For one of my recent projects: Building a frankenstein camera, I needed a custom thread in Fusion 360. Creating a standard thread is straightforward: select the cylindrical face, go to Create → Thread, choose the desired thread standard and size, and you're done.
But what if the thread size you need isn't available? In that case, you'll have to model the thread manually:
- Create a cylinder with the desired major diameter.
- Go to Create → Spiral.
- Select the cylinder's axis.
- Set Type = Pitch & Revolutions.
- Enter the Pitch (the distance between thread turns).
- Set the Revolutions to match the desired thread length.
- Choose the correct Handedness (right- or left-hand).
- Sketch the thread profile (e.g. Whitworth, ISO, ACME) on a plane at the start of the spiral.
- Use Create → Sweep.
- Select the thread profile as the Profile and the spiral as the Path.
- Set the operation to Cut for an internal thread or Join for an external thread.
This method gives you complete control over the thread geometry and lets you create virtually any thread.
Adding a Custom Thread to the Thread Tool
If your goal is simply to make your custom thread appear in Fusion 360's Thread dialog, there's a much easier solution: create your own thread definition XML file.
On Windows, navigate to:
%LOCALAPPDATA%\Autodesk\webdeploy\Production\<VersionID>\Fusion\Server\Fusion\Configuration\ThreadDataFusion keeps multiple VersionID folders, so you'll likely find several directories inside the Production folder. If you're unsure which one is currently being used, simply try the newest folder first. If your custom thread doesn't appear after restarting the thread tool, try another VersionID folder.
Create a new XML file in the ThreadData directory (or copy an existing thread definition and modify it). You can then define your custom thread using the following parameters:
XML Parameters
The following table explains every XML element used in the custom thread definition.
XML Tag | Description | Example |
|---|---|---|
| Root element containing one complete thread standard. |
|
| Display name of the thread family shown in Fusion 360. |
|
| Alternative display name. Usually identical to |
|
| Unit used for all dimensions in the file. Typically |
|
| Included flank angle of the thread profile in degrees. |
|
| Defines the geometric thread profile. Common values are: |
|
| Determines the order in which the thread family appears in Fusion 360's thread list. Lower numbers appear first. |
|
| Groups all variants for one nominal thread diameter. |
|
| Nominal major diameter of the thread. |
|
| Groups all pitches and tolerance classes for one thread size. | — |
| Name shown in the Thread dialog. |
|
| Custom Thread Designation. Usually the standard designation shown in Fusion. |
|
| Distance between adjacent thread peaks. |
|
| Defines one specific thread variant (internal/external + tolerance class). | — |
| Specifies whether the thread is external or internal. |
|
| Tolerance or clearance class. This can represent a manufacturing tolerance or, as in this example, an additional print clearance. |
|
| Major (outside) diameter of the thread. |
|
| Pitch diameter of the thread. |
|
| Minor (root) diameter of the thread. |
|
| Recommended tap drill diameter for internal threads. This field is only used for internal threads. |
|
<?xml version="1.0" encoding="UTF-8"?>
<ThreadType>
<Name>CameraProfiles (Whitworth Mounts)</Name>
<CustomName>CameraProfiles (Whitworth Mounts)</CustomName>After saving the file, restart your thread tool inside Fusion 360. Your custom thread should now appear alongside the built-in thread standards in the Thread tool.
Note: Every time Fusion 360 updates, it installs a new VersionID folder. Your custom XML files are not copied automatically, so you'll need to copy them into the new
ThreadDatadirectory after each update.
