Back when I was learning to fly, I did most of my landings on our 200 foot wide runway. I was all over the place. Never down the center line. Then the instructor took me up the valley to Vernon. 35 foot wide runway. I had no problem keeping it right down the line. After that, I told myself that I only had the painted lines down the center to land on . No more problem.
All that to illustrate this: When we are faced with working to a tighter standard, we can very often hit it. Sometimes the first time, sometimes after a remake or two. Having a specific measurement to machine may seem daunting, but if you just take it slowly and feed in a few thou at a time, then check, check, check, you will find that you can do it. And you'll grow by it.
This will be a great project for all of us.