4" x 4" x 1/2" aluminum plate and the center marked             Using the 4 jaw chuck the center is drilled to 3/8".
 
 

                     A few thousands taken of the face.                                 A recess was bored for the shoulder of the body
                                                                                                          to fit in.

                              Completed  base                                               This is the bottom side of the base. I used a 3/8
                                                                                                      countersunk allenhead bolt for attach the body.
                                                                                                      The top of the bolt needs to be flush with the base.
                                                                                                      The bolt length was ground to achieve a tight fit
                                                                                                      while allowing the body and base to rotate freely.
 

                   Base and body. On the body there is a slight                                            Assembled
                   recess (.010")  to hold grease.
           I applied a thin layer of grease before assembling.