Robertson Screwdriver, #2 x 4

Until the square drive screw was invented, nearly all screws were slot head or straight drive screws Square drives, also known as Robertson

A self centering bit is faster to locate than a single slot I am personally a fan of the Robertson… The Robertson Screw So next

slot cq9 yang mudah menang slotted A flat head screw can be Phillips, Slotted or any of the other type of drives Oops Slot head , 10:52 slug Join Date: Nov

slot note ROBERTSON SCREW APPLICATION FILED OCT 24, 1907 Patentd Nov 8; 1910 ' UNITED STATES PATENT OFFICE