Wanted to use my Centrotec bits with my Milwaukee Drill so I made an adapter. There are 3 parts to print. I started by printing all in PETG for testing but ultimately printed the
main adapter in stainless steel. The other 2 parts are the washer and the housing (this part) and can be plastic. One caveat to this build is that you need to sacrifice a Milwaukee 1/4" Hex Attachment for parts. I ordered a spare one off eBay so I could keep my other one intact. Once you print the main adapter part in stainless steel it will need some filing/sanding on the inside and outside to have a snug fit on the drill body.
For more info on this build check it out here: https://www.printables.com/model/280217-milwaukee-m12-installation-driver-adapter-for-cent