To start I had purchased a chugger pump with a stainless steel head. First thing I did when I got it was take it apart. Then drilled holes and tapped a couple tri-clamp caps to thread onto the pump head.
Weld and grind.
Then polish and sand.
And finally reassemble.
They actually make Triclamp fittings that would have simply screwed on the ends of the pump. I would probably go that route next time. I just wanted something a little more permanent with no exposed threads to the wort for any transfers this pump might be used for.