I was looking at some screws tonight, and it occurred to me that there is really no need for any more than one type of screw and one shape screwdriver needed.
I understand that the first screws came with the slotted top out of sheer ease, but the phillips head (the cross) blows this out of the water for ease of use.
There are also the hex heads (for an allen wrench, for example) or a star head (for I assume setting torque specs., but not altogether sure).
At the end of the day, though… the only one that serves any purpose outside of holding things together is the torque head… I’ve never personally had to torque a screw to a certain specification, but assuming this is a possibility, then fine… use this screw head for ever screw application, thereby leaving you the option of torquing if you need to, but for the vast majority of applications, you’d just screw it in.
So, what gives? Why the continued production and use of all these other shapes? Everyone’s life would be much easier if you only had to keep one or two screwdrivers on hand for EVERYTHING!
The folks who make things are only interested in how easy it is for them to put things together. They aren’t quite so interested in how easy it is for you to take them apart afterwards.
Phillips head screws were designed to be self centering for ease of use with automated machines. The machines at the time weren’t so good at detecting when the screw was fully seated so the screw is designed to cam out to limit the torque. Torx head screws (which is what I am assuming you are calling “star head”) worked better and could be more controlled, and were designed not to cam out, but they required automation equipment that had some mechanism to limit the torque applied. Hex head screws were also designed for ease of automation in manufacturing. There are many other types that you didn’t mention (Robertson, pozidriv, spline drive, etc that were all also designed to ease manufacturing.
There are also a few oddballs that are specifically designed to be difficult for you to remove, as a security type of measure. They don’t want you to disassemble the device, so they put in security torx or one way screws or that sort of thing.
I’m still annoyed at my old fan’s casing that was held together with 4 phillips screws and 2 tamperproof screws. I can see no way to read that as anything other than a fuck you from the manufacturers.
One bonus of these many types of fasteners is that there are thousands and thousands of people out there (my husband, for instance) who will not be able to live without one of each type of tool in every conceivable size, making quite a nice living for tool company execs.
Some head types serve a valid purpose. For example, let’s say you want to drive a screw into a beam without first drilling a pilot hole. If you’ve ever tried to do that with a long phillips head screw, you know it’s impossible. You will strip the head long before you get the screw even halfway in. But try to do that with a torx head screw and you’ll break your wrist before the drive bit pops out of the socket. In fact, I’ve had several cases where I’ve actually twisted the entire head of the screw off with the torx bit still fully engaged.
This is only a minor point, but in some contexts where a screw head must be (or is chosen to be) visible, anything other than a slotted one looks horrible.
This is of course just a subjective bit of aesthetics, which may change eventually, but for now, there are contexts where an exposed slotted brass screw looks nice, and anything else looks wrong.
The best source for answers about this is One Good Turn: A Natural History of the Screwdriver, which starts out with the intriguing question: which came first: the screwdriver or the screw? There’s no need for a screwdriver if there are no screws, and there’s not point in inventing screws if there’s no screwdriver.
The OP should try building a variety of things before casting aspersion upon the things that go into building them.
If just one of my hobbies (R/C cars, trucks, boats) had to give up torx or hex screws, I’d give up the whole stinking hobby (well, maybe, or just curse everything).
You can tighten and loosen the above-mentioned screws at precarious angles with little visibility. Others screws? Not so much. Further, these screws can suffer serious am’t of wear on the head and still have a workable surface.
Don’t post this type of statement around these parts, or you’ll get the SDMB screw:
I was very, very impressed with the head on deck screws. They come with their own bit in every box of screws. I must have driven at least 1500 or more deck screws into my 16x16 foot deck. Two into every board over a joist.
Thankfully not a one broke or stripped. They went in pretty easy because the wood was still pretty wet. I do feel sorry for anyone that has to disassemble that deck in 25 years. Once that wood dries it’ll be like a brick.
The philips head on those deck screws is really well designed for torque.
Aesthetics does sometimes play a role. Slotted screws had always been the rule in firearms since the days they were individually built by gunsmiths. Some time in the 1990’s hex screws became fashionable in some applications and it is mainly for looks. They are considered particularly cool looking for holding the grip panels in place on automatic pistols, for example. The hex head screws actually cause some problems because it is possible for the user, if he doesn’t really know what he is doing, to over torque them in situations where the older slot head screw would have stripped out.
I wonder if the use of slotted screws on firearms is just because it’s always been done that way, or to make them easier to repair in the field. If you need to undo a philips or star screw and don’t have a screwdriver you’re pretty much… screwed. But you can work slotted screws with a knife or any number of other things.
On high end examples of custom gunsmithing, one of the things you see is all the screws being at the same “clock position” when they are properly tightened. This is accomplished by using screws with slightly oversized heads that are tightened into place, then ground down and a new slot cut into place at the desired clock position. I think the hex head screws became popular mainly because they offer a somewhat similar aesthetic appearance without nearly the work.
More than one type of screw? Ever try to put a brass screw into a piece of ironwood? I’d hate to put together a deck without self-piloting screws. I like the ones that have a cutting edge on the bottom of the head to self-countersink, too.
There are round heads, flat heads, fine thread, course thread, machine screws, wood screws, brass screws, stainless screws, colored screws that match specific decking material, metal roofing screws with rubber gaskets, galvanized screws, screws with threads all the way to the head, and screws with plain shanks right under the head. When you can’t get a screwdriver to the screw head, you want a hex-head screw so you can tighten it with a wrench instead.
Some screws have heads designed to require special screwdrivers, and some that will only engage the screwdriver when being inserted. Some screws have no head at all, but only a hexagonal indent in the end of the shaft to take an Allen wrench.
The world needs lots of different kinds of screws!
