Negretti & Zambra Pocket Weather Forecaster

Get ready to be amazed by the incredible Negretti & Zambra forecaster! This fascinating device, which was widely used in the early 20th century, can accurately predict the weather with amazing precision. Originally designed in 1915 by two Italian instrument makers, Negretti and Zambra, this amazing instrument quickly became a must-have for sailors, farmers, and meteorologists alike. It was later renamed Zambretti forecaster. And now, with this instructable, you can build your very own version of this remarkable device!

With its ability to predict short-term weather patterns based on barometric pressure, pressure trends, and wind direction, this device is a marvel of meteorological science. By studying pressure fronts and the boundaries between high-pressure and low-pressure zones, the Negretti & Zambra forecaster can accurately predict whether you can expect sunny skies or stormy weather. And if you're a history buff, a weather enthusiast, or just curious about vintage instruments, then you're in for a real treat!

So come on, let's dive into the exciting world of the Negretti & Zambra forecaster and discover the secrets of this amazing device. With this instructable as your guide, you'll be able to create your own version of this incredible instrument and unlock the mysteries of the weather in no time! Before you do, watch the little movie about the first attempt to recreate it.

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Supplies

The original version used a transparent disk, but this special redesign cleverly uses a ring instead of a disk and can be made out of wood. It's super easy to make, and all you need is a sheet of 1.5mm basswood, wood glue, sandpaper, tape, clear coat, and most importantly, a laser cutter/engraver! And if you want to make it even better, a Dremel with a fine tip is the perfect tool.

If you don't have a laser cutter/engraver and still want to play with the device, you could just print it out, stick it on some cardboard and cut with a sharp knife.

Step 1: Disk 1 & Rosette

Let's take a closer look at how to make the front of disk 1 for your amazing wooden forecaster! First things first, make sure you have the perfect settings for super fine engraving – for my machine, the finest setting was a dot per 0.05 mm. You might want to experiment on some leftover wood to make sure everything is just right.

Now, let's get started! Mount a sheet of basswood on the laser bed and load the back image of disk 1. Set it to vector mode and scale it so it's about 70 mm wide. Remember to use the same scaling throughout the process. Engrave the disk using the finest possible setting, making note of the position on the basswood.

Next, load the cutting image for disk 1 and use the same scaling and position as for the front image. Choose a vector setting so it cuts along the edges of the black area. To avoid smudging, you can cover the disks with some thin tape before cutting, but it's not necessary. Once the disk is cut, clean the edges using sandpaper. Congratulations, you've finished the backside of the disk!

Turn it upside down and check the front for burn marks. If there are any, use sanding paper to remove them. Put the disk back into the empty space in the basswood that is ideal for positioning it. Engrave the front image. The end result of this step is disk 1 with a hole in it, and a little rosette, that fits the hole. To protect your beautiful creation, add a clear coat for some extra shine and durability.

Step 2: Disk 2 & Ring

Start by flipping over the basswood sheet and re-mounting it. This flipping makes sure you get the same side of the material on the front. Then carefully engrave the image for disk 2 on the sheet, ensuring that the scaling factor matches the first step. Cover the result with thin tape and use the cutting image to cut around the edges. Take it out of the lasercutter, but leave the tape on the disk. Add a piece of double sided tape to it, and attach it to something that you can hold. like a piece of wood. Use this and some sanding paper to remove a thin layer (0.2mm) of the backside of the disk and ring. You'll be amazed at how quickly you'll reach the 0.2mm mark! This will make it easier for the disk to rotate. Once finished, remove the tape and clean the edges. Voila! You now have a ring with a barometer scale and a coding disk with letters and a hole through it. Add some clear coat to protect the wood and you're all set to show off your new creation!

Step 3: Disk 3

Get ready to take your project through the next step! Follow the same procedure used for disk 1 to engrave disk 2, making sure to use the same scaling factor and engraving the image of disk 3. Cover it with thin tape and cut it using the cutting image.

But here's a fun tip - why not slant the edges of the three holes? This wasn't originally done, but it can really enhance the readability of the code letters in two ways. First, more light will shine onto the letters through the small holes. Secondly, you'll be able to read it even while holding it at a slight angle. Trust me, I learned this the hard way with my first iteration which was hard to read. While it's not necessary, I highly recommend slanting the edges. You can use a very fine file, but I found it easier to use a Dremel with a fine tip. And don't forget to apply a layer of clear coat to protect your creation!

Step 4: Axis

This step is a piece of cake! Simply load the image, use the same scaling factor as in step 1 to scale it, and cut away. That's it!

Step 5: Mount Axis and Rosette

Use some wood glue to connect the axis to the rosette. Clamp them together and let them dry for two hours.

Step 6: Mount Disk1 and Code Disk

Let's get that code disk mounted onto the front of disk 1! Mount the code disk to the front of disk 1 using some wood glue. Take note of the tiny marks at the three o'clock position in the picture to ensure proper orientation. Check the back to make sure it's nicely centered and remove any excess glue. Clamp the parts together and let them dry for two hours. Then, get ready to bring it all together in the next step!

Step 7: Final Mounting

Now that the glue from steps 5 and 6 is dried, it's time to bring this baby to life! First, put the ring around the code disk and make sure it rotates freely. Then, insert the rosette with axis from the back and use some wood glue to mount disk 3 to the axis. Be sure it's centered! Hold it between your thumb and index finger and rotate it around, but keep rotating to prevent any excess glue from sticking to the other disks. After a couple of minutes, release your grip and clamp the device together, then let it dry for 2 hours.

Step 8: Start Using Your Forecaster

Congratulations, you have now completed the construction of your very own wooden Negretty & Zambra forecaster. This project not only gave you a beautiful and functional piece, but also allowed you to enhance your skills in laser cutting.