(The second photo is just an example, a coaster inspired by Westworld's labirint.)
This is an upgrade I made some time ago for my Anet A8, It replaces the fan holder, it needs some edits, with two little magnets on top it can hold the fan, glued with the heatsink in place, giving easy access to the extruder gear.
The front part needs 3 bolt and nuts (you'll probably have some of them spared from the printer building parts).
To use the mill you won't need to unscrew anything, just mount the extention of the dremel and you're ready to go!
This is the software that i use to slice, you'll have to manually edit the commands and manually reset the starting point of your printer, it's a little bit of work but the payoff is huge!
For where to find the 3D printer and the Dremel I designed this project around browse to my page: https://www.thingiverse.com/FenriX
Using the dremel flexible extension you will keep the frame of your printer light, the pressure you put on the z axes will be reduced by a fair amount, just beware that this dremel is a really cheap solution, as the printer itself is not designed to perform such a task.
With this in mind try it with easy to mill materials, don't overdue it!
This is though, in my opinion, a great solution if you want to try out what a CNC works like without spending lot's of money!