A friend with Solidworks has offered to draw up a new burner, so I thought I would post a few pictures of the old burner to help with dimensions. Here’s a picture of the uncleaned burner with about two inches of ash build up in the bottom of the burner.
The tape measure in this view gives a little help with size. Originally the back flap was designed to help with air flow a sort of chimney effect, however this was of limited help and probably helped trap ash as do the high sides.
The larger holes are 1/2″ and the ash still doesn’t fall through unless stirred.