Greenboy 3D sells 3d-printer pellet extruders. He provides models for all necessary toolhead components, and instructions for printing. But I wanted to model a new toolhead specicially for my Voron 0. In the process I've made a couple of .step files for the hotend, and the whole motor-gear-hotend assembly.
This isn't meant to be precise enough to manufacture components directly. Rather it is just meant provide some relative sizes and positions. In particular, I modeled the pellet screw as an ordinary thread, rather than the tapered thread used by the actual pellet extruder. This was done to give me some general visual representation of a screw, but really even what the screw looks like in reality.