In a pinch, you can use a 5/64 drill bit. The hole will be a little smaller than .089 (.078125 to be exact) so it's about 10 - thousandths undersize (or about the thickness of 5 human hairs) but if you just wiggle the drill a little that will be gone in no time. In fact, just drilling the hole usually makes it 5 thousandths oversize anyway. (Can you tell I used to be a machinist?)

Just go real easy with the tap, and if possible, use one with only 2 flutes