It's 1904.
There's no radio, no TV, and building codes and fire safety are mostly things of the future.
“In 1904, Baltimore had an enormous fire.”
This is a story in Daniel Emervar. And a fire that was so big and it went on for so long that A, it completely overwhelmed, Baltimore firefighters, but it just lasted long enough for Baltimore to desperately call for help from neighboring fire companies. No one knows for sure how the fire started. But as the fire spread to block after block of Baltimore's downtown, the SOS went out to nearby cities.
So Philadelphia, anapolis, Wilmington, Harrisburg, and the other firefighters rushed to fight the fire, and had their hoses and they were ready to screw their hoses into the hydrants and get to work. And when they start to do that, they realized that their hoses couldn't screw into the hydrants.
There was a fundamental material incompatibility, which basically left them completely unable to do anything.
And so they just watched as more than 1,500 houses burned in one of the worst fires in U.S. history.
“When it was finally put out, one journalist said that the city looked like Pompeii.”
80 blocks had burned for 31 hours. The fire highlighted something about 1904 that we don't think about a lot today. The problem with those hoses not fitting was kind of the problem with everything. A bushel of greens weighed 10 pounds in North Carolina, 30 in Tennessee, a 50 foot truck leaving Vermont would be 25 feet too long to enter Kentucky. One of the examples I like is football won't be called football in the United States and National Sport.
No one agreed with a football list. Different teams had dramatically different size and shapes footballs.
Just a essential objective football, the football went undefined.
The early 20th century was the Wild West for standards. Everywhere you went, things were just defined differently. Before 1927, even traffic lights were different. In New York, you would stop on green. And it was different in Buffalo.
“And it just took a while before them to be like, "Oh, yeah, you should really have the same system in the same city."”
Today, we all stop at red and go on green. One of the endless standards that is so standard, we don't even think of it as a standard. Now, everything we use, every way we travel or place we visit, is held together by an agreement about how every tiny detail should be. But landing on those agreements, that took long, protracted fights, fights between regulators and manufacturers, politicians and lobbyists. And perhaps no fight was as challenging or as consequential as the battle over the thing literally holding our world together.
The screw thread. The screw thread is the way in which you achieve metal on metal, fascinating. And it turns out that the industrial world is full of occasions when you need to fasten one piece of metal or rigid object to another. Like, that's the industrial revolution. And as industry was taking off in the U.S., the disagreement over the screw thread had become dire.
A disagreement whose consequences would spiral out across the world. So you get these moments where like senators will start just talking about like the importance of the humble screw thread. I found one who said, "The screw thread is a simple device, but it ties together the whole mechanical skeleton of our civilization." Which, on the one hand, seems over a blunt, but you're like, "Is it wrong? I don't know that it's wrong." From 99% invisible and BBC studios, this is a history of the United States in a hundred objects.
I'm Roman Mars. Today, America used the screw thread to build an invisible empire. And that little thing, the screw thread is such a potent heart to notice, but nevertheless deeply consequential symbol of the way in which the United States has remade the world. Or the world has had to remake itself to accommodate the United States. Let's fast forward to the 1920s.
Almost nothing is standardized. The world is still utter chaos. That's barely an exaggeration. But the American government is starting to take the problem seriously. And luckily, there was one particular bureaucrat who was ready to tackle this chaos.
Secretary of Commerce, Herbert Hoover. When I had grown up, I had known Hoover to be the president who oversaw the depression.
I just thought, "Well, he must have been wildly incompetent.
And, you know, sure, maybe he wasn't a very good communicator or steward of the country's economic fortunes.
But he was a really good bureaucrat.
“He was deeply invested. I mean, actually sort of ideologically obsessed with standardization.”
I mean, at a time when, you know, the economy was not the most stable thing. And workers were fighting with factory owners. And sometimes that was getting quite violent. You could be on one side of that. You could support the unions. You could be on another side of that. You could be for the bosses.
And Herbert Hoover was like, "No, no, no, no, no." No, everyone's screwing this up. Because we can actually just get a much more efficient economy, and squeeze much more juice from the lemon,
if we just make the objects more efficient.
