Cruller Threads - A Custom Thread Profile

This is an exceptionally WIP project meant to gather feedback, please don't attempt to use this as a finished product. 

Updates:

• 2024/07/23: Changed the M51+ sizes to now have 1-20mm pitch options instead of 5-20mm.

If you decide to try using this profile, please provide feedback on your experience.

Most thread profiles built into CAD packages aren't optimized for printing, live-editing them is a pain, and sweeping a profile for a custom thread takes time/effort. Enter Cruller threads. 

Pastry is the name, but a simple, optimized thread profile is the game. Cruller includes the following:

• 110° root angle - This gives a 55° overhang that should manageable by even the most clapped out Ender.
• .25 ratio truncation - Based on the pre-truncation thread depth, this gives them a clean trapezoidal form to eliminate weaker thin sections that often break or cause fitment issues. It also means a larger thread can fit into a smaller area than longer/pointier forms.
• Metric, Major Diameter sizing M4-M200 - M10 means a 10mm (before any clearance) major diameter, M50 means 50mm, etc, simple and easy to understand.
• Variable pitches - M4-M9: 1-5mm pitches in .5mm increments, M10-M50: 1-10mm/1mm, M51-M200: 1-20mm/1mm.
• Range of clearances classes -  0-0.5mm clearances in 0.1mm increments.

Together, I'm hoping the Cruller featureset provides enough benefit that the type of designer to consider sweeping their own threads would feel comfortable using this as a more standardized solution. 

PRINT FILES

Because Printables wants print files, and just as a good starting point for initially appraising the profile, I've included a set of pieces with M10x2 internal and external threading in the full 0-0.5mm sweep of clearances. I recommend starting with the 01 version of both to see how your printer handles it, then moving looser by 1 increment on 1 piece at a time, ie trying external_02 with your internal_01. The pieces have their clearance values marked on them to help keep track. 

OTHER FILES

Because Printables doesn't support .xml, I've shoved the file into a zip. Normally, you'd need to extract this to %user%\AppData\Local\Autodesk\webdeploy\production\*LATEST*\Fusion\Server\Fusion\Configuration\ThreadData\, where LATEST is the most recent folder, and then it would show up within the thread tool in Fusion.

I recommend, instead of that, installing the Fusion addon ThreadKeeper, following its information to use a custom folder to store user threads (probably somewhere handy near your other CAD files), then placing the profile there and syncing it from the addon. This makes things much simpler and helps when a Fusion version update moves the thread folder but not custom profiles.

OTHER NOTES

This profile is currently only for Fusion because that's what I have templates for. Should you desire to use it for other CAD packages, let me know and get me access to a template to use and I can probably port it over.