Hi all,
I made my wooden ash donuts from the dementions of Dale Frolander's wood pipe's of 1 1/4" outside dia. with a 7/8" inside dia. hole. I also used a 7/8" fostner drill bit for the hole but I ground the outside 1 1/4" dia. on a disc sander. I will put a 1 1/4" hole in the bow and stern with a hole saw drill.

John