Where DO screws come from?

so what would happen if every screw just disappeared i think everyone knows if you had x-ray vision and could see through the things around you you see that pretty much everything is held together with screws or their sibling the bolt the entire fabric of our world is held together by little bits of metal with twists in them just a simple helix wrapped around a cylinder they are so common ubiquitous and work so well that you don't even notice them at all and that's a beautiful thing but what you may not know is that screws are used in many many more ways than just to fasten things together if screws just suddenly disappeared we'd have way more problems and things just falling apart i don't want to spoil the fun but over the next few videos i'm making about screws i think you'll see the humble helix is amazingly important and profound in ways you've probably never imagined and affects you more than you know the first kind of screw we know of wasn't anything like you would usually think of instead it was used to move water probably first using the hanging gardens of babylon around 600 bc which was likely in nineveh and modern iraq today we know them as archimedes screw archimedes was the first to describe them in writing when he saw them in egypt around 234 bc the ancient egyptians living along the nile are making so much food with irrigation by several techniques including water screws like these making egypt the bread basket of the mediterranean while primarily used to convey water throughout the ages as it still is sometimes today the water screw is beneficial if not critical for other uses like in plastic injection molding snow blowers chocolate fountains or if you have one of these in your combine harvester you're looking at an idea well over 2000 years old and a better way hasn't yet been found but how else were screws used in the ancient world ancient people who wanted wine or olive oil had a big problem it's a real pain to crush the fruits to extract the juices in a maximally profitable way we know what wine was used for but everyone around the mediterranean used tons of olive oil too and it was a huge business one of the earliest known ways to extract it other than the good old feet method was to make a press there were many variations on the fruit press in the ancient world but what it really came down to was a few basic designs that used a huge beam that was pulled down to squish the fruit now to you this idea may seem impossibly out of fashion by a few thousand years but if you're like me you probably have one of these fruit presses in your kitchen too this is just a mini version of an idea thousands of years old and one of the first and most important simple machines ever made eventually someone made a huge leap by using a screw vertically through the end of the beam and anchoring it with a giant rock now you could use pole to turn the screws which tried to pick up the rock but really had the practical effect of bringing the lever down but then there was another leap in a new different press which would eventually have an incredibly profound impact far far beyond fruit pressing this new press got rid of almost everything and put the screw right on top of the fruit pressing on boards this press had the advantage of being small easier and cheaper to build and still highly effective now a single person can easily pull a lever and exert a tremendous amount of force downwards on a simple cheap machine that's also very productive or alternately you could make a larger version and employ a few people or animals to press a lot of fruit really profitably and they were used until relatively modern times but the importance of this style of press doesn't end with olive oil and wine oh no it's way more important than that in the next episode in this series you'll see how this simple style of press and the pattern of this machine is something of a ticking time bomb when combined with a few other inventions roughly fifteen hundred years later it would help kick off a chain reaction that would impact millions of people or some of the best but also some of the most horrible things that will happen in western civilization really start to unfold and which we're still dealing with today but we're gonna save that for next time remember archimedes the guy who was the first to describe the water screw earlier he's probably the inventor of a completely different way to use a screw and something we generally now call a worm drive this simple but clever device combines a screw acting as a special gear and the worm wheel which is a gear of only slightly different form the brilliance of this cannot be understated as it allows for a great conversion of rotational distance to torque in a very compact and elegant way while also turning the direction of travel 90 degrees it takes one full turn of the endless screw to advance one tooth of the worm wheel this has a great advantage of a massive reduction by however many teeth you have in your gear to one with this idea and a few other tricks like the compound pulleys he also invented archimedes also famous for designing war machines probably used worm drives and lifting devices like his iron claw that allegedly pulled roman ships partially out of the water capsizing them his lifting mechanism reputedly takes advantage of another important property of a worm drive and that you can't easily drive it backwards meaning rotation through the worm wheel won't spin the endless screw this was possibly used to great advantage in his lifting mechanisms as it meant the crank you turned wouldn't have to be held in place to keep it from spinning backwards possibly injuring the crew so we have external threads pretty well figured out but what about internal ones someone else who built upon archimedes work on screws is a man usually known as hero around the first century a highly inventive greek living in roman egypt in the city of alexandria he invented many many things that we'll have to talk about another day while it's easy enough to make decent external threads making internal threads like you'd find on a nut is very tricky indeed so he decided to invent a kind of boring machine to duplicate external threads into internal ones first he started with a block of wood with a hole board in it then from the outside he inserted some sharpened dowels that match the pitch of the thread this was a brilliant way to