safety keys
thingiverse
Here are 2 keys that I use when I work on machines. These keys will let me run and troubleshoot a machine with the doors open or off. Since they are plastic they will break easily and you don't want to leave them in the switch any longer than necessary. Safety first. Print them in bright red or yellow so they stand out.
Download Model from thingiverse
With this file you will be able to print safety keys with your 3D printer. Click on the button and save the file on your computer to work, edit or customize your design. You can also find more 3D designs for printers on safety keys.