Slide Rule (Logarithmic Ruler)

Bring a piece of mathematical history to your desk! Long before electronic calculators and computers, engineers and scientists used the slide rule to design everything from bridges to the Apollo rockets.

This 3D-printable model uses a sliding mechanism based on logarithmic scales to perform multiplication and division. It’s a fantastic educational tool, a great conversation starter, and a fun puzzle for your brain.

🧮 How to Use It (Multiplication Example)

Using a slide rule is simple once you get the hang of it:

1. Find your first number on the stationary outer scale.

2. Align the beginning "1" (the index) of the sliding inner scale with that number.

3. Look for your second number on the sliding scale.

4. Read the final result directly opposite it on the outer scale.

💡 Want to dive deeper into the history and advanced functions (like division or square roots)? Check out the full guide on Wikipedia.