This design is a micromanipulator designed to precisely handle tools at the micron scale. Micromanipulators are very important in science as they allow to interact directly with microscopic device, when direct manual handling would most likely result in destruction. However, professional quality micromanipulator can be very expensive (thousands of USD), out of reach of hobbyists and sometimes a scarce resource even for professional researchers.

This is my take at designing a high quality micromanipulator. The result is stiff, compact and moves smoothly. Not quite up to par with the commercial alternatives, but fit for most applications and accessible for a handful of USD and half an hour of your time.

The complete build process is described in detail in an instructable:
https://www.instructables.com/Build-a-3D-Printed-Micro-manipulator/

And a quick demonstration video here:
https://youtu.be/zBTdy4V52NY

I also designed a series of translation rotation stages you may be interested in:
https://www.instructables.com/Build-a-3D-Printed-Linear-Stage/
https://www.instructables.com/Build-a-3D-Printed-Goniometric-Stage-tilt-Correcti/
https://www.instructables.com/Build-a-3D-Printed-Rotational-Platform/