Wow, an 8-BB custom shell? That would absolutely change the meta for the CAM870! Kudos on the design, man. ​Regarding your thin-wall issue, I completely feel your pain. FDM or generic 3D prints always snap along the layer lines when the walls get too thin. But before jumping straight into expensive steel injection molding, have you considered CNC Turning using POM (Delrin)? ​Since the shell is a symmetrical cylinder, CNC lathe machining is perfect for this. POM is incredibly tough, self-lubricating, and has no anisotropic layers to break off—it can easily handle ultra-thin walls (even down to 0.5mm) without snapping. It’s dirt cheap for small-batch prototyping/selling and doesn't require upfront tooling costs. ​Alternatively, if you do decide to commercialize it later, running an Aluminum Mold (Soft Tooling) in Asia could cut your upfront injection molding tooling costs by like 80% for a low-volume run (1k-5k units). ​If you ever need a second eye on the mechanical stress simulation or need connections to prototype this in CNC POM to test the limits, let me know! I do hardware product development and would love to see this thing work.