Anycubic Mega spool holder adapter

I'm using https://www.thingiverse.com/thing:2070272 with adapter to be installed on my Mega S
You will need:
- bearings as described on spool holder link
- M8 screw 160mm length
- 3XM8 nuts
- 2XM3X8mm screw

ring model is an adapter on the original spool with 72mm hole to be installed onto mentioned spool holder

2019-08-14 version 3 added for spool to be better aligned with printer frame (shifted left)