make internal threads without actually making internal threads from there it was easy to make an externally threaded screw chiseled out in the usual way and then onto that he added an extension into the extension near the end he put a metal cutter that he could raise up and down per pass then he placed another piece of wood with a whole board in it in front of this and then over several passes and much more slowly than this of course raised the cutter bit by bit and slowly bored out the work piece and by this method he could make internal threads without starting with internal threads with this internal thread cutting machine look what's really happening here this is a very early instance of a mechanism which is removing the skill of the operator from the equation and putting it into the machine it takes a skilled person to cut the first master thread but after that with only a little training someone else could run a machine like this and make a beautiful complex part an internal thread and do it again and again with high repeatability and this is the basis for our mass-produced industrial world putting the skill into mechanized machines that we just feed raw material and power remember the pattern of this particular machine we're going to see it again hero used as relatively high quality screws and gears in a number of ways and one of them was in something called the dioptra which was a high quality surveying instrument driven by worm drives on two axes i have an antique telescope mount that works in exactly the same way though only on one axis this is literally the same mechanics as a device about 2000 years old like mine heroes dioptra presumably had a scale on it as well so you could understand how much you've moved as you turn the screws doesn't that make it some form of early micrometer but what about the small metal screws we're so familiar with where were they first used we have to jump ahead to the late medieval period to germany in the late 1400s the germans of this period had very advanced mining metalworking technology and highly skilled artisans it was probably here that metal screws and bolts were first semi-regularly used as fasteners showing up in 15th century german plate armor as one example so hey real talk i have to step aside here and discuss an important topic there will be exceptions but very broadly speaking the difference between a screw or a bolt is a bolt goes through something unthreaded and has a nut or something else threaded on the other side a screw is put into something usually unthreaded and makes its own thread as it goes in and of course there's all kinds of things called screws or bolts that aren't fasteners at all please argue about this in the comments and show your counter examples as it is tradition whenever someone brings up screw versus bolt going forward i will use screw to mean screw or bolt and let you figure it out okay back to armor screws were more likely to be found in high quality tournament armor rather than the field armor worn by the lower ranks typically rivets or other kinds of fasteners were used in most places and screws only were truly needed we actually don't know much about thread making in these times sometimes the screws were just driven through the armor plate in a self-tapping manner usually into areas which have been thickened so would have greater bite for the threads so if you have screws you have a screwdriver right actually no because screws were so uncommon at this point why bother to make a dedicated tool plus a screwdriver is such a simple device they were just added onto the ends of handles on other tools while you might think your multi-tool is a new idea it's actually been around for many hundreds of years also from around this time there is a remarkable german document from around the 1480s often referred to as the medieval house book something of a how-to manual for lords and nights but it's also proudly showing many of the wonderful drawings of machines processes and devices often with the new crazy technology the screw although we can't see the screws it does show the kinds of armor that would have had them and in the other drawing screws start popping up everywhere one remarkable example is screws being used to regulate the angle of cannons much like hiro used screws for precision adjustments in his dioptra now screws are being used to angle cannons on two axes i've not been able to find any other illustrations of canon's ever actually being made like this so if someone has a reference i'd love to know more about it and while we'll talk about this in more detail in a bit screws take a bit of an ominous turn showing up in various tools you'd keep in your dungeon what's especially remarkable is they bothered to draw a small screw that appears to be slotted which tells you it's important to them this implies a screwdriver but one is never shown also this drawing clearly shows a wrench to be used to turn nuts both square and hexagonal on their torture instruments and then out of nowhere it seems like a spaceship coming down from the sky no not the guys in ridiculously pointy shoes showing some of the ways to assault a tower but on the other side of the page where a surprisingly complex screw cutting lathe is shown the lathe is shown in two parts the first is the frame which includes the master screw and the work piece to be cut here with some threads already cut in it and then below it the cutting part of the lathe is removed so we can see it more clearly it fits into the frame of the lathe in the slot under the master screw in the work piece held in place by a wedge and look what a giant leap this is not only do we have a removable cutter a tool bit like is still used in lathes today but also a cross slide regulated by an internal screw remember a hero's machine for cutting internal threads well this is a highly refined version of the same idea but for copying external threads with a bunch of modern stuff thrown in imagine how when you turned the crank the master screw would push the work piece forward past the cutting tool copying the thread of the master for the second time this is another incredible moment where the skill is put into the machine not the person operating it in a time when everything was made by hand one at a time this is remarkable you'll also notice the illustrator made an error the master screw is right-handed but the screw being cut which should be the