On Mon, 7 Aug 2017 05:02:56 -0700 (PDT),
wrote:

Sorry friend. Triumphs, just like American vehicles, used Unified threads back in the sixties. If you are in the spares business you would know that.
In the very early sixties there were BSF and whitworth,and UNC and
UNF as any British car mechanic would know. In the seventies the Brits
switched (slowly) to metric.