UNF Bolts & Screws

UNF (Unified Fine) threaded fasteners were phased in on BSA, Norton, and Triumph motorcycles produced in the late 1960's and onwards. Used where both bolt and nut were made of steel. Also at this time most screws and bolts that threaded directly into alloy castings changed to UNC (Unified Coarse) threads for better holding power in the softer material.