From children to adults, Leonardo Da Vinci’s inventions always catch everyone’s attention. Not only because of the thing he intended to achieve in the time when he lived, but also because of the limited resources there were at that time to do the things he did, and even because of how beautiful his inventions were. And regarding to the last thing I have just mention, it has a lot to do with the fact that is inventions were largely made of wood.
Copying any of Leonardo Da Vinci’s inventions in our home workshops, even today and with our modern tools, would take a lot of time and a lot of headaches. But one of his projects, the self-supporting logs bridge, does seem like a project within our reach. At least if we make it in a smaller size. So in this post we are going to see how to make the Leonardo Da Vinci bridge. Whether it is his invention, or whether it is an invention from the Chinese, we will leave for other debates.
Selecting and cutting treated wood posts
The first thing to do is to select the logs to make the self-supporting bridge. I decided to use treated wood posts, as this Leonardo Da Vinci’s bridge may end up as a garden or back yard ornament.
Basically, it is a matter of selecting the straightest treated wood posts with the fewest cracks. And once I had them, I could cut them to the desired measurements. In my case the treated wood posts are 58mm in diameter. And I cut 5 pieces of 91cm (the short horizontal pieces), and another 10 pieces of 109cm. Well, I actually cut them a little longer. Those were the final measurements after some retouching that we can see in the video.
The short pieces, I only have to sand them. But in the long pieces I have to cut three round notches. One notch at each end and a central notch at 180 degrees to the first notches. Something not too complicated to do with a drill press drilling jig and a hole saw with the same diameter as the posts (or slightly smaller). Or rather with two jigs.
Woodworking jig for drilling wooden posts on the drill press
The first drill press jig is just a simple board with one wood strip screwed on it. The function of the strip is to work as a fence to put the posts against it, and so the depth of the notches will always be the same.
This way I only have to measure how far from the end I want to drill the notch. And drill a notch in one end of all the long logs. Only in one end.
And now, to drill the other two notches in the long logs, to make the Leonardo Da Vinci’s bridge, I have to modify the jig by adding a piece of post vertically.
Like this this vertical piece of post allows to fit the notches already made and serves as a stop to drill the other notches always with the same distance between them. In the video you can watch, step by step, how to make this jig for the drill press.
Apply weather and woodworm protection and stain to the wood posts
Now, before mounting the Leonardo Da Vinci’s self-supporting bridge, I am going to sand all the logs and treat them with a stain that is also weather and woodworm protection. I know that these posts are treated wood, but extra protection won’t hurt. And besides, as they are dyed, they will also look nicer than the characteristic dirty green color that treated wood usually has.
How to assemble Leonardo da Vinci’s self-supporting bridge
And once the wood protection is dry I can mount the Leonardo Da Vinci’s bridge. At first glance this logs bridge looks like a complicated framework, but as soon as we fit the first notches we can see how this posts bridge works.
In the video you will see that this Leonardo da Vinci Bridge is quite simple to assemble. Another thing would be to make a real bridge, e.g. to cross a small river, with much larger logs. I suppose that Leonardo Da Vinci’s inventions would come with instructions for use and assembly 🙂 , like the Ikea of his time. LOL.
See also in the following video how I plan the measurements to make this self-supporting bridge. It includes how to select the treated wood posts to make this bridge, which happens to be one of Leonardo Da Vinci’s most famous inventions.
Although I would say that the Chinese knew how to make it long before Leonardo Da Vinci was born. You can also find, in this woodworking and do-it-yourself blog, how to make a fence for climbing plants with posts, including a trick for drilling the posts in the drill press.