Another option to the sets mentioned by Jerry IF YOU USE THEM FREQUENTLY (read "expensive").
There is a set of drill bits designed for the furnace repair industry called "orifice bits". Typically, these range from a number 40 (0.073) to a number 80 (0.0135) which cover virtually all sizes necessary in most carburetor work other than carburetors with metering rods. Each of these drill bits has a "handle" (the drill bit is pressed into a roughly 2 inch length of 1/4 inch hex brass); so no pin vise is necessary; these may be used as is.
I know the above description sounds vague, but if interested, use your favorite search engine to see a picture.
I wore out several pin vises before my Dad, who used to work with natural gas, mentioned the orifice drills to me.
Whichever way you go, DON'T BUY THE CHEAPEST SET YOU CAN FIND. Carburetor jets are produced from a brass that is comparatively hard to minimize erosion from the gasoline. The cheap bits will simply not cut the brass.
Jon
