Ender-3 V3 Plus and non-Plus - X axis carriage for Coprint Chromahead with near full brass inserters

I liked the original project and I thank its original creator for this.

What this stl gives:
1) Weight reduction:
Original carriage weight following the CoPrint tutorial: 169 g
This carriage weight: 120g
2) Build plate area back to normal:
Original build plate area with stock Chromahead: 280x285 mm for the Plus
Buil plate area with this carriage: 300x300 mm guaranteed for the Plus. (220x220 for non-Plus Ender)
(I've managed to achieve 301x308 mm with correct calibration, THREADED version).

This project has two variants:
The difference lies in the belt attachment. One is for M3 screws screwed directly into the plastic (there was too little room to add inserts), and the other version is for M3 threaded rods.
You can choose which version you prefer; neither is better than the other; they each have their pros and cons.
I also give you all the stl that you need to assemble the carriage (spring tensioner, locking plate, backing plate modified for M3 inserter).

M3 SCREWS version:
+ faster to assemble
- the screws are screwed into the plastic, which has strength limitations

M3 THREADED rods version:
+ incredibly stronger, compresses the carriage and significantly increases its tensile strength along the X-axis (if you place the threaded rods perpendicular to the layers, which I recommend for ease of printing and greater overall strength).
- you need M3 threaded rods and a Dremel or other tool to cut them to the right length.
- It decreases the maximum you can reach in the X-axis by 1 mm (with this version, I managed to get a print bed of 301 X - 308 Y printable area).

Material required:
-  11 x M3 inserter: 4 M3x6x5 front (the face you see); 7 M3x4x4 others holes (4 carriage, 3 backing plate)
- 2 x M4x8x6 (or even shorter if you don't have them), these are for securing the lower linear ball bearing.
- 4 x M3 30 mm screws for the belt attachment. SCREW version only
- 150 mm threaded rod to be cut, 4 washers and 4 nuts. THREADED version only.

Suggestions:
-To cut the threaded rods to the right length, I recommend screwing the threaded rods into the carriage, temporarily attaching the belt retainer, securing them with washers and nuts on both sides, and then using the Dreamel to trim the excess threaded rod until it is flush with the nuts, as shown in the photos. Then remove the belt retainers, install the carriage in the printer, and reassemble everything. I recommend cutting the threaded rods with the Dreamel before installing the carriage in the printer to avoid damaging it with the Dreamel.

Recommendations:
-After assembling the chromahead with this carriage, move it by hand and check that it correctly touches the Z and X sensor buttons at the top left and that the "8 in 1" does NOT touch the printer frame.

IMPORTANT Requirements:
-This carriage moves the chromahead to the right (-X) and back (+Y) to regain the space that was lost on the plate. To do this, the 8-1 is closer to the CX-1 extruders so they will have to be moved back. If you have not mounted them above the Ender frame, no problem. If you have mounted them above as per the Co-Print tutorial, it is not suitable and you will have to move them. I recommend this other STL of mine specifically designed to work with this carriage. Any other STL that moves the CX-1 extruders back is also fine (but come on, download mine :P)

For the Ender 3 V3 Plus:

Normal version (above) and newer quick swap version of my braket (below):

For the Ender 3 V3:

Some slicer suggestions:
-I printed this carriage with eSun ASA+ with 0,2 Layers height and 15% infill. You can use PETG and ABS as well. I don not recommend you to use PLA cause it's a bit fragile and can not withstand the high temperatures.

Hope you like this stl :D