While that will work to produce a rough facsimile of the things you're scanning, if you want to produce working mechanical parts, you need to start with clean geometry. A scan can give you a head-start on that by capturing points on the surface which can be used to reconstruct the "design intent" of the part, and a clean CAD file you can then print. This process is called Reverse Engineering. It requires not only a scanner but some specialized software, and a trained operator to use it - it's not going to work without some of that "user intelligence".