Anycubic i3 Mega S UNIVERSAL FILAMENT SPOOL HOLDER Adapter

This design still uses the 2 608 bearings, but instead of an M8 rod, it is 3D printed and uses 2 M3 10mm screws. 

This is designed for the short version and 1 kg Spools are no problem.

You need:

2 M3 10mm countersunk screw

2 M3 nuts

2 608 bearings

2 M3 washer

1 spoolholder_short

1 spoolholder_nut

1 holder

2 halfrod

1 endcap

A vice might help to put it all together