Remix of Belt Guard for SD4 (EZ print)

This is a remix of Tick Tock's Belt Guard for the Solidoodle 4. Modifications were done to be able to fit it without removing the existing cables and cable holders and to make it magnetically attached to the frame.

- Removed tabs that were there to hold cables
- Added holes for small round magnets (5mm diameter x 2 mm thick)
- Removed some material to fit around the existing cable ties
- Removed a corner off the side that touches the z axis rod to fit with a filament guide accessory.