Cable Grommet (customizable)

Customize using OpenSCAD. Just tweak the sizes as desired, press F6 and export the STL. These STLs are for a 1.25" (31mm) hole saw and a 1/2" (13mm) center bore for cabling. You might need larger or smaller of each, OpenSCAD makes that stupid easy.

Print 2 of each as the parts are meant to work with existing applications.