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BSA Owners' Club Workshop Discussions

The BSA Workshop => Twins => Topic started by: cornishbob on 02 Jun, 2024, 07:18

Title: smiths speedo nuts
Post by: cornishbob on 02 Jun, 2024, 07:18
anybody know what size the mounting bolt threads are? they look 3/16" but are they bscy unc or what?
Title: Re: smiths speedo nuts
Post by: Bicycle repair man on 02 Jun, 2024, 07:49
2BA thread size. Same TPI as 3/16 BSF and cycle thread but different thread angle. 
Title: Re: smiths speedo nuts
Post by: cornishbob on 02 Jun, 2024, 10:32
thankyou my good man. theres so many different thread sizes and pitches and things it makes you swoon
Title: Re: smiths speedo nuts
Post by: V500 on 02 Jun, 2024, 13:00
They're a bit of an oddball thread in that Smiths used a lot of Metric threads, so sometimes an M6 nut will fit and other times it's 0BA. Must admit I've never seen 2BA on the mounting studs though.
Title: Re: smiths speedo nuts
Post by: Bicycle repair man on 02 Jun, 2024, 14:31
My gray faced magnetic are 2BA. My Chronometric ones are 0BA
Title: Re: smiths speedo nuts
Post by: cornishbob on 02 Jun, 2024, 16:41
i will let you know. ive ordered 2ba
Title: Re: smiths speedo nuts
Post by: Allan G on 02 Jun, 2024, 21:08
You should be fine with 2BA. A draw full of magnetic speedos and they are all 2BA.
Title: Re: smiths speedo nuts
Post by: V500 on 04 Jun, 2024, 09:12
My apologies then. I thought (obviously wrongly) that the OP was referring to a Chrono speedo.
Title: Re: smiths speedo nuts
Post by: cornishbob on 05 Jun, 2024, 18:35
chrono speedo. definately not 2BA
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