It's called gun drilling and about all I know about it is what the rep at IMTS told me when I looked up and saw a 3/8ths drill bit whose business end was eight feet above me. The "gun drilling pavilion" was not huge? But it was not small either. I'll bet you can do a 1mm hole 40mm deep (I've been doing enough metric that I'm starting to think in it!) but not without planning and tooling up. Now I'm really curious as to what that hole was for... I learned engineering fundamentals by taking apart cars from the age of 6 so underneath all the theory is a Cargo Cult understanding of mechanical objects. "I have never seen that hole, therefore it is impossible" without ever learning any 10x rules.
I've harped on this before - we see 3d through the way things move as we move our head, not through stereoscopic vision. Stereoscopic vision really only carries out to things about 6 feet away. When we're looking at a monitor, the image doesn't move - but with my magic puck I can move things around exactly as I want them whenever I want them and my brain builds 3d. Usually you hold down the center button but I found that limiting, so I bought a puck. Jeron Lanier made the point that humans adapt to any control schema really quickly; for my brain, "twitch my fingers" easily substitutes for "move my head."
This is all for jewelry making, but those jewels will run towards watches, pens and accessories. At a certain point, any precision assembly or surface needs to be machined rather than filed or cast or sawed or whatever. I got to the point with the casting where I went "and nothing will go together without things being precision drilled" at which point the question became "so how are you going to do that."
This machine cost me about $9k for the husk. It's been about another $15k for parts (fully $7k of that was rebuilding the spindle - yeowtch!). It will, if things go to plan, perform about as well as this thing, which I was quoted $180k for. It will also have a working envelope easily 3x as big in every direction. And, because I am controlling it with a highly-configurable Windows-based CNC interpreter, I will be able to do obnoxious things like configure it as a 5-axis drag knife, which is a device that no one in the world has ever made.