Primarily Petroliana Shop Talk Forums Shop Talk Petroliana Forums General Petroliana Discussion What does this fit and used for

Have had this for awhile, but do not know its name. Looked up the numbers on google and came up with nothing. Goes from 3/4" on the back side to 3/4" in the center on the front and (4) 1/2" threaded holes in the front. Thought it was maybe for some station light or something.