Any screw thread experts?

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geeman237

Original Poster:

1,247 posts

188 months

Tuesday 25th June
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I was nerding out on a copy of the Standard Triumph Hardware Catalogue and came across references to screw threads that were distinctly separated and I don't know the difference, so perhaps someone here knows.

The catalogue specified for example, 1/4" NF and 1/4 UNF as two distinct threads. I know most Triumphs of the 1960's on used UNF which is an American standard. But what is 1/4" NF or NC as a thread type, what standard is it known as? The catalogues also explicitly identified BSF, BA and Whitworth in its descriptions. I get the impression that 1/4" NF is not the same as 1/4" BSF?

This should be a link to a pdf of the catalogue. Page 4 of the catalogue shows what I mean.

https://www.google.com/url?sa=t&source=web&amp...

Anyone able to enlighten me?