Dummy Coupler Sergent Compatible

These are HO Scale.  You get eight Sergent Compatible type E couplers once you cut them free of the sprus.  The Sergent drawings that are in the public domain were used for the coupler.  The inside of the coupler is filled with material, they CANNOT be made operatable.  The fit between two couplers is very tight, see the screenshot of the CAD drawing.  This is how the Sergent drawings fit together.  Expect to do handfitting to make the couplers mate together.  Get a test sample for yourself before buying a boat load of these.  
Can't get the Shapeways tools to approve any plastics repeatedly so we have brass and bronze.