Had a brewer who wanted to tri-clover his valve's on his kegs plus beable to have threads inside the keg for pick-up's
This is what I came up with. Its a full coupler with the threads remove from on the Tri end for easy cleaning. The 1 1/2 is tig welded inside and outside so there is cracks for things to hide. The keg side of the coupler is turned down o/s to one inch for easy of drilling a 1 inch hole.