American /British thread size difference

[smylee grouch]

Can anyone tell me what the difference is between the US vs British thread size. American thread size nipples 1/4-28 vs. British 1/4 BSF.  What is the BSF thread number per inch? If the British 1/4 BSF was 28 threads per inch, could you use an american 1/4-28 nipple in the gun or is there something else involved here that would prevent that?    Smylee

[billd]

Not sure about BSF, but some British threads (Whitworth, I believe) are 55', SAE and ISO threads are 60'.  I should be able to find BSF in a book I have at work.

Bill

[Old Ford2]

You can force a US ( SAE thread ) into a British thred, but not British into SAE thread.
British ( Whitworth threading ) is 55 degrees.
It would be better to run a tap into the British thread first.
British BSF thread would be 1/4-26 threads per inch
Old Ford