What is an Actuator In-Depth: A History of the Threaded Screw
What is an Actuator In-Depth: A History of the Threaded Screw

What is an Actuator In-Depth: A History of the Threaded Screw

by Ajay Arora

The journey from the invention of a threaded screw to the modern threaded screw has taken us over 4,300 years. That's quite a long time considering the threaded screw is something the majority of the world doesn't spend much time thinking about. Every time you turn a screwdriver in the process of building a house, you can thank 1,000 years of innovation. The next time you drive your car, and screws used to build that car, whether they were used to build the car itself or used in the machinery that built the car, the threaded screw took over 4,300 years to make it to that car.

The Real Inventor of the Threaded Screw

If you really want to get down to business, the actual inventor of the first screw is nature. Today's screw is an expression of the helix or spiral. The evolutionary benefit in spirals can be found everywhere, not to mention in your DNA. You just have to look at a snail's back, the way a vine climbs up a tree or the helix patterns on some seashells to realize that nature thought of the screw long before we did.

Ancients saw these screw patterns and started putting them to use. They didn't use them in any scientific way but adorned their weapons and jewelry with these patterns. The first instance of man-made screw patterns goes all the way back to 2,500 B.C. It took approximately another 2,250 years for someone to view the screw pattern as a useful tool.

Screwy Archimedes

The concept of the screw as a tool is thought to have been born sometime between the years 287 B.C., and 212 B.C. These are the years in which Archimedes lived. He is considered one of the first scientists to make major contributions in the age of antiquity. He was so entirely dedicated to science, in fact, that he was run through by a soldier's sword because he refused to pull himself away from a mathematical problem when we was captured during war. During his lifetime, he developed the first screw, simply known as Archimedes Screw. It was a device used primarily to haul water out of large boats, and there are boats that still use this concept today.

Some believe that using the threaded screw to create motion can be attributed to Archytas of Tarentum, but nobody really knows. He was another notable scientist during the time of antiquity, living somewhere between 428 B.C., and 350 B.C.

Right to Business

Making liquor was one of the first places we saw threaded screws emerge in history as tools. They were used to squeeze juices from grapes - and also oil from olives. These old threaded screws have been found in archaeological digs in Pompeii and in many other spots around the world. Making liquor wasn't the only job of the threaded screw. The ancients found this tool to be highly useful in a number of tasks. The Romans found them very useful as water screws (Archimedes screws), medicinal presses, odometers and much more.

After this, the screw soft of faded into the background. Nobody seemed to care anymore that the screw existed until the 15th century, when it suddenly resurfaced for use in boats again. It doesn't mean it wasn't used, it just means we don't have much evidence that there were innovations during this time.

Up until the 1700s, the creation of a threaded screw was performed by hand and the accuracy of the job depended on how skilled you were at it - not many were. The need for precise screw threads was high, and sometime around 1750 one was constructed. Antoine Thiout, a French clockmaker who was presumably tired of threading his screws by hand, designed and built the first lathe that had a screw drive. We can only assume that this design was garbage, because just 20 years later, Jesse Ramsden came along and built one that has been more than once called a 'satisfactory' screw lathe.

The design still had some problems. Even though the lathe could turn at a constant rate, the tool used to create the thread still had to be held with a very steady hand. A talented inventory and tool and die maker, Henry Maudsley, decided to create a system in which the tool could be clamped in one place, getting rid of the need to hold it in one spot. This greatly improved the accuracy of lead screws.

The Industrial Revolution

Henry Maudsley's new design was completed sometime around the 1780s, and the Industrial Revolution was just around the corner. The threaded screw could certainly be thought of as one of the signatures of the Industrial Revolution. With the invention of mass production and factories, this new, precise threaded screw was a godsend, but there were still problems. There was no standard by which to cut every threaded screw. If you wanted 100 screws from three different people, you would inevitably get at least three different widths. By collecting a massive number of screws from workshops in Britain, Joseph Whitworth decided that thread flanks should be 55 degrees and the number of threads per inch should also be standardized. The British government agreed.

After many more updates to the standard threading agreements, we have our modern screws. That's certainly not the end of the story, though. Industries and engineers are constantly designing new screws and better designs. So long as there is new technology and improvements to old technology, there will always be a need for new threaded screw types.

Nearly everything would fall apart if all the lead screws on earth just disappeared. Even though we don't think much about it, and Archimedes may not have thought about how important his invention was either, we are extremely reliant on the threaded screw and everything it has helped us accomplish. From a house to an airplane, a satellite to a toy car, the threaded screw keeps us together in all the right spots. So, the next you're buying a 24-cent screw, the quarter you paid with is giving you over 4,300 years of innovation, too.

Anna Sapiga

AZ Engineer