Fork crown main tube clamping stud and nut, Norton short road holder, 7/16 x 20tpi reduced hex (same as originals 3/8in BSF) use on LRH to give better spanner clearance. The clamping stud is often referred to as a pinch bolt. Original part number: F11M2/643; 16187 - nut for stud x1 [ for F11M2/642; 16164 - Fork crown main tube clamping stud]
