Why We Have Different Types of Screws

iStock/teerawut111
iStock/teerawut111

If you've ever mistakenly grabbed the Phillips head screwdriver when you needed a flat head, you've probably asked yourself why there are different types of screws. Let's start at the beginning.

The screwdriver, originally called a screwturner or turnscrew, entered the world inconspicuously and kept a very low profile until its 300th birthday. Historians believe it was invented in Germany, but aren't sure exactly when. The Medieval Housebook of Wolfegg Castle, the oldest known written reference to the tool, has a hazy publishing date somewhere between 1475 and 1490. Considering the invention likely predates the book by at least a few years, the mid to late 15th century is about as exact a birthday as it gets. For about 300 years, the persistent presence of screws is the only solid evidence that screwdrivers even existed. Then, suddenly, documentation of screwdrivers exploded across Europe, particularly in France.

Early screwdrivers had pear-shaped handles and were made for slotted screws. Metal screws as we know them today have been in use since at least the 15th century for cabinetry work and to secure plates on jousting armor. Before that, wooden screws were used in wine and olive oil presses as far back as the 1st - 3rd century BC (how they turned them for so long without a screwdriver, I haven’t been able to figure out).

These early metal screws were prohibitively expensive. It wasn’t until several advances in screw making – among them, Jesse Ramsden and Henry Maudslay's screw-cutting lathes and David Wilkinson’s and Job and William Wyatt’s mass production of screws on assembly line-like systems – occurred around the beginning of the First Industrial Revolution that the screw became easy enough to produce to become popular and widespread. This increase in popularity, of course, led to the refinement and diversification of the screwdriver. The tool took on many different shapes and sizes, though for a long time every version was still for flat slotted screws, which were the only type around.

Better Heads

This changed in 1908, when Canadian P.L. Robertson patented the “first recess-drive type fastener practical for production usage,” a recessed square-drive screw that bears his name. Robertson screws became a standard in Canada and gained a buzz in the U.S. when the Ford Motor Company, one of Robertson's first customers, used over seven hundred of them on each Model T. The square-drive head on Robertson screws had an advantage over slot heads because the driver was relatively easy to get situated on the head and stayed put during installation once it was there. A screw like Robertson’s became crucial as American manufacturers moved increasingly toward mass production methods. The time it took to align the driver with the slot, multiplied across thousands of workers in a factory and across hundreds, if not thousands, of screws per worker per day, became a significant loss of time and money. Additionally, the automated screwdrivers used on assembly lines often slipped out of the screws’ slots and into whatever component was being assembled or stripped the screw once it was driven all the way. [Image credit: Saforrest]

The American automobile industry was especially in need of a screws screw that could stand up to the torque of their automated drivers and be fitted and tightened quickly, but a bad break in Robertson’s past doomed him just when his invention was needed most. Dealing with dishonest parties while licensing his screw in England, Robertson wound up losing the rights to his invention and had to spend a small fortune to buy them back. When Ford, wanting to protect his assembly advantage (the screws saved his workers two hours of assembly time per vehicle), asked for a licensing agreement from Robertson so that he could manufacture and control the distribution of the screws, Robertson turned him down and he refused to allow anyone to make the screws under license. After their run on the Model T, Ford had to limit the use of the screws to his Canadian division and the widespread adoption of the Robertson screw in the U.S. fizzled and failed.

Enter Portland, Oregon-based businessman Henry F. Phillips and the patent for a screw with a deep X-shaped slot, which he had purchased from friend and inventor J.P. Thompson. Phillips refined the design of the fastener, today known as a Phillips screw, for automated screwdrivers. The X-shape of the slot and pointed tip of the Phillips head screwdriver made the driver self-centering and unlikely to slip out when it wasn’t supposed to. The recessed slot was shallow enough, though, that the driver did pop out when the screw was fully tightened, which prevented over-torquing and damage to the screw, the driver and the product being assembled.

The American Screw Company began mass-producing Phillips’ design. A successful trial on the 1936 Cadillac helped it proliferate through the U.S. auto industry. By 1940, 85% of the screw manufacturing companies in the U.S. had a license to produce the Phillips screw design. Usage spread from the auto manufacturers as the Phillips drive system was used during the Second World War on many wartime products and vehicles. Though originally meant for automated, industrial applications, Phillips screws and handheld screwdrivers found their way into the toolboxes of handy men and women across the country by the turn middle of the century. [Image credit: U.S Patent and Trademark Office.]

Other Ways the World Turns

Most anyone who’s had to fix anything at home or put together an IKEA couch has heard of slotted and Phillips screws and maybe even hex sockets. The world of screws is vast, though, and plenty of other types of screw heads and drives exist, like the Mortorq, the Pozidriv and the Bristol. You can take a crash course in the different types of screws here, and if you want a more in-depth history of screws and drivers, check out Witold Rybczynski’s One Good Turn: A Natural History of the Screwdriver and the Screw.

More Than 350 Franklin Expedition Artifacts Retrieved from Shipwreck of HMS Erebus

Drone image above the HMS Erebus shipwreck.
Drone image above the HMS Erebus shipwreck.
Parks Canada's Underwater Archaeology Team

From a shallow Arctic gulf, a treasure trove of objects from the HMS Erebus shipwreck has been brought to the surface for the first time in more than 170 years. The items could offer new clues about the doomed Franklin expedition, which left England in 1845 to search for the Northwest Passage. All 129 people perished from still-uncertain causes—a mystery that was fictionalized in the AMC series The Terror in 2018.

Marc-André Bernier, head of underwater archaeology at Parks Canada, said in a teleconference from Ottawa that this year’s research season was the most successful since the discovery of the HMS Erebus shipwreck in 2014. Parks Canada divers and Inuit located the HMS Terror, the second ship of the Franklin expedition, in 2016.

Parks Canada diver at HMS Erebus shipwreck
A Parks Canada diver retrieves a glass decanter at the HMS Erebus shipwreck.
Parks Canada's Underwater Archaeology Team

From mid-August to mid-September, 2019, the Parks Canada and Inuit research team began systematically excavating the large and complex shipwreck. “We focused on areas that had not been disturbed since the ship had sunk,” Bernier said. “Right now, our focus is the cabins of the officers, and we’re working our way toward the higher officers. That’s where we think we have a better chance of finding more clues to what happened to the expedition, which is one of the major objectives.”

Over a total of 93 dives this year, archaeologists concentrated on three crew members’ cabins on the port side amidships: one belonging to the third lieutenant, one for the steward, and one likely for the ice master. In drawers underneath the third lieutenant’s bed, they discovered a tin box with a pair of the officer’s epaulets in “pristine condition,” Bernier said. They may have belonged to James Walter Fairholme, one of the three lieutenants on the Erebus.

HMS Erebus shipwreck epaulets
A pair of epaulets, which may have belonged to third lieutenant James Walter Fairholme, was found at the HMS Erebus shipwreck.
Parks Canada's Underwater Archaeology Team

In the steward’s pantry, where items used to serve the captain were stored, divers carefully brushed away sediment to reveal dozens of plates, bowls, dish warmers, strainers, and more— about 50 serving pieces total. Bernier said some of the most exciting finds were personal objects that could be linked to individuals, such as a lead stamp with the inscription “Ed. Hoar,” for Edmund Hoar, the 23-year-old captain’s steward. They also found a piece of red sealing wax with a fingerprint of its last user.

Dishes at HMS Erebus shipwreck
Divers found dishes in the steward's pantry at the HMS Erebus shipwreck.
Parks Canada's Underwater Archaeology Team

Other intriguing items brought to the surface include a glass decanter, found in the officers’ mess area on the lower deck, which may have held brandy or port; a high-quality hairbrush with a few human hairs still in the bristles; and a cedar-wood pencil case. All of the artifacts are jointly owned by the Government of Canada and Inuit.

