I realize that there are many different types of screwdrivers (and their corresponding screws), but the two types that most people use are standard (slotted) and phillips.
We all know the frustration of a standard screwdriver slipping out of the groove, something that isn’t as easily done with a phillips. So why do so many things still have standard screws in them? Why haven’t they become obsolete? Is there any usage in which a standard is preferable to a phillips?
You can generally put a lot more torque on a straight screwhead than on a philips, as the latter will cam out under high loads. The real question is why robertson screws aren’t more popular in the US, as they’re superior to both for most applications, and are extremely common up here.
Does the Phillips Corporation still hold the patent?
Robertson screws? I’ve never heard of that kind. A google search indicates that they seem to just square headed screws. Why they aren’t used more, I don’t know. I think it’s just a force of habit to use nothing but slotted (which are annoying cause they slip out more under all torques) or phillips (which are annoying because they slip out under high torques, especially if it’s the wrong size.)
That’s a feature. The Phillips screw was designed for use with power tools.
I like the design of the Torq-Set screw. It looks somewhat similar to the Phillips, but is much nicer to work with.
Well, I heard that Mr. Robertson tried to sell the patent to Phillips, but they would give him much money, so he said fine, no robertson in the US.
Also, AFAIK, Phillips are designed to pop out at high torque, sort of an automatic torquing system. If you look closely, the sides of the flukes are beveled, not straight.
NB
Yeah, the are designed to pop out, which results in stripped screws when one is extremely tight and hard to unscrew. :mad:
Now that I think about it, I think another reason for slotted and phillips still being in use is that they are probably cheaper to manufactor than other types, especially since the facilities are already in place to do so. If more and more screws were to become square, hex, torque-set, or star headed, then it would cost lots of $$ to upgrade facilities, so I assume for that reason screw makers like to keep things the way they are.
It is hard to find Phillips head screws in Canada. The Robertson is FAR superior. It combines the non-slip feature of the Phillips with the torque of the slot head. Given the choice, I would not use anything else.
I have also seen triangular head screws and my intuition is that they would have even more torque.
The Reed & Prince head is also common. It looks like a Phillips but is more perfectly conical (the tip is sharper at the same time that the large end of the drive flutes are big), and I think the angle looks a little wider. There are enough of these that my Sears Craftsman screwdriver set has a driver for it.
Certainly one reason people don’t use square drive screws more is that they are harder to find. I have to mail-order them if I want to be sure of getting them for a project - for some reason the local Home Depots and other hardware stores often don’t carry them or only carry a few sizes.
How about those horrible screws with both Phillips and Slotted features? These are designed so that BOTH kinds of screwdrivers pop out of them.
I like Torx or other splined recesses because as I understand it they handle the largest torques and they have no angular motivation to pop out.
Robertsons are great, but a real pain if they get painted over. You’ll waste a lot of time gouging the paint out of the head before you’re able to unscrew it. If that bit can’t sit firmly in the hole, then you’re, well, screwed.
As a European unfamiliar with Robertson-head screws, I just had to look them up in a fit of feverish excitement. Imagine my disappointment to find out it’s just a square head.
Philips-head screws aren’t really used in new designs any more (though they’re still widely available), having been superceded by the similar looking Supadrive head, which in turn has been replaced by the also-similar-looking Pozidrive head. If you use the right size bit there shouldn’t be too many problems with cam-out, and in particular, don’t use a Philips screwdriver for a Pozidrive head and vice-versa.
There is a trade-off between shear-resistance of the bit and the screw head rounding off or camming out. A triangular bit will give good torque, but will be prone to shearing. A square bit will be less prone to shearing, and a hex bit will be very resistant to shearing, but more prone to cam-out. The best compromise between the two criteria I’ve found is the Torx bit, which is very resistant to both shearing and cam-out.
For the record, here’s all the popular screw heads. And if you’ve got a particularly stiff fastener that you don’t want to chew up, I can highly recommend a diamond grit paste smeared on the bit to lock it in there.
Hex and Torx head screws get more use in applications where the screws are intended to be removed and replaced a number of times.
Flatheads do get use in tiny-headed screws to allow enough ‘head’ to exist as to not overly weaken in.
When I was looking for Robertson screws here in Texas, one of the employees at the hardware store told me they were first marketed down here as security screws, and never caught on otherwise until people started using them for decks and other framing. The only ones they had are a Phillips/Robertson hybrid, and only in 1.5- to 3- inch lengths.
Robertson screws are frequently used to install decking here in the US. I have never seen them in any other application.
An advantage phillips and slot screwdrivers have over Robertson, Torx, Allen, etc. is that a single driver will fit many different sizes of screw. Of course, this is an excellent way to strip out the head if the if screw is attached very tightly. But on the other hand you are not carrying around a set of 20 tools.
Tiny screws on cosmetic pieces are usually slotted for appearances. No significant torque is applied anyway.
That seems rather unlikely, just based on the dates.
The Robertson screw was invented in 1908, 28 years before the Phillips screw. It was already in use by big corporations, like the Ford assembly plant for many years.
The Phillips screw was patented in 1936. (Actually invented by JW Thompson, businessman Henry Phillips bought the rights from him.) It replaced the Robertson screw in many cases, because many factories now used assembly lines with power tools, and the Phillips screw works better for those. (The driver slips out when overtightened, so workers can’t overtighten it and damage the product.) General Motors was a big customer for Phillips screws. Ford stayed with Robertson screws for a while, just because GM used Phillips. Mechanics of the time were annoyed by this, as it required them to have 2 sets of tools and keep supplies of 2 types of screws on hand.
The reason there is no Robertson Screws in the US is because of Henry Ford. As General Motors was using them, he decided he wanted to use them as well. He invited Robertson to his offices and demanded control of the patent. Robertson refused to give over his patent on this amazing screw to him. Henry then used his limitless power and influence to have the screw banned from the US marketplace. Typical. Don’t be surprised. This still goes on today.
Sounds like nonsense to me. How did he have them “banned”? Do you have a cite for all this?
Here is the Robertson Websitegiving the history of Robertson, the screw, and Ford. It says
So Ford was already using Robertson’s screw, wanted a say in where and how the screws would be made, but nothing about controlling the patent. Robertson declined the terms. It doesn’t say anything about being banned from the US marketplace.
I think that website would be a fairly good source of information about this topic.
Sounds like nonsense to me too.
From the link FridgeMagnet posted back in 2006, we get this short statement: