Laudiesdad69 wrote:I don't know if this is right anymore, but I was taught by my luthier friend (he apprenticed under Dan Earliwine) that when testing the intonation to check the 12th fret fretted note with the open string note. Not to check the 12th fret harmonic note to the 12th fret fretted note because of the distance of string travel to the fretted note will cause the note to be off (sharp). The 12th fret harmonic is on a flat plane that doesn't require string deflection to sound the note. Without being able to adjust the string length, all you have to work with are the saddle, nut, and thickness of strings. Unless you have a truss rod like on an electric or steel string.
Righto...I have Dan Erlewine's book on guitar repair. When I check using open strings, the notes are still sharp at the 12th fret, though the G string is relatively close (with the compensated cutback). Given that the intonation error is affected by the action height, I'll wait until I find the optimum string height before adjusting the leading edge of the saddle. The effect is lessened in this case as I am using HT strings and have a 662mm scale instrument. Also my frets are medium height so I think the problem is less than it would be with taller frets.