My friend Jonathan Chalfant has this steady gig with a friend who makes composting toilets. They are a plastic roto-molded affair used in boats and campers. As fabricator Jon is called upon to manufacture the stainless steel hardware and on occasion modify the molds used in the roto-molding process. Modifications were once again deemed necessary so a bit of precision machining was required on one of the tank molds.
http://airheadtoilet.com ) made by the mold Jon had to modify. The mold we were working on was the front liquids tank. The little round viewing port needed to be lowered a half inch for better clearance of the top radius.