I needed to create an adapter for a Troy-Bilt blower that I got for free and none of the existing 18V Makita adapters would work for my needs. I created a new adapter from scratch that you can use for other tool adapters.
You can get the Makita Battery Terminal from Amazon here: http://amzn.to/2dkrqeX
Instructions: Print the left and right halves. Insert the Makita battery terminal (P/N 6438386) and glue the two halves together using an appropriate adhesive.
The captive hex nuts are designed for an M5 nut.
Please see the video if you need further instructions.
Prints great with NGen. Pretty much any material would work.
For the inspiration and how I designed this.