Screw dating

We share our reference material free of charge and work hard to make it accurate, but as with any research, mistakes can be made.We are not responsible for the use you make of the information here or the honest mistakes that may occur from time to time.In 1798, American David Wilkinson also invented machinery for the mass production of threaded metal screws. Twenty-eight years before Henry Phillips patented his Phillips head screws, which are also square-drive screws.In 1908, square-drive screws were invented by Canadian P. The Robertson screw is considered the "first recess-drive type fastener practical for production usage." The design became a North American standard, as published in the sixth edition of Industrial Fasteners Institute Metric and Inch Standards.They needed screws that could take greater torque and could provide tighter fastenings.The Phillips head screw was compatible with the automated screwdrivers used in an assembly line.

She specialized in writing about inventors and inventions, in particular. A screw is any shaft with a corkscrew-shaped groove formed on its surface. A screwdriver is a tool for driving (turning) screws; screwdrivers have a tip that fits into the head of a screw.

Vintage jewelry findings of the 50s, including safety catches, pin stems and joints, ear wires and nuts. Exclusively Wholesale, 1950 Vintage 1950s jewelry findings including guard chains and ring guards.

Pin stems, screw-back earrings findings, safety and plain catches. Dual ring guards, child's ring chains, earrings guards, safety chains, cord bracelet guard chains, Benj. Exclusively Wholesale, 1950 shown here was patented in about 1894, though these earrings originally had a different style back for pierced ears.

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This page and associated sub-pages allows a user to run an American produced utilitarian bottle or a significantly sized bottle fragment through a series of questions based primarily on diagnostic physical, manufacturing related characteristics or features to determine the approximate manufacturing age range of the item.

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