If any one thing distinguishes Canadian home improvement from American home improvement, it is the Robertson (square socket) screw. In this segment, we took a look at the history of this famous Canadian invention and visited their head office and warehousing operation in Milton, Ontario. Wikipedia has a great comparrison of most screw types, and describes how Robertson got restrained to Canada by political and commercial reasons despite its superior qualities for a low cost production screw.
The Robertson head, the standard for all Canadian screws, is a square socket. The Philips head, the standard for all US screws, is a cross recess. To bridge the commercial gap, Robertson has now come out with the Recex, which accepts both the square and cross drivers. As with most compromises, it is useful, but not as good as the "Cling Fit" Robertson square socket -- but then again, I am a patriotic Canadian. The Pozidriv is a modification of the Philips to match the qualities of the Robertson that the screw driver will not jump out of the head but it won't hold the screw for one handed operations as is so easy with a quailty (not all brands) square socket screw.
The standard Robertson and the Pozidriv are slowly taking over all serious markets with Robertson getting into OEM manufactur and Pozidriv dominating in England. I have never figured out why but US stores still have good stocks of slotted screws for all uses -- a frustration guarantee in any project. One drawback to Robertson acception in the US is the large box store presence of cheap Chinese square socket screws that snap off because of poor manufacturer -- keeping Americans from realizing the value of the good Robertson screws.
A personal message to any of our friends to the south looking at this site -- try a well made "Cling Fit" Robertson screw, one where you can hang the screwdriver from the screw without magnets (like in the photo), and you will never go back. Hanging the screwdriver is just a gimmic, but being able to reach out with one hand and a 3" wood screw in the driver is magic.
One interesting note is that there exist no Robertson drywall screws. When applying drywall compound over the screw heads, the square socket forms an air pocket that pushes the compound forward, making a bulge. When you apply compound to a Philips head drywall screw the air escapes out one of the four channels, letting the compound fill three channels and leaving one little open pin hole. That is why we always cover screws with a double action, the first pass fills most of the head and the second pass catches that air hole. At the very end of this Drywalling video you can see the two stroke action for drywall screws.
Follow this link for how these screws are manufactured.
Follow this link for some history on this Canadian invention and its inventor, P.L Robertson from the Robertson company itself.