If you have a drill press, get yourself a big set of drills (numbered, lettered and fractional). They will come in very handy in this hobby. Find the drill that is closest to 10mm and drill out your prop. To be sure you get a good hole, level the drill press table, locate the prop hole (by chucking a smaller drill that fits the prop) and clamp the prop to the table.

If you don't have a drill press then a reamer like Fox sells is probably the best solution.