Here's what I can say from bikes I know:
long "oval" slots, look a lot like Campys but with flush outer edge (no ridge), small web - late 1950s, per Marty Walsh's Helyett.
8 round holes, ~7mm and widely spaced. - very early 60s (my Sears). What I think were the first of these have the left flange of the rear all the way outboard, and were notorious spoke-poppers on the right side.
roughly triangular holes - Schwinn version, mid-60s?
harvey sachs mcLean va ++++++++++++++++ John Crump wrote: Does anyone know (OR CARE) about dating Normandy hubs, I have one pair Large flange that have round oles in em. Now I see another pair NOS yet, 40 32 Single fixed with slots in em, Did they follow Campag in the mid 50s Campay had holes in the flanges two rows of em in the early 60 they had one row of oles, them they went to slots, like the Normandy ones on Brit Ebay, anyone have an answer? Cheers John Crump OldfullofolesBrit, Parker, Co USA PS Did 40 miles on my 54ish Holland with the Normandy round ole ubs To-day