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Old August 5, 2011, 07:28 AM   #17
SDC
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Join Date: January 23, 2001
Location: People's Republic of Kanada
Posts: 1,629
These have the appearance of being made on modern machinery, with fully-formed cut threads along the complete shank; the machinery to do that didn't exist until relatively recently, and before that, mass-produced screws and bolts were usually made by either threading and heading round stock, or by rolling.
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