solbt

Here you can take a deeper dive into details.

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.

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I’ll add few more here, in case someone wants to know how some of the screw heads mentioned look like.

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.

Where you live, Combination-Head Screws are widely used?

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?