Another note that might bring smiles to a few of you. Drillium and the Schwinn Town & Country Tandem.
We bought ours, a funny-looking creature, about 1970. The old Veeder cyclometer had a thousand miles or so on it -- plus 3 stripes painted on it. We were able to find out more about it. Had belonged to Bill and Edith Lovely, who ran a typewriter shop in E. Providence, RI. Among other things, they did a double century on it in < 13 hr -- when he was 61 and she was 59. In hilly New England, with a 3-speed derailleur.
One odd feature was that the drillium technique had been liberally applied to the (steel) brake levers, the excess bits of metal in the "A,S, & C O" (Arnold, Schwinn, & Co) chainrings had been filed off, etc. Even the reaction arm on the hub brake had been drilled -- and then rebuilt when it started collapsing.
A few years later, I needed to strip it for repainting, and was messing with the little propane torch. suddenly, from under the paint, there were drips. Schwinn had "wiped" the fillet-brazed joints with lead to make them smooth, instead of filing.... So much for all the drillium. If any one needs "enlightened" Schwiin cottered cranks, I gave them to Larry Black years ago -- but kept a couple of the thick-centered bb spindles.