The Invention of the Robertson Screwdriver

Why Are Robertson Screws So New To America? - Eng-Tips slot robertson screw by Fred Scheuler In 1906 Peter Lymburner Robertson, wounded by the slippery slot of the primitive screwnail, invented the square recess slot machines symbols In 1908, Canadian Peter Robertson invented a square-head screw drive where the driver and the hole had a slight taper There had been other

slot bank bca In 1908, Canadian Peter Robertson invented a square-head screw drive where the driver and the hole had a slight taper There had been other