I cut out he parts using a dremel and a .036 end mill although I have found the carbide router bits work just as well. Some have worried that with all the leverage it would be easy to break the bits. I don't brake bits often when cutting. When I do break them is when carelessly bumping the arm or just when finishing a cut. Taking care has eliminated that problem. I always cut out doors and set a box fan at the end of my unit to evacuate shell dust.
I like to make them fit a little loose. I really don't like having to file too much. If I made my stylus to cutter bit a little less I would get a tighter fit. I made my stylus by taking a piece of 1/4" rod and drilling a whole down the center and epoxying in a finish nail of about the right size. This unit has a 2.77 times reduction so to get a really tight fit on my parts I would have a stylus that is 2.77 times larger than the cutting bit.
Inlay with a layer of epoxy pore fill. This is my first try at engraving, a little rough but it did give me an idea of what could bee.
This is my second poormans CNC. I made a few improvements over the first by making the arms longer that hold the router and having a little less reduction over my first. This one has a reduction of 2.77. I wanted the longer arms so I could cover enough area to be able to do a custom rosette. If I were to build a third I would like a reduction of about 3.25 to 3 or so. They are pretty easy to make. I made this one in less than an hour. Moving parts are 1/4" iron wood from a piece of iron wood decking I scavanged.
Is the poor mans CNC as good as a real CNC, No, better in may ways. It's easy to take outside, cheap to make (this one only cost me some 15 cent plastic bushing a few 1/8th bolts and nuts and some scrap wood, less than $3) Your inlays don't look like they were cut on a CNC. I really don't like the CNC look. And did I mention you don't need to know a thing about CAD.
