This is a small point but there is no such thread as British Standard Coarse. The original standardised engineering thread was Whitworth. When a need for a finer thread was perceived, it was called British Standard Fine. The coarser thread was then re-named British Standard Whitworth or BSW. The only BSC I have among my tools are on taps for cycle threads which should really have CEI on them. I have simplified this a bit as it is only peripherally related to classic lightweights. At least post war bikes are reasonably standardised. Try finding a headset for a pre-WW2 Rudge if you want a problem. Re my previous message regarding the Curry Landskiff, on re-reading the passage in Curry's book, I think that it may have been powered by 'rowing' perhaps with a sliding seat also contributing something. Come on, you recumbent enthusiasts! You must have heard of it. Stuart (pedantry is meat and drink to me) Tallack in Sussex.
"When a man gives himself up to the government of a ruling passion, - or, in other words, when his Hobby-Horse grows headstrong, - farewel cool reason and fair discretion !" Lawrence Sterne