For my school microscopes we were not able to move around the slides, which for applications like looking at water organisms could be useful. I made the model fully from black PLA, but i might make new models from PETG. Initially the design i took from thingiverse, did not fit very well. The part that attaches to the base of the stage was too long. This part might need to be longer or smaller based on what microscope table you have. I have microscope stages that have a thickness of 12 mm's. Some of the items will be needed to be print with supports. 

The longer (plastic) screw was too thick initially which caused it to not fit within the other parts well. Additional items you will need are.

• A small screw 
• A tiny spring (i used springs from a ballpoint pen which fit perfectly).
• Some hard plastic glue

You need the glue to connect the right hook to the bar. You also connect the connector to the bar using glue as seen in photo 4, and you clamp the left hook by using a string.