So it's what a weird technocratic strategy. But like, he's like, "Oh, like all of these arguments are just about slight profit margins, and we can get far larger ones, if we can get everything to be more efficient." And the way to do that is to just draw manufacturers into a room and get them to agree to do things the same way. Because once that happens, everything speeds up in all the friction in the economy goes away.
That was his big calling. Bringing the world of objects into peace and harmony was really a natural extension of who Hoover was. The kind of guy with a cat he named, Mr. Cat, the kind of guy who loves to fish, but not just for the sport of it. Because it promoted meekness and quieted hate in the soul.
The kind of guy who, when he went fishing, he did it in a full suit.
A starch collar, tie, and jacket under his weighters. So you're like, "He dressed up for the fish." "Oh my god, what a respectful man." "Love the guy." So lovely.
Unless you try to bend the rules. Once when Hoover was younger, he was manning the ticket booth at a college baseball game, and found himself face-to-face with former president Benjamin Harrison. And Herbert Hoover won't let him in because he doesn't have a ticket. Like this is a guy who believes in the rules.
He believes in the system. But Hoover had his work cut out from because getting everyone to agree on what that standard should be was nearly impossible. Standards are a funny thing because everyone wants to be on the same page, but no one wants to have to do that by getting on to someone else's page. And the more these industries develop, the more each corporation is invested in their own world.
There was just a lot of physical retooling that would have to be done, so you would lose a lot of capital. If you had to suddenly start making things the way that your competitor made them rather than the way that you were accustomed to make them. Yeah.
“Because not only would you have to retool, and the process of retooling your competitor is continuing to sell and develop and manufacture things.”
Well, you're like waiting for your screw thread to conform to some kind of standard. And at all that time, your competitor is going to try to snap up all your business. But do not worry, your pretty little heads Herbert Hoover has a plan. A calm, well-reasoned plan. So his move is not to pass laws.
His move is just to get to manufacturers to agree. And apparently he's shockingly persuasive in doing so. So as commerce secretary, he pulls in the manufacturers of paving bricks. And it's like, okay, there are 66 kinds of paving bricks, which is altogether too many. Can there be fewer?
Well, they're 10. And actually paving brick is relatively easy because it's just dimensional. So after talking to Herbert Hoover, there are 11 kinds of paving brick. But like, that's the easy round. He just keeps going. It is everything. So standards for lumber, cement, doors, steel, bed springs, mattresses, hospital linens, ball bearings, break linings. And then like just things that you don't think need standards to glass tumblers need to be standardized.
Not necessarily in their shape, but how many hours of boiling water can they withstand in order to be sold as glass tumblers? Six is the answer. Okay, there was an answer to that question. What percentage of new rubber on their treads must tires have? 70%. It's just like everything.
Every standard, every specification, that's the world that Herbert Hoover is trying to make. So of all these things, one great challenge was the humble screw. So could you talk about this as a challenge and what we're dealing with here when it comes to a screw?
“You have to think of the standardization of the screw as a kind of mega standardization.”
So if you're standardizing hospital linens, that's an issue for hospital linen producers. If you're standardizing the screw, that's everyone. Screws are in everything.
Even if you're producing an object that doesn't have screws in it, like hospi...
you're doing it with a machine that requires screws.
Let's zoom in on how the screw works for a second.
The thing that makes the screw hold two objects together is the screw thread, that raised ridge that's wrapped around the cylinder. That thread has a particular angle, which used to be different in different screws. The variation is not easily visible to the eye. You wouldn't look at a 55 degree screw through an angle and think it looks hugely different from a 60 degree one.
The difference is everything. The difference is absolutely everything. The angle of the screw thread has to match the angle of the groove inside the object it's going into in order for it to work. And you can't really tell if the screw is going to fit into something until you try it. And more and more, that was becoming everyone's problem.
The scale of this isn't just like people agreeing on a thing to our monkey mugs and bureaucrats in different states or whatever and coming up with legislation. This is literally every person who makes a machine and every machine that makes a thing has to agree on this. These are tiny, tiny people, like maybe you have one machine in their whole factory. Yeah, that's right.
