M3 Nylock Thumb Nut

I use these as the build platform leveling knobs on my bot. The corners are rounded off so it doesn't tear up you fingertips when turning them. The bottom has a large surface area for added contact.

File designed with ABS shrinkage in mind. Prints in ABS directly for nice snug fit on a standard M3 nylock nut from Home Depot or Lowe's.