Pulley STL-to-STEP Conversion Fix

I have two pulley models that are currently only available as STL meshes. I need each one converted into a clean, fully-solid STEP file that imports into any mainstream CAD package without errors. During... (Budget: $10 - $30 USD, Jobs: 3D CAD, 3D Design, 3D Modelling, 3D Printing, AutoCAD, CAD/CAM, Mechanical Engineering, Solidworks)