AnyCubic Mega Zero Y-Axis Linear Rail Upgrade

This is a remix of: https://www.thingiverse.com/thing:4903945 

This remix uses only 2x MGN12H carriage blocks instead of 3 as I found 3 was difficult to get good alignment (I think my bed bracket is slightly warped). I've also modified the design to be beefier and allow the use of M4 Heatset inserts.

This mod uses 2x MGN12 with 2x MGN12H carriage blocks to replace the existing Y-Axis linear rods on the Anycubic Mega Zero. The mod reuses all existing factory M4 nuts and mount locations to preserve bed height. 

You do not need to support the MGN12 rails. They are plenty stiff. Do not attempt to use MGN9 C/H. You'll be 3mm too short in the Z direction and the MGN9 rails are not as stiff and will require support.

The mounting spacers go under the MGN12 rail mounts inside the 4020 extrusion to add additional support. 

NOTES: 

• Please use good quality knurled Heatset inserts like these.
• I recommend printing these in ABS+ (eg from eSun) for best results
• The instruction from foureight84 are essentially the same for this remix

BOM:
(20) M3x8mm Hex Cap Screws:
      (8) for MGN12 Rail Mounts
      (12) for attaching the y-carriage adapter to MGN12H blocks.
(8) M3 Nylock nuts for MGN12 Rail Mounts
(2) 400mm MGN12 Rails
(2) MGN12H Carriage Blocks
(12) M4 Brass Heatset Inserts

Reuse M4 nuts on the y-carriage and linear rod mount.

Parts to Print:
(2) Linear Rail Front Y-Axis.stl
(2) Linear Rail Back Y-Axis.stl
(1) Linear_Rail_- Left - with_Heated_Inserts.stl
(1) Linear_Rail_Right-Dual_Y-Carriage_Adapter_with_Heated_Inserts.stl
(8) Y-axis Mount Spacer v8.stl