guitars can never be completely tuned, however I've never noticed this problem before, at least not this noticeable. Could a truss rod adjustment help at all? I'm not getting any buzzes, but who knows. It's just the high E string, and I'm wondering what to do next.

Also, by tightening this screw, I'm essentially making the string longer, correct? And so, can I assume that the longer I make the string, the more 'sharp' the 12th harmonic will be, and the shorter the string, the 'flatter' it will be? I ask because sometimes while I tightened the screw, the harmonic would get higher (which was the goal) but sometimes it was like it would get LOWER as well....this kinda led me to believe that perhaps the effect is cyclical, where it's good for a while, then gets flat..and again and again until you bottom out the screw.

Sorry for the long post, but maybe someone here can help.

[john1880]

i dont think a truss rod adjustment will help.
this is the way i look at it.
think of the saddle as a fret. by moving the saddle closer to the nut, it makes the distance shorter, therefore a higher pitch. so if the pitch of the 12th fret is flat, mov ethe saddle closer, if it is sharp farther away. and on a 24 fret guitar you can do this at the 24th fret to get even better accuracy.
i think you are changing the pitch of the string, not the harmonic pitch by moving the saddle. i belive the harmonic stays the same because it is not fretted and just depends on wher you lay your finger.
hope this helps.