The problem is that once the frets are in your ability to change the fret board is gone.The above is very wrong and untrue. I hate how those of little experience speak things as fact. Speak, but add "I -think- the problem is....". Don't state as fact. That just de-rails things.
fact:
There is a great opportunity to straighten the fretboard after the frets are in, and before it is glued to the neck, than by fretting after the fact. When you fret a completed instrument, what have you to control the neck bow? Truss rod, and maybe fret tang size. None of you, 'cept David, can likely do compression fretting. So y'all rely on the rod. You fret, then tweak and tweak that rod, hoping it will adjust the relief evenly across the whole neck. My experience is that few rods ever do so. So you add Cf in the neck, you make laminated necks to make them stiffer. 2 way rods....
meanwhile i use Spanish cedar on guitars that will live their entire life with Mediums, and use nothing but a aluminum Gotoh Martin style rod. Single action, please and thank yo. Or I use non at all.
Press the frets into a dead flat board of the proper shape, tweak it to make it dead flat. You can bend it backward to take out the bow. You can press with little blocks between sections. You can control it every which way you wish! Don't tell me you don't have any control left after you fret, fercryingoutloud. It's just the beginning! When I'm done(and it isn't hard at all...), I have a dead flat fretboard that is completely fretted, fret ends milled and shaped. I can now be assured that gluing this flat fretboard to a flat neck with epoxy that won't induce any kind of bow, using a heavy aluminum caul(thanks Bob!), sitting on a dead flat, machined cast iron plate(old tools! seek out old tools at the dump). It's flat from beginning to end.
I didn't always have this system, and many of my older works aren't up to par, but today, I'll challenge anyone's fretwork and setup. My personal mandolin, with a solid, non-adjustable neck, runs with an action in the mid .020's at the 12th fret. fretted before going onto the instrument, and without the benefit of a adjustable truss rod. In fact, none of my own instruments have adjustable rods. I use those in the ones I sell to appease the buyer.
Bottom line, it can work. No, it won't magically make you a great fretter and setup man on the first try. It's a system. You either commit to it, or not.
