Is there an actual reason for why there is cross-shaped, flat-headed, and even triangle shapes in screws and their matching screwdrivers?
Why are they not all just a universal type?
Bonus question: why are some called Phillips (cant remember if its the flat or cross shapes ones)
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The same reason there are different sex positions. To screw different ways!
I’ll see myself out
patent issues and different applications… a long story actually but there’s a nice wikipedia article on the subject.. (who reads wikipedia articles on screws? me!).
flathead is an ancient design for manual use but not really good for machine drilling because it is hard to center.
philips was designed for machine use, back in the day when machines had no torgue control, so it is designed so that the srewdrivers bounces off the screw when it is tight enough. this is kinda the annoying part of philips screws but actually designed that way.
a guy in canada, Robertson patented a square hole but did not want to sell the patent. So then somebody just invented hex hole and only canadians use square holes.
then somebody wanted that people stop opening and fixing their machines themselves and invented some other form of screwdriver like the triangle etc. but then somebody started selling those screwdrivers too and they needed to invent a different type.
and so on.
CAUTION: this is an overly simplified version of the story.
Henry Phillips patented the screw…as for why there are so many, my guess would be people trying new things. The flat blade has issues of course so they added a cross for extra surface area, then of course the hex came along with even more leverage. Manufacturing techniques allows the creation of the posidrive and torx. Security bits made things harder for people to remove.
There’s videos on the various origins. Phillips heads don’t get the driver (screw driver) stuck easily.
Slotted screws are a pita but cheaper to manufacture (I think used to be anyway).
This is all on YouTube.
Flatheads play nice with hand-driving in some situations in a way that Philips heads don’t, and some people say they look nice. Philips heads are useful if you actually want your driver to cam out at a certain point, and cost a little less than the better designs.
Robertson and Torx drives are a higher quality solution, especially for small screws, though they’re roughly equal to each other. Allen wrenches are pretty handy in some ways but I do think they’re just a worse Torx drive. Hex head bolts are good for high torque tightening, and don’t have a slot that can get filled with grit.
Then there are a bunch of screw heads that exist specifically to be obscure so the screws are hard to remove.
Different screw heads have different properties. The key ones are maximum torque and ease of removal.
Different styles and sizes of screw head have different maximum torques – a big ol’ 220mm wood screw will need more torque to drive it, so generally needs a bigger head with more contact area. Different bits are better suited to different heads. They have pretty large tolerances so are kind of interchangeable, but not entirely.
If you want a screw to be harder to remove, to prevent tampering, or to make it clear that a component shouldn’t be disassembled by a consumer, for example, using an uncommon screw head will make it harder to do.
Flatheads are preferred for locations that will be painted frequently – like outdoor metal work, since the paint can easily be scraped out of the slot.