Do you know how many different screwdrivers and screw heads there are in the world?
Too many. There's too many.
Here is my whole collection of screwdrivers (I actually took out a few),
as well as this kit of mouthpieces that I love, and this one.
So why are there so many? Why isn't there just one screw
that has taken over all the others?
There are valid reasons for the existence of all these screw heads.
And by the end of the video, you will be able to say which is your favorite
screw even though you have probably never used it... because of two men
who failed to get along in the 1930s.
And today, in 2021, the screw that you probably use the most... is the worst.
I don't have an innate passion for screws, it was a topic that left me
indifferent until not so long ago, but I had the opportunity to work
with very special screws during my PhD.
These are orthopedic screws.
They are used in spine surgeries in particular to hold metal rods.
And a screw like this, just one, costs over $1000. And on average, we would
use about twenty per patient for the surgeries that we were working on.
So these are very specific screws of course, particularly the head, and
even though I don't think that justifies their price, (but that's
another story)... it's working with these special screws that got me wondering:
"why are there so many screw heads for everyday use?"
I've been working on this video for months, and at every "party"
with friends I talked about my screws... so this video is a special treat to myself.
We may go into completely unnecessary but really interesting detail.
The most common screw is this one, this is the cruciform screw.
Well... at least that's how I called it when I lived in France.
But here in Quebec, it's called a Phillips screw.
So I have long believed that cruciform and Phillips were synonyms, regional names
for the same thing.
Like T-Shirt and chandail, buttocks and foufoune, flip flops and boubounes, panties and bobette, thing
and cossin, hello and allô, delicious and écoeurant, smoke and bucane, bucket and chaudière,
spoiler and divulgâcher, shopping and magasiner… And the list goes on.
But no, not at all.
The term cruciform simply means that it is a cross shaped screwdriver.
And there are plenty of cruciform screws: the Phillips is one, rather American, the Pozidriv
is more European, the JIS is more Japanese, or even the Frearson (which I don't have)
the Supradriv, the French recess and I imagine that there are many more... All of these
are cruciform screws.
And even if the Phillips screw is the norm, especially in the United States, it's also very common
in Europe (for those who follow me on Instagram, that's why I asked you for a
photo of your screwdrivers a few months ago, I wanted to check which screws you had at home).
So not only are there plenty of types of heads but within each type, you will find
many more sub-sections.
There are so many varieties for mechanical reasons but also
for historical reasons.
Are we talking history? Well, it is pretty difficult to date the very first
screw, but the first that were produced commercially were slot screws
towards the end of the 1700s, early 1800.
Okay, slotted screws suck. The screwdriver
doesn't stay in place, it keeps getting out of the slot… but we knew how to make it.
That was their main advantage at the time.
In the late 1800s, people were generally fed up with these poorly performing screws and it
resulted in the filing of a whole bunch of patents that tried to fix these problems
with magnetic bits to hold on to the screw while it is inserted
in the right hole.
But the real solution was to correct the problem directly at the source...
and get rid of the slot head, to get a new shape of the screw head.
For example, the Phillips screw head.
The Phillips head arrived in the early 1930s but before that
there were others...
Tatata.
I'll stop you right away.
We're not going to tell this story chronologically, because ultimately the screw that
will be your future favorite screw, at least I'll try to convince you of it, was
invented before the Phillips one.
And I would first like to demonstrate just how unsuitable the Phillips screw really is.
Right, why respect chronology, it's not like I care...
Let's take a step back and think about the role of screws.
Particularly, the role of a screwdriver.
What do you expect from a screwdriver?
You may have never pondered upon this particular existential question before,
so allow me to answer it for you.
We expect 3 things from a screwdriver.
First, we want it to fit into the screw head without any problem.
Then, once inside, we just don't want it to move about, it must be stable, and stay in the hole.
And finally, we want the rotational force that we apply with our hand to be transmitted
effectively to the screw.
And this rotational force is called torque.
The term "torque" has nothing to do with a romance between a screw and a screwdriver (torque=couple in FR),
it simply indicates that the rotational movement of the screw comes from 2 opposite forces
of opposite direction. Here's an example.
When you open a jar of jam.
My thumb pushes towards there while the rest of my hand is pushing the other way.
But in the end, it rotates, thanks to the torque.
So the Holy Grail would be to have all three properties.
And on this diagram, the Phillips screw... we would place it there:
Despite everything, compared to the slot screw, the Phillips screw was a blessing
at the time.
We finally had a screw that required the screwdriver to come directly to the center thanks to its
beveled profile.
