I noticed the same thing. It seemed the closer the growth rings the better and the more parallel the grain to the cut the better. The problem I had was that the grain on my strips ran NW to SE on some sections and NE to SW on others. So I was destined to have problems no matter which direction I milled the cove.

Ken

: Ken: I had the same problem when I started milling my strips. I noticed that
: it seemed to be a function of the direction of the grain. I'll try to
: explain, but maybe I should post a picture?

: 1) Let's say that the strip you are milling is being pushed from South to
: North on your router table.
: 2) The router bit is on the East side of the strip.
: 3) The bit rotates from North to South on the side that contacts the strip.
: 4) The wood grain of the strip is never actually completely parallel to the
: length of the strip.
: 5) In order to minimize chipping while routing a cove, the grain should be
: aligned from North-West to South East, or as near to that direction as it
: naturally runs.

: I know it sounds confusing, but draw it out. Hope that helps a litlle! When I
: made this change I didn't get any more ruined strips.

: -Charlie