Bob and Mike, Thank you for your replies. I did try one piece and, as expected, it splintered the corner as I exited the end grain. Since this was a practice piece, I moved the template in a bit and continued to route the end grains. A rather slow pass seemed to do the trick. I then used a round over bit, raised enough to leave a 32nd of an inch groove at the bottom of the bit. There were no end grain problems with this bit.
The next phase will to use stop blocks, and plunge cut two slots for the playing cards. The rear slot will have a slight angle, the front slot will angle more so the viewer can see the cards in the rear slot. Now I need to read up on how to get that angle, maybe a very thin shim for the back slot and a thicker one for the front slot.
Dennis in Boise