Gear Up: A 15-Minute Intro On Involute Gears

Large gears on a bridge in Geneva, Switzerland

If you’re into CNC machining, mechanical tinkering, or just love a good engineering rabbit hole, you’re in for a treat. Substack’s [lcamtuf] has written a quick yet insightful 15-minute introduction to involute gears that’s as informative as it is accessible. You can find the full article here. Compared to Hackaday’s more in-depth exploration in their Mechanisms series over the years, this piece is a beginner-friendly gateway into the fascinating world of gear design.

Involute gears aren’t just pretty spirals. Their unique geometry minimizes friction and vibration, keeps rotational speeds steady, and ensures smooth torque transfer—no snags, no skips. As [lcamtuf] points out, the secret sauce lies in their design, which can’t be eyeballed. By simulating the meshing process between a gear and a rack (think infinite gear), you can create the smooth, rolling movement we take for granted in everything from cars to coffee grinders.

From pressure angles to undercutting woes, [lcamtuf] explores why small design tweaks matter. The pièce de résistance? Profile-shifted gears—a genius hack for stronger teeth in low-tooth-count designs.

Whether you’re into the theory behind gear ratios, or in need of a nifty tool to cut them at home, Hackaday has got you covered. Inspired?

10 thoughts on “Gear Up: A 15-Minute Intro On Involute Gears

  1. Keep in mind Lcamtuf is an ex-googler and software engineer. While his writings are probably correct, they’re not based on practice. If you need a proper reference, grab an actual textbook. “Machine Design Fundamentals” by Zbigniew Osiński is like $20 new.

    1. Keep in mind Lcamtuf is an ex-googler and software engineer.
      He is a true hacker at heart, known by everybody in software hacking scene.

      While his writings are probably correct, they’re not based on practice.
      Not based on deep machining practice, but he made a lot of gears. Probably starting with his cnc machining for moulding gears post https://lcamtuf.coredump.cx/gcnc/

  2. “Substack’s [lcamtuf]”

    That’s an odd thing to write! Substack is just the platform that lcamtuf is using, like WordPress or Medium. lcamtuf is a customer of Substack, not an employee or contractor.

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