Guys, I have seen so many folks use God knows what to cut fret slots. Hacksaw blades, coping saw blades, knives. Well, if you want to cut them right, you have to use a decent saw. First, let me say that if you use Stewart MacDonald fretwire (or any fretwire that is .024"tang), the BEST tool is their fretsaw. Make no mistake, that is the tool to use. BUT if you are not inclined to buy a $30 saw, try this saw:
Japanese Flush Cut Saw
. No, its not a fret saw and NO its not the StewMac version. But it is the closest thing I have ever seen to the Stew Mac saw. Stew Mac fretwire has a tang that is .024" and this saw is rated at .023". Not exact, but damn close. I even built a jig that might come in handy, plus I added a stop bar to the saw like the StewMac saw.