Hairbrush from HMS Erebus shipwreck
A hairbrush discovered at the HMS Erebus shipwreck still had a few human hairs in the bristles.
Parks Canada's Underwater Archaeology Team

The extensive recovery was made possible by a new research barge, which was moored over the shipwreck and provided hyperbaric chambers and hot-water suits. While wearing the suits, divers were able to stay in the frigid waters for about 90 minutes at a time; they spent over 100 hours examining the wreck this year.

The HMS Erebus’s size and excellent state of preservation mean there’s much more to discover, Bernier said. The Erebus is 108 feet long, and though the upper deck has collapsed, there are 20 cabins on the main deck. They’ve examined only three so far. “There are tens of thousands of artifacts still there,” Bernier tells Mental Floss. “We’re going to be very focused and save what needs to be saved, and go to places [in the wreck] where there are good chances of finding the most information that is valuable for the site.”

Parks Canada and Inuit archaeologists
Parks Canada and Inuit archaeologists set up instruments near the HMS Erebus shipwreck.
Parks Canada's Underwater Archaeology Team

As with the findings from previous research seasons, many questions about the shocking demise of the Franklin expedition remain unanswered. How and when did the HMS Erebus sink after both ships were abandoned in spring 1848, having been trapped in ice since September 1846? Which officers and crew were among the 24 men who had died by that time, and why so many?

Bernier tells Mental Floss there’s even a new mystery to solve. Near Edmund Hoar’s items, divers found another artifact that also bore the name of a crew member—mate Frederick Hornby. “Originally, when the ships set sail, he was not on Erebus, he was on Terror,” Bernier says. “So this object jumped ship at one point. How did that happen? Was Hornby transferred to Erebus; did they abandon one ship and put everybody on the other one? Was it something somebody recovered after he died? Was it given to somebody? With one object, we can start to see [new] questions. Hopefully, by piecing all of this together, we can actually start pushing the narrative of the story in some interesting direction.”

The Scottish Play: Why Actors Won’t Call Macbeth by Its Title

Macbeth and the three witches in Shakespeare's possibly cursed play.
Macbeth and the three witches in Shakespeare's possibly cursed play.
Photos.com/iStock via Getty Images

If you see someone burst from the doors of a theater, spin around three times, spit over their left shoulder, and shout out a Shakespearean phrase or curse word, it’s likely they just uttered “Macbeth” inside the building and are trying to keep a very famous curse at bay.

As the story goes, saying “Macbeth” in a theater when you’re not rehearsing or performing the play can cause disaster to befall the production. Instead, actors commonly refer to it as “the Bard’s play” or “the Scottish play.”

According to History.com, the curse of Macbeth originated after a string of freak accidents occurred during early performances of Shakespeare’s 1606 play. In the very first show, the actor portraying Lady Macbeth unexpectedly died, and Shakespeare himself had to take over the role. In a later one, an actor stabbed King Duncan with an actual dagger rather than a prop knife, killing him on stage.

Macbeth has continued to cause calamity after calamity throughout its four centuries of existence. Harold Norman died from stab wounds sustained during a fight scene while playing Macbeth in 1947, and there have been several high-profile audience riots at various performances, too—the worst was at New York’s Astor Place Opera House in 1849, when fans of British actor William Charles Macready clashed with those of American actor Edwin Forrest. Twenty-two people died, and more than 100 others were injured.

Since Macbeth has been around for so long and performed so often, it’s not exactly surprising its history contains some tragic moments. But many believe these accidents are the result of a curse actual witches cast on the play when Shakespeare first debuted it.

As the Royal Shakespeare Company explains, Shakespeare really did his research when creating the three witches in Macbeth: “Fillet of a fenny snake,” “eye of newt and toe of frog,” and other lines from the “Song of the Witches” were supposedly taken from “real” witches’ spells from the time. According to legend, a coven of witches decided to punish him for using their magic by cursing his play.

For skeptics, Christopher Eccleston—who played Macbeth in a Royal Shakespeare Company production in 2018—offers a slightly more believable theory about the origin of the curse. In the interview below, he explains how theater companies that were struggling financially would stage Macbeth, a crowd favorite, to guarantee ticket sales. Therefore, saying “Macbeth” in a theater was an admission that things weren’t going well for your company.

[h/t History.com]

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