I am currently building a strat from scratch. the body is done, and now im at the point where i need to make the fretboard. I have some Stewmac fretwire with a .023" tang. Now i could just go and buy a fretsaw from their website for like an arm and a leg, or i could use a flush cut pull saw from Lowe's that I found for $10. The kerf on the saw, though is .020". Does anyone think that this is too thin? Maybe I could do some beveling to fit it in perhaps? Or is .003" really going to matter that much to where I would have to sell my first born for a fancy Japanese fret saw?
.020 is way too narrow. It will be very hard to get the frets in the slot and it when you do it will cause the neck to back bow.
So what is the optimum kerf then?
.023, that is why their fret saws are that kerf.
Do yourself a favor and glue those frets in (Titebond should do) as well as press-fitting. Fill that tang cavity with glue so that you get a solid connection between fret and fretboard.
Another hint, based on hard-won experience. Make sure that the fret are bent to a tiny bit more curvature than the board, so that the fret ends don't have a tendency to pop up. Titebond or PVA works well, it acts as a lubricant when installing the frets.