Thanx, yeah, I have definately thought about the vehicle concern. I'll plow here, since its my parents house.
Yes, they are a 6" mortise and tennon joint, the full size of the rail (not cut down). I had no idea thats what I was doing when I started this (as far as the technical term).
Stone faced, shoot me a PM with any questions. I also want to know what kind of tools your using for your stone work, Im wanting to do some different things.