Step 46: Square Recess
[[br]]Only Robertson Inc. makes Robertson® screws and drivers, the others are generically called Square Drive and are made by several manufacturers and brands since the patents have expired on the Robertson. The Square Drive head is an American clone of the Canadian Robertson® that has a square recess but not tapered and has very sharp corners. Likely this difference was to avoid patent infringements. The patented Robertson® driver has a slight taper, and slightly rounded corners. See Robertson® Recess.
Two methods of fabrication are the machined one piece and the two-piece is a forged steel tip press fitted into a regular steel tip holder part. Several companies each with their own select brand name produce square Drive.
Due to the lack of taper, the hole must be oversize relative to the screwdriver, and is much more likely to camout than the Robertson®. It is infuriating that Home Depot® and the tool companies like Bosch® and Dewalt® bring square drive bits into Canada that almost fit Robertson® screws and are marketed as equal and are unmarked. For any Canadian readers that want bits that work, try to buy the bits that are color-coded red, green, black as well check the engraving is an R on the bit. Don't trust the cheaper bulk packs. Never trust a Robertson that says "Made in America"; it is likely a Square Drive. A "fresh" American Square drive driver with a "real" Robertson® screw head sticks so tightly that it can take a significant yank to get them disengaged. This is advertised as a selling point of the American Square drivers here in Canada. Unfortunately, if you have to pop out the driver, it usually means you're damaging the tool and is more difficult to use from then on. Real Robertson® drivers do not suffer from this with Robertson® screws. So, while they don't stick quite so tightly, the drivers really do last a long time, and they're just as good at keeping grip under power. Bit sizes come in only four sizes and application and are rarely color-coded.[[br]]