The drive side crank on my Fothergill is marked CONSTRICTOR while the non-drive side is marked BSA (with the classic BSA pile of rifles logo). Both made by BSA, they appear to be a matched set; 6 1/2" arms with the same profile, same deep flutes on both sides. The chain ring is only marked 46. This is a typical crank on higher end English bikes of the 30's-40's. It has a five pointed star like a Stronglight, but it's a very different design; note the five pentagons.



The Williams 1200 was their top of the line model, very thin arms, forged spider. This is a lighter crank than the Constrictor above, but I'm not currently using it because the arms are 6 3/4" which is a bit long for my taste. Arms fluted on only one side.

It has the same bolt circle as most continental 3-arm cranks, such as this Magistroni. But the Magistroni is inexplicably heavier (and it's not just the extra ring)



My oldest cotterless crank is this Stronglight 57, from about 1958-9. The design is pretty similar to the Stronglight 49D:



But lately I've become fond of the SR Custom 3, made for a short while in the 1970's.

It's "melt forged" which is a pretty cheap manufacturing method, and I think results in a less than perfect finish, but it's well designed and the spider is small enough to take a 27t ring. Until recently the 86 mm bcd rings were unique, but now FSA makes a line of cranks using this same bolt pattern, so a limited range of replacement rings is available. The inner ring shown here is an FSA stainless steel one. I think of it as the cheapskate's Rene Herse crank. Speaking of which, someone has to post one of those, but it won't be me, since I don't own one. What about it, [MENTION=381793]gugie[/MENTION]?