Shop › RRBIBNUT - Rolls Royce Bib & Nut Image 1 of 1 RRBIBNUT - Rolls Royce Bib & Nut £14.00 18 tpi 9/16 dia. bib and nuts for taps. To solder on 5/16 pipe. Quantity: Add To Cart Added! 18 tpi 9/16 dia. bib and nuts for taps. To solder on 5/16 pipe.