Dovetail Joints

Photograph of an old stone arch.

How do you cross a river? Well you can ford it if it's shallow but otherwise your only option is to build a bridge and this has been done for thousands of years with very little change. The way you did it was to use either arches or spans.



Photograph of the wooden Mathematical Bridge at Cambridge.

Arches are constructed using stones or bricks but to span longer distances you need a material which is long and for most of history the only long material that existed was wood - and the way you join two pieces of wood together is by making a joint. The best known joint, and most beautiful, is the dovetail joint.

Diagram of a dovetail joint.

Dovetail joint

It all changed in the mid 1700’s when the Industrial Revolution began to take its first faltering steps as iron was produced in large quantities for the first time. Prior to this iron ore had to be heated over a fire and you only got small lumps. Good for forging axes and plough shares but not enough to cross a river.

Suddenly, it was possible to pour iron into moulds and make it into long lengths.

For the first time in history it was possible to build a bridge using iron and it happened first in Shropshire, birthplace of the Industrial Revolution. The town is still called Ironbridge and the bridge is still there as you can see in this picture.

Photograph of the iron bridge at Ironbridge in Shropshire.

The iron bridge at Ironbridge in Shropshire

Close up of the dovetail joints on the iron bridge at Ironbridge in Shropshire.

But the early builders faced a problem - how do you join long lengths of iron together? Until that time iron had been worked by beating it on an anvil. No-one had ever had to join long lengths of iron together on this scale. How did they do it?

The answer is that they did what users of all new technologies do. They used familiar methods. They cast dovetail joints and pegged them with iron pegs! It sounds crazy now but for them it was the most logical thing in the world. They were at the white heat of technological innovation and they were doing new things with a new material. They used it for a familiar task and it did it better. They used iron in place of wood and they joined the pieces together the only way they knew how. Nobody at that time could conceive of the rivet or the idea of welding metal together. Doesn't this ring a bell? Isn't this exactly how we took our first steps with computers?


When I first wrote this page, back in the 1990s, I  believed that almost everything we had done with computers up until then had been little more than using new technology to do traditional tasks. We had been using dovetail joints. For example, word processing has certain advantages over pen and ink - you can erase easily and the results look professional - but it’s not a new activity. Similarly, a desktop publishing program, very popular in 2000, may bring the power of the printshop to your desktop - but it is nothing really new!

I asked what will be the first “electronic rivet"? What will be the first example of “electronic welding"? And I said that perhaps the Internet was the first really new idea. It was still fairly new back then and we accessed it using dial-up. Pages with pictures took a long time to load - but it did have new elements. The pages could be read 24 hours a day by anyone in the world. This was not possible using traditional technologies. 

Now, twenty years later, we refer to those early days of the Internet as Web 1.0. It consisted of static pages and early attempts at e-commerce. It was only when broadband arrived that Web 2.0 appeared and the world began to change. 

Broadband brought things no-one foresaw - social networking, user-generated content and “clicks-and-mortar shopping” among many others.  

Superfast broadband is going to be the next big step but again, it’s pretty well impossible to foresee what changes it will bring. Even the advertisers have no idea. “You’ll be able to download a film faster,” they say, as if that will be the sole benefit. Superfast broadband will actually have profound consequences - it’s just not possible for our brains to make that conceptual leap.

To see an example of this from the past read the next article. It's all about the Linotype machine and is called “Job Losses”. In fact, a better title might be “Unexpected Consequences”.

Before you leave this page you might like to see everything I’ve just written in video form. It’s a film I made at about the same time I was originally writing this article:


Next: Does New Technology Cause Job Losses?



© Brian Smith 2015