Video Presentation

How it works

This machine is used for weighing letters or small objects, inspired by Columbus Maul scales. It rely only on mechanical components, with connecting rods, levers, dials and counterweights.

The upper tray is connected to each pendulum side with connecting rods, which share a coaxial rotation axle. When weight is applied, the two pendulum sides move apart, the greater the weight is. One pendulum side holds the cursors on it, the other holds the dials.

The bottom cursor indicates the weight from 0 to 80gr. It is placed further from the center of rotation of the two pendulum sides, and with an angle between the connecting rod and the pendulum closer to 90°, which makes the measurement more sensitive and linear.

The upper cursor displays the weight from 70 to 175gr, with the same functioning as the previous dial, but at a less distance and an acute angle between the rods and the pendulum. This causes less displacement of the cursor as the weight increases, allowing a non-linear scale and a reading of a greater weight.

This combination of functioning and dials enables a fine reading of the weight on the bottom cursor, and a rough reading of larger weights on the other cursor, with keeping the symmetry of the scale which is important for its functioning. 

If you want to read more about Letter Scale, please visit this excellent website.

How to build ?

📕 You only need the parts and the instructions. You can purchase the PDF instructions on this shop (sticker sheet to print included) and build with your own parts.

🎁 If you want to purchase the LEGO parts + PDF instructions and sticker sheet, the kit is available at Buildamoc. A perfect gift for antique objects lover or to decorate a desk.

🧩 The bill of material can be checked below in the instructions previews, or on rebrickable.

About this product

Instructions preview

After the build

Please watch this video to ensure a correct functioning / setting of the scale :