I like these “cheap” USB microscopes as they are very useful to investigate problems on PCB's.
However, the stand that comes with these microscopes is crap.

I made this vertical adjustable stand for one of these USB microscopes
that makes it much easier to get a clear focus and a stable image, even
at the mx magnification of 500x.

 This design works with generic digital microscopes you can find on
- AliExpress 
- Amazon 
- CircuitRocks 
- Alibaba 
 

If you experience problems with the threads moving badly, try to print the vertical adjust and the microscope slide with .12mm to get a smoother thread.

 Assembly is quite simple, just
slide the parts together, fix it with 3 short (max 5 mm) small
self-tapping screws and clip the camera into the holder.