I guess this is one of those hubs where you either know what it’s off, or you can have hours of fun researching it. I am in the latter category. I guess it’s for a Pre-war rigid frame by the diameter of the hub.
I believed it was for a Velocette Mac. It may be, but I can’t find any evidence.
The 3 bolt holes suggest AMC / Norton.
The pretty pattern spoke holes on one side suggest Triumph.
Does anyone know for sure?
It will be sold with the speedo gear, spindle and nut.