And then you also think that basically it's a whole world that has to be reconstituted.
Like, okay, if you have a machine in your factory that is with a now non-compliant form of screw thread.
“All those spare parts that you have to buy them a new.”
So there's this recognition that getting this standardized screw needs to be done and at some point they achieve it. What when did that happen? That happens in the 1920s. It happens under Hoover and it's really hard because it's one thing to get the paving brick manufacturers in a room. But to deal with the screw thread problem, that's everything.
Screws are in everything. Yeah. And it's, again, it's one of those really tricky things. Everyone wants there to be a standard. No one wants to lose out.
They don't want it to be someone else's standard. So Herbert Hoover works his extraordinary magic and in 1924 there is a national screw thread standard. And Hoover, I just imagine him feeling like the moment of this greatest triumph in this bureaucrats life. He says now the half inch nuts screw on to all the half inch bolts. What a dream.
You took his arms. [music] Put yourself in Hoover's data mine here if you could. Like you have a screw with you.
“Like what do you see when you see this if you're Herbert Hoover?”
Yeah. So if you're Herbert Hoover, the thing that you're the most locked in on is the screw thread angle. And so the screw thread angle that the United States agrees on is the 60 degree angle. That's a huge achievement. But that means like every other screw thread no longer works.
Like at all. Yeah. So, so this consortium sort of agrees on this public standard happens. This consortium people vaguely agree they begin to make their things in this 60 degree threading. You know, this solves the problem of the US.
This is a huge achievement in of itself. But this is not what happened necessarily in the rest of the world. So what's going on in the rest of the world in terms of screw threads and things like this? It's exactly the same thing.
“But you have to imagine that all of the kind of anarchy that the United States was experiencing locally is actually even worse on a global scale.”
You know, the early 20th century is a time of rapid pace technological development. And every year that there's just more stuff being made. It starts to matter more how it's made and whether the objects can speak to each other. I think language is a really good metaphor here. What you have to imagine is that the United States is producing a growing world of industrial objects that all speak 60 degrees.
And then when those objects venture out into the world, they encounter a world of foreign objects. It means not even a language that's commenced rules, not a language that's comprehensible. They're just like, oh, you speak 55 degrees. We will never talk. There's nothing for us to talk about.
I don't know what you're saying.
We can never have any relationship with each other.
But then we're two Kimlong and demanded that we have a very real screw-based relationship with the rest of the world. So there's this famous moment when FDR is trying to explain why despite the fact that World War II has not yet hit the Americas, the United States should actually be deeply interested in this war. And in fact, might need to participate in it if not fighting, at least by supplying material. And so the way he puts it is this, suppose my neighbor's home catches fire and I have a length of garden hose.
If he can take my garden hose and connect it up with his hydrant, I might help them put out his fire.
I'm a historian.
And it's always about being a good neighbor.
“But then when you think about it, you're like, wait a minute.”
You're imagining yourself as Herbert Hoover. And you just imagine yourself raising your hand in the back of the room and being like, oh, whoa, whoa, whoa. What if your hose doesn't fit his hydrant? You've got a serious problem. And the cost of non-compliant screw threads, it's bad enough during peace, it's harder during war.
In the 1940s, as the US got more and more involved in the Second World War, it quickly became clear this was a different kind of war than we had ever fought before. So World War I was fought with horses. World War II is much more mechanized war. In fact, one of the main ways in which the United States participates in World War II is essentially acting as quartermaster to the world as supplying stuff to all of its allies. It outsources the fighting to other countries and it just, you know,
it's factories into overdrive. The problem that everyone recognizes at the start of the war is that none of the US stuff plays with the foreign stuff.
“So there's Canadian official who just says, look, you have to understand that at the start of the war,”
there's not a single gun or a single round of ammunition that can be shared among the allies. The bullets are slightly different sizes. And so one bullet doesn't fit another gun. The US bombs do not fit the UK bomb racks. And that sounds like a small thing, but like, try dropping a bomb if the bomb doesn't fit on the bomb rack. You trouble with your hands?
