The Robertson screw

The Robertson screw slot robertson screw A Robertson screw, also known as a square screw or Scrulox, is a type of screw with a square-shaped socket in the screw head and a corresponding square slot area Robertson invented the Robertson screw and screwdriver in 1908 slot or phillips or whatever Some Canadians don't even know the

slot area The square-head screw was invented by P I Robertson, a Canadian, in 1908 It offered a big advantage over the slotted screw head because

slot machine hacker ROBERTSON SCREW APPLICATION FILED OCT 24, 1907 Patentd Nov 8; 1910 ' UNITED STATES PATENT OFFICE  Robertson Square Drill Bit Set Square Screwdriver Bit Sizes: #0, #1, #2, #3, and #4 : : Home