Sep 272020

Version 2.0 of my online involute spur builder is available now: Online Involute Spur Gear Builder v2. It is a complete rewrite of version 1 which was introduced 2014 (part1, part 2).

Version 2 creates higher quality output without ragged edges at higher speed. Like before, undercuts as needed for small tooth counts are correctly handled; clearance, backlash, and profile shift are fully supported.

As an extreme case the image on the left shows a 12 tooth gear meshing with a 5 tooth pinion (tool link). Notice the extent of the undercut. The image on the right (tool link) shows the same gears but this time with profile shift applied. The profile shift considerably strengthens the pinion gear teeth.

Without profile shift Involute gears with undercut and profile shift.

The key differences of v2 compared to v1 are:

  • Modern SVG output
  • Higher quality output (no ragged edges) without excessive segment counts. No more need to fiddle with quality parameters.
  • Significantly faster than v1 at any acceptable quality levels
  • Parameters are automatically injected in the URL; i.e., the URL fully specifies the output and can be shared with others.
  • Corrected internal gear generation (e.g., clearance is properly applied)

In case you are interested in how the gear shapes are created, the first post that introduced version 1 is a good start. Then this pdf document provides more detail about how v2 accomplishes the smooth curves that v1 struggled with. Internal gears are particularly challenging in this regard. Here is just a teaser:

Internal Gear Shape Creation

  6 Responses to “Online Involute Spur Gear Builder v2”

  1. […] UPDATE: This post refers to an old version. For information about version 2 see this post. […]

  2. […] UPDATE: This post refers to an old version. For information about version 2 see this post. […]

  3. Thank you for developing such a useful tool , I have used it to design spur gears for 3D printing. I have found that it produces an error where the undercut meets the dedendum circle – not a major issue and easy to work around in my CAD package. If you’d like me to email you details/screenshots please do let me know?

    Thanks again, Chris

    • Chris, thank you very much for the screenshots that you emailed me. The undercut meeting the dedendum cycle does not exist in the svg output which uses circles and arcs. It was introduced in the conversion from svg to dxf that you used (dxf breaks up circles and arcs into line segments).

      However, the other problem that you exposed (small section of the gear path reversing direction before continuing again in the right direction) was a bug in my tool. I just published an update that fixes this.

      Thanks again!

  4. What a super generator, thanks so much – it certainly solved the issue of compatibility between Mac OS and Windows. One nice to have would be the option of ‘Spokes’ – is there any chance?

    Thanks again!

    • Thank you for the kind words. Sorry, but I don’t intend to add support for spokes. There are just too many possible options. But more importantly, creating custom spokes it easily done in either CAD programs or vector graphics programs after importing the generated svg output. As a concrete example, the free open source Inkscape software is a very powerful tool specifically for editing svg.

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