Will try to put up a pictorial timeline for the levers used, but that will take some time! it's not easy though! anyway B4's seem to have lagged behind with updates on 16H's, and the cutoff date for solid lever pivots are more 1941 then 1940, and even then it was in 2 or 3 stage versions, starting with the pivot bracket, from folded steel with solid lever blades, going to full folded steel ones in 1943-ish. This was presumably done as the cast pivot brackets damaged/broke much much more in use then the lever blades, so there was a large stock still from those, and had to be used up first.
Interesting subject, and what research I had done before seems to indicate late (1942) Big 4's had the folded steel pivots and solid (steel) blades.
The small hex adv./ret. levers were not introduced till 1943/44 as far as I can see, they preceded the ones used for the 7/8" bars in 1944/1945, where the levers were all folded steel, but a different version Doherty again!
Then there is the "C" clamps for the levers that went from solid brass to solid steel (all matt chrome plated) to the folded steel strip version all cad plated.
Cheers,
Lex
email (option): welbike@welbXXX.net (think about this!)
