Overview
The MGN12 Linear Rails X-Axis Kit is designed for the original Creality Ender 3 and Ender 3 Pro 3D Printers. It is Intended to replace the stock v-wheel rollers, offering high precision and smooth motion.
- High Positional Accuracy
- CNC Machined Aluminum Brackets
- Steel core GT2 6mm Belt
- Lightweight Modular Y Carriage
Package Contents

Required Tools

Hex Wrenches
The installation will require the 2.0, 2.5 and 3mm hex wrenches, found in the Ender 3 toolset.

Open Wrench
The installation will require the 8mm open wrench, found in the Ender 3 toolset.

Medium Threadlocker
While optional, we recommend the use of a medium strength thread locking compound, used to secure threads on all metal-to-metal connections.
1. Remove Belt
Loosen the belt tensioner on the right side of the X axis until the belt goes slack. This is fastened by (2) M4 x 8mm screws as pictured.
Once slack, disconnect the belt ends from the X carriage by sliding them out of the rear notches.

2. Remove Fan Shroud
Remove the fan shroud by loosening the (2) M3 x 6mm screws on the top and left side.

3. Remove Hotend
Remove the hotend by loosening the (2) M3 x 16mm screws.

4. Remove Carriage
Remove the carriage from the X axis by loosening the (3) M4 x 40mm screws.
Place the 8mm open wrench on the eccentric nut to brace it while removing the lower screw.

5. Mount Linear Rail
To prepare the backplate (B) for installation, mount the 300mm MGN12 Linear Rail (C) using the included (6) M3 x 6mm sockethead screws.
Mount the adapter bracket (A) to the MGN12H block using the included (4) M3 x 6mm sockethead screws.

6. Prepare Backplate
Insert the (4) M5 screws from Package B through the lower rear backplate.
Loosely thread the (4) M5 T-nuts from Package B on from the front.

7. Install Backplate
Turn the (4) T-nuts so that they are horizontal, then slot them into the rear v-slot extrusion channel of the X axis.
Tighten the M5 screws from the back using the 3mm hex wrench.

8. Install Carriage
Attach the carriage to the MGN12H adapter block using the included (2) M5 x 8mm screws from Package A.

9. Install Hotend
Mount the hotend on the carriage using the original (2) M3 x 16mm screws from step 3.

10. Install Fan Shroud
Reattach the fan shroud using the original (2x) M3 x 6mm screws from step 2.

11. Install Belt
Reattach the belt ends to the X carriage by sliding them into the rear notches.
Tension the belt as needed before tightening down the M4 screws.
