This nut fits on the bevel end of the camshaft, and is lipped, to hold the special 'half moon' bevel pin (our Item 0065), and our nuts follow the original Norton design - the lip dimensions ensuring the pin is held captive and not rotate.
These nuts are CNC machinied in high tensile steel, and of course - the Hex is milled to the original Whitworth spanner size dimensions (hence why they are not the cheapest of nuts - requiring milling op).
Note: This nut is 'Right Hand' (i.e. normal) thread, while the camshaft nut on the other end is a LH nut. This nut is often used by SOHC owners to help set valve timing and rotating engine, so it is worth ensuring it is in as good a condition as possible - if your original has a worn thread or worn hex faces, it is often worth replacing.
As well as fitting all SOHC engines (Arthur Carrol type) it also fits most DOHC engines - including all the long stroke type). Email for dimensions if you have a DOHC shortstroke engine and want to make sure).