Part Design – Additive Helix

Making threads or cutting threads just got a lot easier with Additive and Subtractive Helix in the Part Design Workbench. This tool adds the ability to easily sweep a sketch along a helix. With a sketch selected the tool adds the Helix and presents an easy to use dialog to modify the Helix.

The Additive Helix will take a profile and sweep it along the entirety of a configurable Helix.

FreeCD Version ( for this article )

Version: 0.19.
Build type: Release
Release Date: 2021/2/11

To activate the Additive Helix SELECT an appropriate profile.

The profile needs to be a completed shape. For example a rectangle where all four corners are connected. If the shape has an opening the tool will not work. I used a rectangular sketch on the XY Plane to make the Artwork fo this post

The Swept Helix will be from the Z axis of the Sketch, listed as “Vertical sketch axis in the “Helix Parameters” Dialog

The default sweep shows the above sketch shows as follows

Orienting your Swept-Sketch can significantly aide in the final placement of the Swept-Helix

For example if you are looking for a “thread” that is oriented along the Documents Z-Axis you can map you sketch on the XZ-Plane of the document.

Pitch-Height Mode

The default mode lets you determine the “Height” of the Helix, or the length the threading will run, if you are doing threading.

The pitch will determine the distance around the diameter each segment will travel before completing a full turn. It is measured from the “bottom” of the start to the “bottom” of the finish.

Pitch-Turns Mode

Instead of determining the length of the Helix by height this mode uses the number of turns along with the pitch to calculate the overall length. This might be perfect for modeling wire windings.

Height-Turns Mode

The final mode sweeps the Helix the given number of turns inside the described height.

This first example shows 1 turn over the height of 20mm

While the second example shows 4 turns over the height of 20mm.

Conical Threading

One final option of note is the ability to place the threading , or any swept shape, along a conical helix. This can be achieved by selecting the slope angle of the helix.

Leave a Reply