[calvinmorrison]

Phillips Heads: The design is often criticized for its tendency to cam out at lower torque levels than other "cross head" designs. There has long been a popular belief that this was a deliberate feature of the design, to assemble aluminium aircraft without overtightening the fasteners.[15]: 85 [16] There is no good evidence for this suggestion, and the property is not mentioned in the original patents.[17]

[arghwhat]

They describe it as a feature in their later 1942 patent (US2474994A), in the description of which they mention it to protect against powertools with poor torque control, claiming that a better screw would only be possible if power tools and their torque control were perfect and that it is therefore a required feature.

The original designs did not reference this though, so it seems more like them adopting an observed behavior as a feature - so the statement that it was originally designed to be that way is indeed off, but the company did adopt the behavior in official paperwork.

[sandworm101]

It has more to do with manufacturing techniques. Screw heads are stamped. A cone shape, with all sloped sides, is easier to stamp reliably. Even the famed Robertson bits from canada have a slight slope for this reason.

[babypuncher]

If I were to speculate, the point of phillips head was to just be easier to use than flat head while still being easy to manufacture 90 years ago. The better heads introduced since then have more intricate designs that require more precise manufacturing than a simple stamp

[bmacho]

https://en.wikipedia.org/wiki/List_of_screw_drives#Phillips

[wildzzz]

I work with a product that has to use Philips head for one specific area. I hate those damn screws. They all need to be torqued to a specific value and this requires putting an significant amount of force axial to the screw to keep the driver from slipping. If you do slip, you'll probably strip the head and now it needs to be replaced. It doesn't help that there's a gasket around the plate that adds extra running torque. Good luck getting a countersunk #2 screw out. The rest of the product uses hex heads so those are incredibly easy to install.