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Custom Feature: Gear Rack

imants_smidchensimants_smidchens Member Posts: 69 EDU

Realized I needed to design two gear racks for a robotics project, and rather than spend 20 minutes doing it manually, I wrote up a custom feature to automate it with some quality of life features (helical/herringbone teeth, fast regeneration, alignment stuff, blah blah blah)

Snag it here if you'd like!

image.png

100 tooth regen time

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Got me thinking that it might be interesting to try to create a rack generator that works for an arbitrary path - generating the correct involute based on the local curvature. Could lead to some neat mechanisms, lmk if that's something you'd find useful.

Cheers!

Imants

Comments

  • MichaelPascoeMichaelPascoe Member Posts: 2,744 PRO

    Cool! Ty! 😎


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  • jim_o_hernjim_o_hern Member Posts: 1 EDU
    edited December 2025

    I am struggling to figure out what is going on, This tool is incredible, when I can get it to work. However, most of the time, I select "Rack" from the FS list and I get the dialog box, but no drawing. The error message appears to indicate that it can extrude the shape because there is not a complete perimeter. I will keep trying to figure out what I am doing wrong. Again, this tool is incredible and I want to get it working for me as reliably as the Spur Gear FS does.

    FWIW: When I load your example and edit it, I can create any changes I want…and that may end up being my solution. But if I begin a new Part Studio and select the "Rack" tool, I get no drawing. The error is "Rack 1 did not generate properly. Cannot resolve entities." I get this message before I even make any changes in the dialog box.

    UPDATE: So, I have stumbled into a solution (the solution?) that may be painfully obvious to most users but was new to me. When I click the Rack tool, I then need to click on the 'origin'. At that point, the initial drawing appears and I can begin making edits. This was different from the Spur Gear feature. Now that I know, I am zooming along! Thank you again.

  • EvanReeseEvanReese Member, Mentor Posts: 2,759 PRO

    Thanks, Immants! The arbitrary curved rack is especially interesting to me. It would unlock some practical and many more really odd mechanisms.

    Evan Reese
    The Onsherpa | Reach peak Onshape productivity
    www.theonsherpa.com
  • eric_pestyeric_pesty Member, pcbaevp Posts: 2,501 PRO

    This hurts my brain, especially the eccentric hole ones!

  • EvanReeseEvanReese Member, Mentor Posts: 2,759 PRO

    Oh for sure. There are also some bicycle drives with elliptical sprockets so the mechanical advantage varies slightly with each revolution so that you can give it more juice at the strongest part of your stroke without being limited by the weakest. No idea how big of an impact that makes though.

    Evan Reese
    The Onsherpa | Reach peak Onshape productivity
    www.theonsherpa.com
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