ok bear with me here. go out and buy 2 stanless mixing bowls of the size you are looking for. take one bowl and find the center of the bottom and drill a hole and put a stanless bolt through and put a lock nut on the out side (bottom) of the bowl. take the other bowl and cut the flat bottom out of it. then you can join the 2 bowls ( ) top to top and clamp or bolt them together if your carefull and take tyour time you should get a pretty good seal. you could then use a power drill and put the bolt end in the chuck mount or clamp the drill and do your thing. i hope that will at least get you in the right direction.