I see no reason to have the main board stuffed under the machine, so I decided if I was going to do this main board upgrade, that I would also move the main board out and make an enclosure that will completely surround the board. This will make the board and wiring much easier to access and service as needed. I took Teaching Tech's Idea to higher level and this will accomplish my goal. I was always frustrated by the lack of access to the main board, This gives me the opportunity to fix two problems at the same time. This is 3 pieces, a mount that slides into the 4040 rail, the main case and the cover. This is a work in progress, so the files can change. These files are the ones used to print the items in the picture. The new MKS Gen L board is on the way, so this is not a complete installation. Added file to include a version of the box with 4 - 4mm mounting holes on the back. 01/12/2019 11:55 CST: I have modified the Case. Cover and Mounting Bracket files with various changes to improve durability, reduce material use or provide better wire access. These are small changes, which are reflected in the latest files. Final Version printed and mounted, waiting on the new motherboard.
Amazon Basics PLA/PETG
I did the main box in PLA, the Mounting Base and Box Cover in PETG. I was mainly using up some short runs of filament that were left over from other prints. These can be printed in your favorite filament. I used supports on these parts, the supports were very small. The box has wire pass holes in the back and bottom, I hope that I have allowed enough holes for all the wires. Wires will be transferred and arranged as needed when the new board arrives. The base slips into the side of the Left frame rail, it is a tight fit. The Main box secures to the base with M2 x 10 screws and washers. I opted for a fan cover to match my hot end cooler fan. Obviously the fan can mount as a push or pull fan. The fan cover file is included, it is PETG as well.