eli5: Why are there different types of screwnail heads? Does it really affect the strength or integrity of the screw if the head is a Phillips, Robinson or standard?
In: Engineering
It has to do with driving the screw. Flathead is easy to make. Simply cut a slot in the head. It’s can be a pain to line the driver up with it though and it slips out and strips the head easily. Philips improves on the lining up but it cams out of the hole easily, also tending to strip the head in the process. This was an advantage in early use when power drivers didn’t have effective clutches; it made it harder to overdrive. Robertson (what I think you were referring to when you said Robinson) solved many of these problems but wasn’t adopted widely due to the way he went about licensing his patents (or so I’ve been told). Torx (or star drive as some people call it) is a further improvement on ease of lining up the driver and preventing the head from slipping and .stripping the head.
Other specialty heads exist, some trying to improve the drivability, some for security reasons. None of those designs effect how the screw performs in terms of holding or strength. There are screw designs that do that (see GRK fasteners as an example, their screws have quite a bit of thought and engineering put into them).
Editted for typos and to add a point or two.
Latest Answers