Interesting how the depackaging was done - curious what the mill setup was looked like. It seems like achieving .001” on manual mills isn’t uncommon; which would be about 25 micrometers, so in line with the depth of passes that were being taken here. I can see how the magnified view of the part would be helpful.

A thou on any decent mill is no problem.

Given the teeny tiny endmill the author was using, I suspect they were using a small mill with a very fast spindle. Maybe something like a Taig or a Sherline.

Edit -- I see on another post the author has a Sherline 5400 mini mill.