Yeah, you'll drop it, but not in the way you wanted to. In of course, there's a huge problem with the screws. They're in the weapons tanks and planes which all have to work in faraway places. So like think about sending a Jeep, so that's a thing that happened a lot. The United States was setting jeeps all over the world.
And first of all, it's inefficient to ship a Jeep.
So what you want to do is you want to do the IKM method and you want to ship parts of a Jeep.
“But that means you have to have people on the other ends who can put the Jeep together.”
Okay, so that's fine. But then, you know, the jeeps, of course, get a break and it's going to break down on all kinds of ways. So that means you have to have on the other part of the world people who know how to work with that Jeep. And then they have all of the parts that allow them to repair the Jeep. And you need that in dozens of countries all at the same time.
The design, construction and repair of everything that the Army had to have to survive the war all relied on screws that often just didn't fit. Throughout the war, the US spent $600 million shipping extra screws, nuts and bolts overseas to deal with the incompatibility issues. $600 million on screws. That's enough money to build 1,000 B29 bombers. So in the middle of this board, there's a meeting to try to solve some of this problem because the British recognize that they need to sort of get on to this standard.
Can you talk about that?
Yeah, so I mean, first of all, it's amazing in some ways that in the middle of the war.
While the British are literally being bombs, they're debating about screw thread standards. But of course they're debating that screw thread standards because if you don't work this out, the whole thing comes grinding to a halt. Like Herbert Hoover's point that incompatibility of standards is a massive inefficiency. I mean, that just sounds like a doorky thing to say, but it turns out if you're in the middle of a war, inefficiencies are lethal. And so you really do want to resolve the screw thread issue.
So Britain is not Britain operates on a 55 degree screw thread. So they don't speak to each other. And it's not just Britain. It's the entire British Empire. So there's already a global scale political unit that works on the 55 degree screw thread angle.
But also has become newly dependent on the industrial might of the United States. And so there are a series of Anglo-US meetings between 1943 and 1945. And I just sort of went through them all. And what you can see is the formerly proud world dominating British, just being humbled in Jason's and eventually completely given up. So the first meeting they have, like meeting one, they say, we would be willing to talk about screw thread standardization.
Okay. Interesting. Okay. Let's have that conversation. Second meeting they say, we would agree to consider re-tooling. So the screw thread standardization would happen by sadopting your screw thread is something that we would consider.
The third meeting they say, okay, we are re-tooling.
But it is just temporary. It is just for the purposes of the war. Don't think that you own us. And the fourth meeting they just say, okay, we are now in your screw thread standard. Wow. I suppose if you're in a negotiation, it helps to have the person you're negotiating with being bombed currently. Bombs are literally dropping on London as they're working all this out.
This moment, the UK agreeing to adopt the U.S. screw thread is a huge win for the U.S. For one, re-tooling everything, all the weapons and planes and jeeps, that's expensive.
“And then I think a top of it you have to see the symbolic humiliation. You know, it's one thing for the United States to declare independence.”
This is the British declaring dependence.
This is the British basically saying that in the realm of objects, which turns out to be a really important economically determinative realm,
we're going to take orders from you rather than the other way around. We benefited greatly from World War II not happening on our shores. Totally, yeah, yeah. So yeah, just like just think about World War II from a military perspective. First of all, it's happening at a moment of enormous technological dynamism. So the kinds of things that can be produced after the war, compared to the kinds that could be produced before are barely recognized.
Well, just even just the war itself is a time of great invention. And all of those inventions are going to nudge the globe toward a more united, technologically interdependent configuration. And then the war accelerates that tremendously. A single country right at the end of the war is producing some like 60% of all of the industrial products of the world is diplomatically dominant. And it got really lucky.
And you're right, like every other country's factories are bombed out and the United States's factories are going strong.
And they've never been. So you just have to get at the shocking good fortune that this country has to have been in this position, not just where it was, but when it was.
Yeah, but also like, you know, to give Hoover his props, you know, good fortune lands on people who are prepared. Yeah, like Hoover saw it coming.
“And then when does the rest of the world begin to conform?”