But the Phillips drama is summed up in a Wall Street Journal article from 1988,
even more adamant against Phillips than I am.
Mr. Phillips persevered - to the misfortune of many modern-day handymen.
Which brings us to the real scandal behind the invention of the fiendish screw:
it was designed to cam out as it was driven in by automated screwdrivers,
so the screw head wouldn't be ruined.
An evil plot? Some bruised handymen think so...
Each era has its social dramas.
In 2020-2021, it is the pandemic, in '88 it was the Phillips screws.
Phillips was therefore accused of having conceived a screw which, as soon as you start to put
a little force in its tightening, would bring the screwdriver out of the screw recess automatically,
which is something we have all experienced before.
This phenomenon is called the cam-out, and it results in the screwdriver getting dislodged
from the screw and head; the issue comes from the design of the screwdriver itself.
You'll see.
Do you see this angle? This is the culprit for the screwdriver's removal.
Right, we agree that when I turn my screwdriver, I'm applying a rotation.
This rotation, we can break it down into a force towards here and a force towards there.
The torque we were talking about earlier.
Now let's have a look at the tip of the screwdriver.
We have this force coming from the screwdriver which is passed on
to a sort of fin.
But since there is an angle.
When the fin comes into contact with the screw, there is a reaction force from the screw.
Like me right now, sitting on this chair.
I apply my weight to it and it, in return, holds me up (I can feel the chair under my buttocks).
And it's applying force to me.
If that force weren't there, I would go right through the chair.
This is the action/reaction principle.
Same thing for the screwdriver, it applies a force on the screw but since it doesn't go
through it, it means that the screw is applying an opposite force.
This force is perpendicular to the angle of the fin.
And since this force is at an angle, it pushes partially against the screwdriver,
directly as a horizontal force that produces a rotation (the force we want),
but it also pushes upwards.
And it's this force that dislodges the screwdriver.
On top of that, since the angles of the screwdriver are not the same as the angles in
the screw's head, we end up with a lot of play between the two.
The screwdriver is not stuck in the screw at all.
So obviously, the screwdriver doesn't fit too well, AND we have a force that pushes it out,
that explains why it keeps falling out.
That is why when you're screwing a Phillips screw, you're having to press hard on your screwdriver;
to compensate for the force that tries to push it out.
But the more force we put into the rotation, the more the screwdriver is pushed back by the screw
and there is a point where it slips.
Which ends up damaging the screw and/or the screwdriver, until it is
no longer possible to tighten or loosen the screw.
In short, the Phillips screw sucks.
But it's not the only screw that has this kind of problem, it's just the worst one.
The other cruciform screws have largely dealth with the problem by tweaking their angles or
by adding fins as on the Pozidriv.
It’s not as big of a fin but it’s something.
In fact, any cruciform screw other than Phillips will perform better.
I've been saying "le Phillips" or "la Phillips", I don't know if it's a male or female word #FrenchProblems
Pardoxically and quite ironically, the fact that the Phillips screws automatically cams out
was an advantage for old production lines
which did not really master their tightening torque.
With a screwdriver that falls out as soon as you apply a little too much force on it,
you can be sure you won't over tighten anything.
But for the rest of the planet, it is hell.
So know that it's not your fault if you are unable to screw.
It’s not you.
It's Phillips.
The Phillips screw we know is already an improved version of the original.
It wasn't Mr. Phillips who came up with the idea,
but Mr. Thompson, who never managed to sell it.
Phillips bought the invention off of him, perfected it and then he sold
user licenses, in particular for the production of the Cadillac in 1936
just before World War II, when the demand for screws skyrocketed,
which resulted in Phillips' domination of the screw market,
{screw puns in French}.
The 'evil plot' accusation is apparently unfounded
and may have come from a language misunderstanding.
The term “cam-out” found in Phillips' patents, which nowadays designates
the fact that the screwdriver comes out of the screw, does not meet the definition of “cam-out”
from the 1930s.
The confusion would come mainly from the fact that we have
too contemporary an outlook upon reading the term cam-out.
We agree that the design is bad, but it is not intentional.
Enough about the Phillips screw (although I still have plenty more things to say),
let's move on to a screw with an intentionally good design.
The best screw of all, which you probably don't know if you are in Europe:
the Robertson screw, or Robbie for close friends. A Canadian invention that remained Canadian.
It was in 1906, almost 30 years before the invention of the Phillips screw, Peter Robertson,
a Canadian, cuts himself with a screwdriver that slipped off the screw.
