For those who don't know, a tap is a hardened piece of metal that cuts threads into just about anything that's made.
Most drills are hard, but have nothing, in the way of hardness, compared with a tap.
On the other hand, a tap is so hard that it's brittle. Bend it a little and it breaks. Didn't use oil, it breaks. The tip bottoms out (hits the bottom of a hole), it breaks. There's more, but you get the point.
This video is fascinating to me, cause I've broken many a tap or drill bit (including carbide bits). I've always gotten them out, but this guy gets paid better.
Jerry's Broken Drill & Tap
[youtube]http://www.youtube.com/watch?v=YbeKxFBZrF8[/youtube]