Online Involute Spur Gear Builder v2

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

10 thoughts on “Online Involute Spur Gear Builder v2”

  1. 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

    1. 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!

  2. 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!

    1. 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.

  3. Thanks for an excellent gear generator, you must have put a lot of effort into it. I am trying to generate some gears with a pressure angle of 14.5 degrees.To check the results I have created a rack which should have the flank angle equal t o the pressure angle. When I input 14.5 degrees, I get a rack angle of approximately 14.06 degrees. When I input 15 degrees I get a result very close to 14.5 degrees. Is this an issue with conversion from SVG to DXF via Inkscape? If so, would it be possible for you to output DXF format data? Thanks again for a powerful, easy to use tool.

    1. Hi Jack, thanks for your feedback. You discovered a bug in my code. Thanks to your detailed description I was able to quickly find and fix it. It affected all three modes (regular gear, internal gear, and rack). The fixed version is now live. Please try again.

      1. Hi Rainer. Superb!. Autocad now reports 14.50000382 degrees for the 14.5 degree pressure angle. I think that is close enough!! 😉 Thank you for the prompt reply and rapid update. I’m planning to 3D print some unusual ratio change gears for my Myford lathe and now I’m sure they will mesh well with the existing originals. Thanks again for a well thought out tool. Cheers.

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