On Sat, 02 Jun 2007 00:14:10 +0100, Frank Erskine
wrote:

Why not ½ or ¼ inch, which it really is?

It's probably illegal to call it such, under the "prevention of straight
bananas act"

However if you ever find a 6mm collet or a 6mm cutter, throw them away
before you mix them up. They'll come loose and throw themselves at you.