Canadians: square slot screws?

Canadians: square slot screws? slot robertson screw 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 highlander Competitive price screw cap, 2 Inch Screwdriver Insert Bits single head #2 Square Robertson 8pcs

slot highlander In addition to its superior grip, it is more versatile than the Slotted and Phillips drive Square Drive square drive screw or robertson drive

slot dolar138 Truss Head : low profile semi-elliptical top with flat bearing surface Combination Drive with Original Robertson® square and flatslot drive It is recommend Take your most basic single slot screw; hold its screwdriver in a vertical position and fit the screw on top of the driver blade It will