ROBERTSON Machine Screw 8-32 X 78 Truss Head Combination

Jonard's Robertson Screwdrivers are made with an S2 steel shank with a chrome finish for exceptional strength and long life Our Robertson Screwdrivers

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

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

slot milling diagram Robertson Square Drive Screwdriver #2 Head Red Handle This red handle Robertson® size scrulox screwlux square drive screwdriver suits screw gauges 8