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Well, not knowing anyhting about the cycle in question.....
In general old British vehicles were assembled with BSW (British Standard
Whitworth) and BSF (British Standard Fine) threaded components.
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Course
The course thread (BSW) is very similar to NC / UNC, except that the angle
of the thread is 60o not 55o (this is from memory - don't quote me) so a
BSW nut will go on to a UNC thread, but not the other way round.
Depending on how keen on originality you are you can just run a UNC die
down the BSW thread, or use a BSW tap to take out an ordinary UNC nut to
fit it.
Fine
The fine thread (BSF) has some similarities to NF / UNF, but around the
sizes we use most often the TPI (threads per inch) count is different, so
a UNF nut will do you no good at all. Solution here is to buy BSF nuts
from a dealer that restores old British cars or the like.
Tapered
never looked at the BSP (British Standard Pipe) threads in detail.
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It gets more complex as you get closer to the present day, with later
British vehicles assembled with UNF (for NATO compatibility) and I assume
the modern ones are done with those horrible metric threads.
Of course the Americans got their own back by making us all those
Carryalls with 12 guage NC screws in them and then making the size
obselete.
Gordon
This archive was generated by hypermail 2b29 : Mon Feb 21 2000 - 18:15:05 PST