So once you have the United States and the British Empire on 60 degrees, it just, I mean, this is the way standards work, they snowball. You know, if there's like a few evenly matched parties and they're all doing different things, you can imagine any standard prevailing. But if you're in a world where most people do things one way, then it's in your interest not to fight it. It's in your interest to just quickly retool to get with the winning team as as soon as possible. And so the whole world is so materially dependent on what US factories are putting out that the world has to adjust.
And so the US standard prevails in so many different realms, big and small visible and invisible US standards just absolutely dominate the field right after World War II. In 1947, delegates from 25 countries created the International Organization for Standardization, a kind of United Nation for things. And object by object, standard by standard, the world started tuning itself to the United States.
And I mean that literally, Europe had always defined a concert A note as 435 Hertz, but the US is slightly sharper 440 Hertz one out.
And that was just the beginning.
“My favorite example is the stop sign. So, you know, what should a stop sign be? It's completely arbitrary, right? It's we're used to them being red and talking old, but like they don't have to be. So what's the story with the stop sign?”
So the US is advanced in auto manufacturing, so it adopts A stop sign early and it's just a local stop sign. So there's a square stop sign and a Detroit cop is like, Square is not screaming stop to me. So he clips the corners off making it octagonal and he's like, okay, well that that's clear. It's has a more obvious visual identity. And then so the United States form of stop sign proliferates in the United States and then in 1953. So not too far after World War II. There's an international standard for stop sign, which adapts the US yellow octagonal stop sign as a standard. And if you're hesitating this moment being like, wait, yellow.
That's because the US stop signs were yellow. In 1953, the American stop sign was a yellow octagon and the rest of the world just got on board. All the countries are like, okay, like, to the degree that you can have your stop signs be yellow octagons that would make it a lot easier to travel from country to country.
If we all kind of agreed, what a stop sign looked like.
It would match the traffic lights. That's a good idea. So the US despite the whole world having just agreed to do the yellow octagon.
US is like, uh, we're going to do red octagons now. And so the US just starts doing red octagons and like you just have to imagine the like unbridled fury of traffic engineers like worldwide is like, oh god, we just did yellow. You know, and then eventually the world just catches up and does red because to play by a different system as the United States is going to be to cork chaos and in this case traffic accidents.
“And I had a research assistant. We worked together to like run the numbers. And I think this is true. If you look at where the red octagon currently is adopted as a stop sign.”
You are looking at countries that account for 91% of the world's population, including North Korea.
So not only are we, you know, like, feeling ourselves in our power in this moment of getting this generalization to make a better world, you know, we're kind of like a mad king capricious. Jeffrey wants to stop signs to be red. Yeah. Yeah.
“And you have to understand the power is cutting into distinct ways. So on the one hand, the things that the United States wants for itself get adopted,”
essentially by other countries, just as a way of like surviving and having economies that work. On the other hand, the United States, unlike other countries, has the power to defy international standards. And so the clear example of this is the metric system. So I mean, one of the really extraordinary forms of standardization that happens globally is the internationalization of the metric system.
That is a France centered operation. And it happens before the United States comes of industrial age, but the United States is so powerful that it not totally alone, but nearly alone.
Among countries feels no compulsion to adopt the metric system. So it's just like, yeah, we work in pounds and inches, deal with it.
“And so like that's how you get a world where for most people on the planet football is a FIFA sport on a hundred meter pitch. And for the United States football is an NFL sport on a hundred yard field.”
Like the United States is on the one hand, voice it standards on everyone else. On the other hand, feels no obligation to adopt the rest of the world standards. At the end of World War II, the US had so much power, military bases and fleets across the world, one of the only functional industrial economies left standing, that it could have gone full old school empire, colonies, territories, the whole Victorian playbook. But Daniel says the fact that we didn't, isn't because of some grand moral awakening. It was because we stumbled on something better. What is so kind of remarkable and novel about this form of imperialism is just like how much effort the old form took of like putting troops and places and leaving them there.
