18mm Male to 14mm Female Adapter

thingiverse

I'll edit, test print, and upload later. This adapter makes it possible to place 14mm bowls in 18mm holes with ease. To get the best results, heat up the part using a lighter or similar tool before pressing it between the 18mm female end and the 14mm bowl. Make sure they fit together perfectly, creating a nice seal. Allow the parts to cool down like this, and they should work flawlessly every time. No supports are necessary for this design.