Re: First Time CNC Build
Given your stated mix of materials, I assume that you are doing jewelry or other artwork and for the most part very light duty use. If you are not in a hurry you might get away with a light duty table top router/engraver type machine that you describe. You would be using tiny tool bits, most likely diamond bits in the pearl and opal, and taking light cuts in the harder materials. Cutting too slow causes stainless to work harden and destroys tool bits pretty quickly, so you have to find the sweet spot for the machine, material, and tool bits. Not sure if titanium work hardens, but it's tough material to work with.
Any serious work in stainless or titanium requires a real metal cutting milling machine. A completely different machine from what you described.
Jim Dawson
Sandy, Oregon, USA