This cottonwood bowl is 7" x 7". It was turned to about 5/8" and the rim undercut to a thickness of 1/4". I sectioned it off into eight equal slices and cut the separations to a depth of 1/4". This, of course, gives a wall thickness of 3/8" where the slices are separated. Each slice was carved to a concave shape using a variety of palm tools and Typhoon burrs in a Foredom and hand held Dremel rotary tools. The result is that this bowl is a little on the weighty side, just a little more than I like in this case, but I didn't want to take any chance on penetrating the wall when I separated the sections. I only sanded it to 320 grit (all hand sanding, naturally, as the sanding could not be accomplished with the lathe spinning) and finished off with several (can't remember how many) coats of natural Deft danish oil.