Convert STL Parts to STEP

I have a collection of mechanical part files that currently exist only as mesh-based STLs. Several of the parts interact with one another—gears, hinges and other simple joints—so the final CAD must respect those moving relationships. Each part sits in the “moderate” complexity range: nothing organic or wildly intricate, but definitely more than simple blocks.

What I need from you is a clean, fully editable CAD model for every piece, supplied in .STEP/.STP format. This means rebuilding the geometry as true solids with recognisable features (extrudes, revolves, fillets, threads where applicable), rather than just wrapping the mesh. Mating faces and clearances should match the original assemblies so everything still articulates once imported into SolidWorks, Fusion 360 or similar environments.

Deliverables
• Individual part files in .STEP/.STP
• An assembly file, if the original shows multiple mated components
• All features organised logically in the model tree so future edits are painless

I will provide the source STLs as soon as we start. If any surfaces are distorted or incomplete, feel free to flag them and we can decide on an acceptable tweak before you proceed.