August 1, 2026
Gear drama with extra teen torque
Show HN: I'm a 15 Year Old Wannabe Engineer, This Is a Cycloidal Gearbox I Built
Teen builds a tiny power machine and the internet instantly adopts him
TLDR: A 15-year-old built a working homemade gearbox with a 3D printer and his own code, and the community was seriously impressed. Most comments crowned him a real engineer on the spot, while a few added classic internet spice with privacy warnings and an AI jab.
A 15-year-old showed off a homemade gearbox — basically a compact part that helps a motor turn with more force — and Hacker News immediately turned into equal parts proud parent convention, safety lecture, and mini culture war. The project itself is genuinely impressive: after two earlier attempts, including one that failed because the parts were too tiny and fussy for a home 3D printer, the teen finally got Version 3 working with a small motor. He even wrote his own Python script to generate the design, which is the sort of detail that makes engineers start nodding like they’ve just seen the chosen one.
But the real fireworks were in the comments. One camp was pure wholesome hype: “you’re not a wannabe! you’re an engineer!” was the dominant mood, with others basically saying, “I don’t even know what this thing is, but wow.” That reaction matters because cycloidal gearboxes are obscure enough that most readers needed a translation just to understand why this was cool — and they still came away impressed.
Then came the tiny splash of drama. One commenter dropped a blunt warning: don’t post your age on the internet, instantly giving the thread a protective-parent energy. Another tossed in the spiciest jab of all, telling the teen to “try making something without AI too,” which felt like the classic internet move of finding a way to start a debate even under an undeniably clever homemade machine. In the end, the thread’s verdict was loud and clear: the kid came in calling himself a wannabe, and the crowd basically said, absolutely not, you built the real thing.
Key Points
- •The article describes three gearbox iterations, with the third version becoming the first functional NEMA 17-driven cycloidal gearbox after an unsuccessful compact second version.
- •A Python script was created to generate the cycloidal drive geometry using parametric equations based on a SolidWorks reference article.
- •The script is run through Fusion 360 using its Scripts and Add-Ins workflow after cloning the repository and selecting the cycloidal_generator folder.
- •Version 3 has a 1:9 ratio with 10 outer pins and 9 rotor lobes, a 90 mm outer diameter, and is built from PLA with specified screws and bearings.
- •Reported Version 3 performance includes 1.28 N·m ± 0.0061 N·m output torque, 66% ± 0.220% efficiency, and suggested hardware upgrades for higher rigidity and lower friction.