Doing a G5 Mac Pro conversion and needed to be able to fit a standard C14 panel mount power plug socket such as 
https://www.amazon.com/Panel-Adapter-Connector-Socket-MXR/dp/B07DCXKNXQ

Into the C19 socket left behind after pulling out the OEM PSU.

This is friction fit. I used a bit of JB weld to hold everything in place. this could have been closer to the frame. I released it as full creative commons, modify to your heart's content.