What's that Lassie? You say that Greg O fell down the old
rec.crafts.metalworking mine and will die if we don't mount a rescue
by Fri, 7 May 2010 18:03:41 -0500:

It has been a few years, but like others have said, just go with a square
groove. Seems to me we would make the groove same width as the o-ring, and ...

No. The width of the groove should be equal or greater than the width
of the O-ring.
--

Dan H.
northshore MA.