I have seen several of these on Thingiverse, but for some reason, the thing files were all oriented horizontally. That meant supports to build it. This version I designed in about 5 minutes in RhinoCad 5. I have a big thumb, so it is large on top. I also included several pictures of my actual printed part in service. I designed it so no supports are needed to print it. OK? It's just another thumb knob for the A8, but I have proven it works and have photos to prove it. Enjoy! (By the way, not slamming any of the others who have made one of these for this printer, just saying, I do not know how to re-orient an stl file in my slicer (Simplify 3D - which I paid for and LOVE!). And I don't like cleaning out supports. My Anet A8 prints GREAT with my newly attached BLTouch auto leveling Bed sensor. See the specifics below for details on my settings using Simplify 3D.

I have included the Rhino .3dm file if you want to modify it.