An linear rail upgrade for the ender 3 that was designed to require as little aditional hardware as possible. There's no drilling, cutting or modifyning of the stock parts and all of the metal plates and brackets are still used. As well as the stock belt.

Video guide: https://youtu.be/9o34FILD9Ng

You need:

MGN12H linear rail 300mm. (Might work with some other ones not sure)

4 m5 lock nuts

4 m3 lock nuts

4 m5x12

4 m3x12

8 m3x8 (4 for the sliding block and 4+ for the rail attachment)

4+ m3 t nuts to attach the rail

NOTE

This upgrade can only be performed on the early ender 3 models with the offset holes in the y axes gantry plate. (The weels are further back on one side than the other.)

Happy making!