On Thu, 28 Feb 2008 20:45:21 -0600, with neither quill nor qualm,
"David Courtney" quickly quoth:

I use a 15mm box-end wrench to remove the drain plug on my '00
Silverado... for whatever it's worth. It does seem to have a "taper"... not
sure how they came up with that idea?

It being a Chebby, that question is self-explanatory.

--
An idealist believes the short run doesn't count. A cynic believes
the long run doesn't matter. A realist believes that what is done
or left undone in the short run determines the long run.
-- Sydney J. Harris