[MrForbes]

Off the shelf solution: get a very short 1/8" npt nipple, and an 1/8" npt coupler, and put the mounting bracket between them, and screw it together. You'll have to mess around to get the spacing correct so the pipe threads tighten about the same time the bodys of the cup and coupler contact the bracket.

I can draw a sketch if you don't understand, let me know