I'm about to try & figure that one out. I had a Les Paul Tigerized a while back by Andrew Olson. Before I started converting strats. Andrew & I didn't discuss string action (I was probably hasty), and it came back with nice low action. I didn't check the intonation at the time.
Long story short (and epic diatribe)...I decided to raise the action to Jerry standard. I built a spacer because it just didn't seem right to have the strings fret out on the harmonica bridge. I loaned the LP to Pete B. while I overhauled his Tiger/Strat (...I wish I could type Tigerstrat). I thought Pete would only have it for a couple of weeks, but do to some part sourcing issues it's been a couple of months. Apparently it's got intonation issues. The Peterson & I shouldn't have done Brother Pete wrong in that way.
Here's the odd thing. When the strings break over the saddles on a Strat...the first thing they encounter is the metal on back of the saddle/intonation slider.
I am also coming to discover that Strats only get close to proper intonation with the action set at 7/64" at the 12th fret (Gary Brawer Tiger spec). I have 3 currently in my possession. Pete's, another customers (specifically in for intonation), and my personal Stat. The low E & G strings remain slightly sharp at the 5th & 17th, with the strings shortened as much as possible (saddles all the way back). I moved the string action down to approximately 7/128th (1/2 of a 64th to the limit of my eyeballs), and the intonation improved. I think that it's very likely that each guitar type (LP, Strat, etc) will intonate best within a range. This point is likely obvious to some here, but it has been fascinating to derive that conclusion.
Can't wait to get the LP back. Everything plays into intonation. Nut. Neck relief. Dimensions of fret wire. Bridge height. Saddle position. And...likely what happens to the string once it breaks over the saddle.
I was pondering all this as I watched the Peterson spin back and forth last night. Sitting at the bench with my index finger doing the seaweed dance around the 5th fret of the G string. (Man! I really like that line!) But seriously...how you fret can effect intonation by amost 1/2 a semitone. Come to think of it...if you fretted the guitar just past the preceding piece of fretwire....it would be almost a whole semitone (genious I am
But specifically, even when you fret with your fingers touching the upper fret, the quality of the note varies greatly with pressure & position. The higher the action the more the string is lenthened by fretting.
Ok. Time for a new thread. When I have a nice tight synopsis I'll start a new thread. I should drink more coffee before I type.