And then you have some kind of governor who lives there with a staff and puts down insurrections and things like this. And you know, there's obviously elements to force power and like active power and US domination, but it's kind of a new novel form. Think that the war and the adoption of the US standard changed the nature of imperialism and colonialism. Yeah, we used to live in, I mean, this, it's tricky because things might change in the 21st century and it feels like they're changing very quickly even in 2026 this year.
We used to be the case that projecting power involves claiming lots of territory, fighting wars of pacification to do so, and then bumping up against your imperial rivals and fighting wars with them, maybe. And it seems like for in various ways the United States has haunts new ways of doing what it wants in the world. It's not free of force and it's not even free of territory the United States has hundreds of military bases around the world. But when it comes to things like the screws thread, you're absolutely right, like those those aren't handled at the point of the gun. It is true that historically empires have put a lot of energy and a lot of coercion into getting people to speak English or speak French or speak Dutch, that's not easy to do.
But the United States has during a period of globalization has been and particularly was it to start so just enormous that it acquired a gravitational force that allowed the United States to achieve a lot of things that empires have sweated to achieve in the past.
This empire building was made possible by the new screw thread that tiny thin...
A lot of U.S. power happens on an almost subterranean level. There's a lot of privileges that the United States enjoy as vis-a-vis the world. They're totally visible to people outside of the United States, but often invisible to people in the United States. It's not the only kind of power and it certainly uses its military all the time, but it's really easy if you grew up in the United States to look around the world and not recognize that all of the tailwind is at your back materially culturally in so many ways and everyone else is facing a headwind.
I mean, this is a country, essentially that was born on third and thought it had a triple.
Yeah, so like many things in the world today, there's been a long enough distance that we have a sort of, it sort of takes two generations that seems like maybe you can correct me as a historian, but there's really two generations of like not having fascism that people go, "Oh, what about fascism?" Or like what about imperialism? Or what about no vaccines? Or something like they forget what it's like to have polio. And there's a new kind of threat of an old-fashioned imperial expansionism.
“How are you perceiving this? Is somebody who wrote about this as being a subtle thing that America did to it becoming a more overt thing?”
I was really interested in this smooth functioning of US power, and what I didn't see was a willful return to the rough exertion of US power.
You know, we've had a decades-long relief from the kind of border crossing large-scale imperialist warfare that marked the 19th and early 20th centuries, and that was really helpful in two ways.
We've experienced a lot of the wars of pacification, which came with colonialism, and it also spared us the conflicts of imperial rivalry. Both of which turn out to be really dangerous forms of warfare, and I'm not saying we've been free of wars, but a lot of the conflicts have been civil in nature. It seems like we not just through Trump, but through Putin as well. It seems like we may be headed back to a different way for countries to project their power.
“And if that's true, it's going to be like a really dangerous because it's a, it's all the old kind of violence, but be now with nuclear weapons.”
Of course, even if the world returns to an old form of conquest, this quieter form of power isn't going anywhere.
America is already all the time expanding its empire. And so the screw said is a really good example of how just in like the most quotidian ways, the United States is like colonized the washing machines of India. You know what I mean? Like just like in all these little ways, the mark of the United States is already everywhere, all over the world. Daniel Amovar's truly excellent book is how to hide an empire a history of the greater United States.
“A history of the United States in a hundred objects is a production of 99% invisible and BBC studios.”
It's hosted and curated by me, Roman Morris. Our series producers are Priscilla, Aloebe, Brenna, Daldorf, and Ellie Lightfoot. Our associate producer is Isaac Fisher. This series was edited by Annie Brown and Courtney Herrell, mixing by Charlie Brandon Kang, fact checking by Amy Bracken. Our theme song is by Swanry Island. From 99% invisible, our executive producer is Kathy too.
From BBC studios, our executive producers are Annie Brown and Courtney Herrell. Our production coordinator is Shan Pelle. And the production manager is Amabel Fennigan Wright, artwork by Stephen Lawrence. 99% of visible is part of the serious XM podcast family, headquartered in beautiful, uptown, Oakland, California. And BBC studios is headquartered in beautiful, white city, West London.
If you want to get in touch or have an object for us to consider, email us at 100 objects at 99PI.org.

