I got tired of fumbling around under my desk to switch my audio connection between a headset and a speaker bar so I created a simple 3.5mm TRRS audio switch with KiCad and FreeCAD. 

The case was designed in FreeCAD 1.0.0. I have included the native FreeCAD file as well as STEP files. M2.5x4x3.5 threaded heat-set inserts are pressed into the front piece of the case. A vertical heat-set insert press tool makes it much easier to install all of the threaded inserts straight up and down. The back piece of the case is secured with M2.5x10 screws. The case is designed to be mounted with Kreg pocket-hole screws.

The KiCad files for the PCB can be found on GitHub. The audio_switch_gerbers.zip can be used to order the boards at any PCB fabricator. The PCB should be made 1.6mm thick to fit with the case.

Amazon affiliate links (that help support my work):

Threaded heat set inserts kit (including M2.5x4x3.5 inserts): [https://amzn.to/46FmUW0](https://amzn.to/46FmUW0) 

Vertical heat set insert press tool with tips: [https://amzn.to/4o9k2qs](https://amzn.to/4o9k2qs) 

Metric screw kit (including M2.5x12mm screws): [https://amzn.to/4pVX7jP](https://amzn.to/4pVX7jP)