Instead of sulking, he invented a new screw.
A square head screw that today bears his name: Robertson.
Since the angles of the screw and the screwdriver are the same, you can just place the driver into the screw
and it holds! I have no magnet here. It holds because it's a good design. (That's right, Phillips.)
It means that you can screw something with just one hand. Unlike most other screws.
So you can do two things at the same time.
No need to press on the screw like a mad person to counteract the dislodging force like you would
with a Phillips screw, since the angles of the Robertson screw
are much less marked.
If it's so good... how come Robertson screws are only exclusively used in Canada?
It’s a matter of rights.
Henry Ford had estimated that he could save 2 hours of assembly time on
the production of his cars if he used Robertson screws.
So he tried to buy a license to produce it himself...
which Robertson refused... wishing to keep control over his screws.
So Ford went to Phillips and used the Phillips screws in his production lines,
and Phillips' design was seen around the world and democratized its use.
Nowadays, only Canadians use the Robertson screw.
But if you are in Europe, don't worry, you also have another screw that's not too bad:
the torx (or star) screw that is comparable in quality to the Robertson screw.
See, I'm not that closed-minded.
A screw connoisseur might retort that the hexagonal screw is also fine.
It isn't, my friends, it isn't.
As hexagonal screw is not as good as the Robertson screw in particular on one point:
it's easier for a screw to become stripped if it's hexagonal
than if it's a Robertson and it's easy to understand why.
Here is a hex screw.
When we put a screwdriver in it (look at my pretty model),
the screw takes up most of the space (I'm exaggerating it here). But when you keep using the screw, that will damage
the material and remove some of it from the screw.
And as soon as I remove this matter, my screwdriver will only turn on itself.
I will have trimmed the inside of the screw.
In the end, the amount of material there is to trim is just a small circle. It happens fast.
Now if we look at the Robertson screw and we do the same exercise, you can see that
there is a lot more material to trim before the screwdriver starts spinning on itself.
Hence the fact that the square screw head is more durable than the hex screw head.
The Robertson screw has much more material to remove, so it will take longer to get dull than the Phillips screw.
Hence the superiority of Robertson.
Well, despite these historical and mechanical reasons which explain why we have so many screw heads,
even if we mostly talked about the well-known shapes, there are also reasons that I would call
“the Apple model”. A few years ago, Apple developed their own screws, pentalobes... to keep us
dependent on their repair service.
Since then, this kind of screwdriver is easier to find, but the principle is the same.
The same goes for orthopedic screws.
Some designs are intentionally different just to force you to use their special kit.
Okay, but if I force myself to be more neutral, in reality, there is not a single screw that is
better, there are mostly different use cases.
A slot screw is much more practical if you have painted over it or if some
rust has formed. It's a lot easier to clean that simple shape than it is to clean any other,
more complicated shape.
Robertson or torx screws are best to screw something very tightly and with just one hand.
With Phillips screws, you don't need to aim for the hole, it will automatically
center itself in the screw and if we don't need to screw it too tight, it's actually perfect.
It hurts to say.
And so on.
There are a variety of screws because we have a variety of uses for them...
(and for intellectual property and historical reasons, too.)
I worked on this script for so long that I've had time to design a t-shirt.
It's available if you'd like one, the link is in the description.
This is just for fun, I have no special ambition for this kind of thing.
When you receive it, let me know if it enables passionate discussions with people...
once we're allowed to see people again.
So? You clicked on this video probably without much enthusiasm
and here you are at the end...
If you do not know this channel, this is pretty much how it goes.
We start off with questions that really don't sound that interesting, and we uncover the
beauty that hides behind if you look hard enough.
We geek out on details, basically, that's the channel's motto.
I hope you have learned some things, now I'm waiting for your comments
to know which you think is the worst screw and which is the best screw, although I may
have nudged your answers a little in the video.
Despite the length of this video, there's a lot I didn't get into, so you will find links
in the description for more information.
I now invite you to...
share the video
so that everyone may know which is the world's best screw.
It's important for everyone to know...
Thanks to Nota Bene for his participation.
I've been wanting to collaborate with him on a video for a long time
and I'm glad he was available for this exchange.
I think you all know him already but if not, go check out
his channel, he talks about history without the fuss.
Thanks also to Franck and Léo and Manuel… I have occupied the minds of many people
for this video.
I invite you to share the video to all your friends who have ever used a screwdriver
in their life and to subscribe if you find that this video deserves it.
I wish you a good day.
See you soon, bye.
That's it... I am 4 years old again.