Aluminum CNC Part STP Model

About the project

I have a simple rectangular block that needs to be milled from 6061-T6 aluminum, and I need a clean, ready-to-machine 3D file in .stp format so I can drop it straight into my CAM package. The blank size is 5.000" × 2.000" × 2.000". Along its 5-inch length the top face must become a true cylindrical surface with a 333.335 in radius. Across the 2-inch width that surface stays perfectly flat—no crown—so the cylinder runs only lengthwise. That geometry should produce a sagitta of roughly 0.0094 in at mid-span. Dimensional accuracy is critical: please hold ±0.001 in on all three overall dimensions and keep the cylindrical profile within the same tolerance. The model should reflect a smooth machined finish; I’m targeting 32 µin Ra or better and will handle the tooling strategy myself once the solid model is correct. Deliverable • One native .stp file representing the finished part, fully constrained and ready for CNC programming. I’ll review the file by overlaying it on my spec and checking the radius, sagitta and corner stock removal, so make sure the surface reads as a true analytic cylinder, not an approximated spline. Let me know if you need any more numbers before you start.

Skills required