Pin back
thingiverse
I managed to salvage my project by finding a solution in Fusion 360 within just a few minutes. The tapered design inside allows for a secure fit, and printing two took only 2 minutes. You might need to adjust the scale based on the size of your pin. I'll share some photos soon.
Download Model from thingiverse
With this file you will be able to print Pin back 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 Pin back.