I mentioned that the vice I installed came with screws that use Robertson heads (see the picture below).I had not come across these before and while looking into them I came across an excellent article describing the baffling array of screw types available, including a potted history and a summary of the pros/cons of the designs.
Here is what you need to know about the chequered history of the Robertson screw:
The first known use of a metal screw was in 1513, and the design did not change much until the start of the 20th century when rapid developments in manufacturing and increasing pressure on costs spawned the development of a number of innovations in screw design.
The Robertson screw has a square hole and is designed for use with a slightly tapered square screwdriver bit. It was invented by Peter Robertson in 1908 and a US patent was granted in 1909 (US1003657)
The design is self centring and the slight taper on the bit means that the screw grips the screwdriver making it possible to use with one hand. The snug fit also reduces the chance of”cam-out” where the the screwdriver leaves the screw under torque, risking damage to the screw and the screwdriver.
Henry Ford realized that the design could save him a lot of time and money on his assembly lines and used them for Model A and Model T production in Canada. He was interested to use them on his America production lines too, but changed his mind when Robertson refused to sell him exclusive rights, adopting Philips screws instead. It seems that Robertson was extremely protective of his intellectual property, having struck up a deal with a distributor in the UK that went sour leaving the UK firm with manufacturing rights. Eventually Robertson was able to buy back his IP, at great cost, but after that he refused to grant any further license outside of Canada. This allowed the inferior Philips design to gain a stronghold in the US and elsewhere and the rest, as they say, is history.
Robertson screws account for 85% of all screws sold in Canada and close to zero everywhere else, a terrible missed opportunity, if ever there was one.