This one is for fellow machinists and engineers: a newly arrived Dixi 0.1mm end mill. The cutting blade is 100 x 100 microns or as thick as human hair.
To put it in perspective, I took a photo of it next to the finest Japanese 0.25mm pen tip, with regular ballpoint pen above them.
But this is not the scary bit: due to its size, our endmill will have to spin at 50,000 RPM at the bottom of a 700 kg spindle column travelling at the speed of 1G with sub-micron positional accuracy and to start, stop and reverse instantaneously. That spindle movement action draws 60 Amp of peak current per phase.
The equivalent of your car going from 0 to 100kms in 2.47 seconds.