same pattern as the master is left-handed oops and for a second time remember the pattern of this machine we're going to see it again what's also remarkable in this illustration is some scholars think this is the first illustration we have of a dedicated screwdriver well looking at it closely i think this is more likely like a hex nut driver like this one where it's recessed on the inside i think it clearly was meant to work the end of the cross slide to advance the cutting tool still this is quite possibly the first illustrated dedicated hand tool for turning a screw there's another spectacular german document from a little later known as the luffelholz codex it's full of truly amazing skillfully hand-drawn images from around 1505 with what seems like screws popping up on almost every page well when they weren't messing around balancing items off tables the skill of the german craftsman of this time is really put on display here and screws start popping up in all sorts of new places like these fancy workbenches showing screws being used for work holding or these absolutely beautiful compasses and calipers that must have used very finely crafted screws like in the medieval house book we briefly saw some of the tools that you can use to deal with people you don't like there are of course countless ways to inflict pain upon people and humans have been quite creative with this and the screw allowed for new simple compact methods for inflicting pain in this document we see a number of screws employed for crushing various body parts with thumb screws you can inflict intense pain on someone as fingers and thumbs have lots of nerve endings small simple something you can just pop in your pocket and highly effective thumb screws proved very popular and several versions are shown in this document when you hear the popular expression turning the screws on someone these are the screws they're talking about if you can read 15th century german script like this i'd love to hear from you i'm sure there's a lot i'm missing on many pages because i can't read the script thanks to the relatively recent import of the chinese invention gunpowder we start seeing firearm technology illustrated this wheel lock mechanism to ignite the gunpowder was complicated to manufacture borrowing heavily from the other cool technology of the time mechanical clocks but what we care about today is the four screws that held it in place with the violent and strong forces of a firearm small screws bite into wood and hold better than a small nail wood and although the first metal screws and bolts were possibly used in armor like mentioned earlier those were not commodities probably the first really wide use of small metal screws at large scale was as fasteners and firearms which kicked off industries in germany and france in particular for screw making specialists these are obviously very fancy guns but it was soon common for firearms of all kinds to have screws remember hero's internal threading machine which may have been the first machine to make internal threads or the screw cutting lathe from the house book they basically had a handle on one side which drove a master screw which moved a work piece past a cutting tool copying the thread about 500 years later this exact pattern of a machine would be used again but for a very different purpose and one you owe a great deal of debt too in 1877 a man in menlo park new jersey used that same machine pattern not to cut screws per se but to make grooves into a tin foil covered cylinder mary had a little lamb and everywhere that mary went the lamb was sure to go that man was of course thomas edison and he had invented the first machine which could record and play back sound of all the inventions he would have a pardon he was extremely proud of it and said this was his favorite though i have no clue if he was directly inspired by those earlier machines i think is more likely just an elegant solution to a similar problem for various reasons edison would eventually lose out to the flat circular records we know today but his cylinders did have one big advantage you could record onto them unlike the flat records so these machines lived on until the 1950s and you know what i happen to have one and i didn't just buy it for this video either i bought this when i was a very young man and was fascinated by its beauty and what it stood for and it's been on a shelf wherever i've lived for decades this one was made probably in the late 1920s at first mine doesn't look like hero or the house books lathe or even edison's first prototype models until you turn it around and then there is the master screw to guide the cut of the helical groove it's the same exact principle as hero in the housebook screw cutting machines just slightly modified to be folded back on itself connected by an internal clutch in the decades i've owned it i've never tried to use it maybe in a future episode so there you have it the first episode on the history of screws we've seen screws used in many different ways from raising water to fruit presses war machines the worm driving precision measuring then into armor firearms torture devices early screw cutting machines guns to the machine that brought us recorded media which is the oh so distant ancestor of you listening to me now there's so much more to the history of screws though as they've been used in so many other ways thankfully we do have screws as fasteners though and i think we're all happy that they can hold the world together if you want to know more the next stop on your journey is to hit the thumbs up subscribe and bell buttons if you haven't already it really does help get the word out and helps keep me going did you learn something today what do you think about screws what screws are around you right now let me know in the comments thanks for watching i'll see you next time [Music] you

Channel: Machine Thinking

Views: 1,294,834

Keywords: screws, machine, machine thinking, shop, precision, bolt, thread, nut

Id: yzMU8rH4PN8

Length: 18min 32sec (1112 seconds)

Published: Tue Nov 17 2020

Reddit Comments

[u/Uhdoyle]

Yes, I would like to know more. Subscribe to screw facts.

[u/errant_capy]

Naw, I subscribe to Screws Quarterly so I'm all up to date. They're thinking of switching to lefty tighty just to mix things up.

[u/LaserGadgets]

Without scews....we would all be SO screwed ><

Yeah I had to :>

[u/Bubmack]

Im bolting.