I printed these adapter mounts out of Nylon but they are designed to be beefy enough to print out of anything. They are designed around holding a Dremel pen flex attachment. That keeps the weight on the print head low. I have had good success even using an Ender 2 and have cut foam board, peg board, and even G10.
I am using a 3.2mm single flute upcut endmill.
These part can print without support but the countersunk holes get a little messy. You can add support for the inside of the holes if you would like.