Yeah, heed Bob's warning... these are for drill press or mill work only. Carbide is strong, but very brittle. Trying to use them in a pin vise takes a whole lot of talent, as once you bend them a little off center, they will snap. And once they break off flush in plastic, good luck extracting them.
The high speed steel ones are much more forgiving, as they bend. Use these for hand work. Smallest is #80 usually though.
For smaller wire details, sharpen a piece of music wire of an appropriate diameter. My friend Vince put me on to this... he was putting .004" drop grabs (made from guitar string) on an Atlas C628. He said the Atlas plastic was great, in that a stubby, sharpened piece of the music wire, mounted in a handle or pin vise, could be used to pierce the plastic and make a hole. No drilling motion is even necessary, just align and shove it through. Perfect size holes, and it sounded like there wasn't really even a need to glue. Just push the drop grabs into the newly pierced holes, and friction held them in place. Once the layer of paint was on, they weren't going anywhere.
