In the June 1967 Reporter Schwinn stated that U.S. Defense Department orders for nickel for the Viet Nam war effort forced the Schwinn factory to use cadmium instead of chrome for plating certain parts including seat posts, #7301 seat post clamps and kickstand sprags. The article also stated that Schwinn had been using cad plating for rust prevention on parts for 35 years prior to that point.
From my observations the mid-'67 change from chrome to cad for these parts applied to most of the popular electro-forged models, however fillet-brazed models continued to use chrome plated seat posts, binders and kickstands (sprags) throughout their production. Years later some of these parts reverted back to chrome on certain EF bikes, for example the Continental (and in '74 the Sprint) had continued to use chrome binders (but not posts or kickstands) but then changed back to using chrome posts and kickstands in '76 and later models.
