This is my first effort to make a box where the top screws off from the bottom.  I used plastic at the join glued to the top and the bottom to cut the groves.  Learning experience and it works.  The hat is from the Bay Area Wood turners which I am a member of.  We meet in Pleasant Hill once a month.  Terrific group of over 140 wood turners.  We get expert wood turners from the U.S.A. and world to make presentations to us showing various techniques.