On 2012-10-09, Jon Elson wrote:
a friend wrote:


according to Feynman's book, these were padlocks, presumably the early
Sargent and Greenleaf type - the later ones had some anti-tamper
features but the earlier ones could be felt out, at least for a few
numbers, limiting what you had to try. go to a surplus store and buy a
bag of these locks, they are deprecated now.

Master padlocks are easy. But, I am SURE he was referring to
secure file cabinets and safes at Los Alamos during the Manhattan project.

Well ... I have seen file cabinets made into sorta security ones
(assuming that you don't cut the sheet metal to get in) by a vertical
bar through the drawer handles and into a welded ring at the bottom, and
bent, flattened, slotted for a hasp, and secured with the S&G
combination padlocks -- those had numbers up to 50 on the dials, and
were setable like the built-in safe combination locks from the same
company. Of course, a lot fewer combinations possible. 125,000
assuming that all possible numbers could be used. A mere 4,629 if any
number within +/- 1 from the nominal number would work.

These were normally used for FOUO (For Official Use Only), not
really classified stuff. :-)

Enjoy,
DoN.

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