A Sta Rite #U11-200P is the 1/2 union(female side) that connects to the Dyna-Glas pump and also the filter housing.  The pump manual says that male threaded portion is a 3-1/4" Buttress Thread.  I'm trying to find a male plastic fitting with 3-1/4# Buttress threads so I can make an adapter to screw into the female half.  Can anyone give me a source and part number?  Thanks for your help.