A lot of people call a bolt / nut 'Whitworth' when in fact they are BSF. Most spanners (wrenches) and sockets post 1960 are marked with both Whitworth and BSF sizes on each tool. Basically the threads are different and the 'size' refers to the shank size but the heads are the same. The tools will be marked for example 'W' and 'BS'. For instance, a spanner marked 5/16”BS (for BSF) will generally be marked 1/4”W (for Whitworth) as well No Whitworth sizes were used on Minors they were all BSF or BA. The exception being the engines post the first side valvers which were all UNF / UNC which are familiar in the USA.
![[Ep4] Minor Traveller Restoration - final assembly begins](/img/n.gif)
A lot of people call a bolt / nut 'Whitworth' when in fact they are BSF. Most spanners (wrenches) and sockets post 1960 are marked with both Whitworth and BSF sizes on each tool. Basically the threads are different and the 'size' refers to the shank size but the heads are the same. The tools will be marked for example 'W' and 'BS'. For instance, a spanner marked 5/16”BS (for BSF) will generally be marked 1/4”W (for Whitworth) as well
No Whitworth sizes were used on Minors they were all BSF or BA. The exception being the engines post the first side valvers which were all UNF / UNC which are familiar in the USA.