MGN12H Upgrade Kit for D-Bot

MGN12H upgrade kit for D-Bot. Its use standart parts.

Bottom wheel is 21mm
(https://ru.aliexpress.com/item/Micromake-3D-Printer-Parts-9pcs-lot-DIY-Black-Pulley-Parts-Pulley-Wheel-New-Injected-Plastic-Wheel/32774425400.html?spm=2114.13010608.0.0.uAIy92)

Update 06.04.2017
- Add 8.5mm wheel spacer

!!! Under desing yet !!!