RAMPS 1.4 case holder for K8200/3Drag
In case your original 3Drag controller breaks or you just need more IO and do not want to directly solder at the SMD controller you want a fifth stepper controlled, then there is a MEGA/RAMPS combination probably your choice.
There are dozens of good cases on thingiverse. I've chosen this one: http://www.thingiverse.com/thing:639951 and here are the brackets to mount that case on the 3Drag/K8200 frame.
The mountings might look strange, but I had M516 in my spare box, so I made it fit for those screws. If you want to use M510, that is fine as well, you just need to drill for the screw head.