smiths speedo nuts

[cornishbob]

anybody know what size the mounting bolt threads are? they look 3/16" but are they bscy unc or what?

[Bicycle repair man]

2BA thread size. Same TPI as 3/16 BSF and cycle thread but different thread angle. 

[cornishbob]

thankyou my good man. theres so many different thread sizes and pitches and things it makes you swoon

[V500]

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.

[Bicycle repair man]

My gray faced magnetic are 2BA. My Chronometric ones are 0BA

[cornishbob]

i will let you know. ive ordered 2ba

[Allan G]

You should be fine with 2BA. A draw full of magnetic speedos and they are all 2BA.

[V500]

My apologies then. I thought (obviously wrongly) that the OP was referring to a Chrono speedo.

[cornishbob]

chrono speedo. definately not 2BA