It doesn't matter- as long as it is, like Hillbilly said, legal. Getting the "ferrule" (usually the wood) as close to the tip as you can seems to improve the funciton. Something about an inch so away- and no more than two. I made my last ones 1 1/4" wide by 2 1/2" long, but that was to get the most point out of the piece of metal I was using. Thicker the metal fartehr away from the tip you can be.