redmarshall

Thanks for the replies! It is surprising to me that this is such a gray area. Hit and miss it seems even for long time professional luthiers. I have seen the StewMac neck jigs and understand the principle at work but I am not sold that this will result in the neck being left with the correct arc once the strings are retentioned because of the variances in the taper and composition of the wood. Even though the frets will be level, the neck will form whatever compound curves it wants once the strings are back on. Hit and miss. I understand that action and relief is a personal preference but the curve of the neck should be a certain determinable curve based in science and math, not guesswork. Maybe a caternary is the correct solution? I still have not been able to find a solution even after googling... I am disappointed so many professional luthiers are willing to accept this type of hit and miss methodology to their work. Surely there must be a better way....

Thank you. I am aware that this is pretty much the standard way of doing this but I am still confused as to whether this leaves the correct curve on the neck? I have been playing for decades and have a small arsenal of guitars all of which I have set up more or less along the same method as you describe. Set the truss rod for a level neck and then level the frets with a fret file or radius block. Sure no problem . Then restring and set the truss rod for a few thou clearance. Pretty standard stuff. But I see this new device, the Katana which level the frets with the strings on. Now by the looks of it, it will curve in a perfect arc when the knob is tightened, which should leave a perfect arc on the neck. But do we want a perfect arc. I am sure that tightening a guitar truss rod will not leave a perfect arc but accentuate the arc towards the nut and hardly at all past the 12th fret. In other words, a parabola. But is this what we want or do we want a perfect arc? Is there a book or webpage with guitar physics thoroughly explained? Thanks!

I am new at this but a long time player now looking to invest in some tools and set up shop. So I see that there are various methods to leveling frets but what I'd like to know is what is the correct curve for a neck? Some neck guages measure at the 5th fret some around the 7th, while others use a staight edge and feeler gauges but this all leaves me confused. Should the neck have a perfect arc to it or should it be more parabolic towards the nut? I see products like the Katana for fret levelling and although info is limited on the device, it looks like it bows evenly when the nob is tightened. So this should leave a perfect arc on the neck but is this correct? Seems to me all my guitars seem to have more curve down at the nut than further up the neck so obviously this is not a perfect arc but more of a parabola but which right? Has anyone ever studied guitar string motion?