First, find out what the hole diameter is for the prop you are using, next find out the diameter of the prop shaft. Get a new drill bit the size of the prop shaft and take it to a grind shop and have them grind a pilot on the bit the size of the hole in the new prop. Use a drill press to drill prop and if you are drilling wood props set the drill press to is highest RPM and you will get a very clean hole with no wobble.