You're right. The correct dimensions are 11 3/4 x 6 1/2. I had recieved the termite tool 3 days before the request for the urn came in. It was a life saver. I never would have finished on time without it. I had to work the hollowing from both ends then install the caps. I used your idea with the PVC cleanout for the threads. His wife and sons were very happy with it.
