Surgical Drill STL-to-STEP Conversion

I have an existing surgical drill device captured only as a high-resolution STL mesh. I now need a clean, fully watertight solid model in STEP format so the part can move straight into CNC machining and other manufacturing workflows. The job calls for reverse-engineering the mesh into a parametric solid: surfaces must be healed, all voids closed, and critical geometric details preserved exactly as they appear in the STL. Wall thicknesses, hole diameters, and mating faces have to remain within typical medical-grade tolerances so that downstream suppliers can rely on the file without additional touch-ups. Preferred tools are SolidWorks, Siemens NX, Fusion 360, or comparable CAD software capable of producing STEP AP214/AP242 output; feel free to use mesh repair utilities like Geomagic or MeshLab during the cleanup phase. Deliverables • One .STEP file representing the complete drill body as a single solid • A brief report (PDF or DOCX) noting any assumptions, dimension checks, and validation screenshots comparing STL vs. STEP I will supply the original STL immediately on project start and can answer dimension-critical questions along the way. Looking forward to a precise, manufacture-ready model.