One of the first things you will notice when you look at the equipment in your favorite brewpub is that it is constructed of stainless steel, not plastic. Next, if you look closer, you will not find any blind threaded connections: clover clamps rule.
So, here is how to convert your stainless Chugger to sanitary fittings.
First: Get two 1.5 in clover caps, and drill an accurate .75 in hole in the middle. You are going to tap these holes with a ½ in pipe tap, so they should accurate and centered. I have an engine lathe, which makes the job easy. I drill the holes with a carbide hole cutter. If you look up the tap drill size, you will find 45/64, but since they will be welded, the threads only serve to hold the cap in place; the oversize hole makes the job easier. Pic 1 shows the parts ready for assembly.
Next, screw the caps onto the pump head so that they are about 1/8 in from the mating face of the cap. This is shown in Pic 2.
I simply fuse weld what is essentially the resulting outside corner joint (seems confusing at first, but think about it) using the pulsed tig process to minimize heat input. The result is shown in Pic 3.
This completes the construction. You’re ready for better beer.
If you use threaded connections and don’t disassemble them completely after each brew, you will be amazed at the amount of moldy gunk that accumulates over time in the pockets, even if you flush the system well.