Skew Gear

ernest_bournine

Hi everyone, I need to design a skew gear, I have seen a few tutorials and now I can draw the sketch and extrude a simple gear, the problem is I don't know how to generate the skewness as pictured below. Thanks!

thomas_kozak

The last time I worked on something like this the general advice I got was to start with a cylinder and add a helix to the surface with the right pitch for the amount of rotation you need.  Then create a sketch/plane normal to the helix and extrude your tooth along it, merging with the original cylinder..  Then circular pattern the cylinder for the right number of teeth.

If there's a way to do an extrude/sweep with a precise rotation I would love to know about it (for instance to sweep a gear through a circle with rotation)

henry_feldman

Can you loft a surface between the 2 gear shapes with one slightly rotated? And then just match the points so it twists. I have done this to make a twisted vase, so this is just a twisted vase in the shape of a gear.

thomas_kozak

@henry_feldman that works in theory but in practice I've never gotten complex lofts to work right.

owen_sparks

A believe a loft with some guides is what you're after.

NeilCooke

I have done this - I will post the solution later

NeilCooke

Here it is - it is not perfect but close. If you want to replicate this you will need to add the FeatureScript Spur Gear example to your toolbar (press the add custom features button (+ symbol top right))

https://cad.onshape.com/documents/577bb4d1e4b022df1ab63b35/w/8b759e54235a73b8a4a7068e/e/7389dfbbdb7fcdbe7a9cf4fb