Were the Smiths speedos not originally made under license from Jaeger, a European firm? I understood that is why the mounting studs were metric together with the 1mm pitch thread that secures the bezel to the body.

Regards Jim

email (option): johnboywalton13@msn.com

Dennis Quinlan posted this drawing on the Smiths Chronometric Facebook Group.

It shows that by 1957 at least, the studs were 0BA but it can't show if they were metric in the early days...I suspect that pre-war (with the Jaeger drive) actually were and that the licensing agreement ended with WW2.

The 6mm stud size is pretty well identical to 0BA but I'm sure the nuts would have been imperial hex in UK. Ron

email (option): ronpier@talk21.com

I agree Ron. The dull chromed Norton nuts had imperial hex. without any doubt. The case studs are too crudely rolled to accurately measure.

There is a difference between the M6 and 0BA thread angle, but as you say Rik. To crude to worry about. Ron

email (option): ronpier@talk21.com

Thanks all

Will check when at Newley marsh where fittings & screws are plentiful

Br

Jo’b

email (option): jonnyob1@googlemail.com