This is a remake of an old fidget toy I saw as a kid called the BS grinder. I enjoyed it then, and even more now. I just learned that this is a take on the “Trammel of Archimedes”. This is a pretty easy print (must be if I made one), as I am brand new to 3D printing and fine tuning the various settings. I ended up making all the parts from PETG, and they work great. I originally had trouble with the main body lifting while printing with PLA and as is in the model. I switched to PETG, added support discs and a draft shield, and that worked. I'm sure more experienced makers can tweak it further or differently. The STL file for the body needs to be printed with the grooves down, on the platform. The slides and handle printed with the posts on top. Also, the handle needs a support disc, or brim, to help adhering to the work surface. The two 3mf files have those settings done. I used .15 layer height for all, used 25% fill for the body and 15% for the others, with 2 perimeters on all. 

For assembly, press the handle into the arm (long end, grooves facing up) on a hard surface, then insert the slides into the body and then snap the arm onto both slides at the same time. The designed clearances should work fine, however I did have to touch the beveled edges of the slides with a small file to make them slide freely.

I've updated the base file, adding some relief to slightly reduce mass and potential shrinkage. And, it looks little cooler. I was able to print the purple base (updated) with PLA, just fine without the discs or draft shield. However, the arm should be printed in either ASA or PETG, as the PLA is a bit too brittle.

Please print and post your results, or any questions or comments! Thank you.