I wonder why this kind of screws are not more popular? Is it really that much harder to produce them or there is some other reason for not being used everywhere? You can use them either with flathead or Phillips head screwdriver, looks like win-win solution?
It’s juts a way to strip the same screw head twice
Good comment to add some more info here. I wasn’t trying to claim superiority of this screw. As an afterthought I figured that adding that additional cut for flathead screwdriver compatibility, could have been helpful with stripped heads recovery. I’m gonna try to buy some of those canadians screws, looks hard to strip.
you mean Robertson, yeah, they are the best.
Robertson’s efficient manufacturing technique using cold forming for the screw’s head is what made the idea a commercial success, so it looks like Canadian popularized it, even though it was patented by US earlier but not commercially manufactured.
P. L. Robertson invented the Robertson screw and screwdriver in 1906 and received the Canadian patent in 1907 (CA103387, U.S. patent CA103387A) and US patent in 1911 (U.S. patent 1,003,657) for a manufacturing machine. The cold forming was a separate patent.
Roberston refused to license to the US and Henry Ford because Ford was being a dick.
rightly so!!! those slippery ass mf-er’s have cut/bruised my hands more times than i care to remember.