Ender 3v2/pro - Y - single linear rail (MGN12H)

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June 3
Added STEP file for ender3/pro/v2, with two sizes, shorter one for use with longer than stock replacement belts and longer one to use the stock belt. so you can mod things to your liking. This can definitely be improved and eventually will do so. but in the meantime you can too.

Updates

May 3rd:

• LowProfile Rail stop (targeted for ender3max)

May 2rd: 

• Ender3Max platform

April 23rd:

• Added alignment tool, I recommend to print at least 3

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Thanks to Kris (KStank) for helping test this out.

Will no work on ender3 original as it's a 40x20 extrusion instead of 40x40

You will lose a couple centimeters of Z, but I never print that high, so I personally don't mind at least for now. Only way to not loose Z is to buy a second rail and have a dual rail setup, which are very common and easy to find around.

Reverting to stock setup is really easy

• Print in PETG or better
• four M3x8 to secure the block to the MGN12H block
• four M3x6 (or M3x8) to secure the belt to the main piece
• M3x8 + t-nut (m3 2020) as many as you have rail mounting point (12 on 300mm linear rail) - ender3v2 can technically host a 350mm long rail
• one M3x10 or M3x12 to secure the bumper plate.
• on Ender3v2 I used a 300mm linear rail (the aluminum extrusion is 350mm, so anything length of linear rail in between this dimensions will work) 
• Reuse the screws and nuts, M5 I believe they are, you can always use shorter ones if you have any
• 5 heat inserts (m3, 4mm long, 4.6mm or 5.0mm OD) + 2 more if you want a temporary adxl mount.
  
  I don't know if there is a huge difference between an adxl on the block vs attached to the bed. So the adxl here may or may not be recommended. option is there in case it works out. (haven't had a chance to test yet)

Print List:

•  main_block.stl
• belt_holder_1.stl
• belt_holder_2.stl
• endstop bumper.stl

Alternative main block:
A shorter block will allow more Y, only if you are after minimum loss in Y, you might need to remove the crimp at the end of the belt for these to work

• main_block_2mm_shorter.stl
• main_block_4mm_shorter.stl

Optional: (not needed)

• railStop1.stl
• railStop2.stl

Installation:

• unscrew bed leveling wheel
• remove bed carefully, don't loose springs or silicon spacer
• loosen the belt and detach it from the bed frame. 
• remove bed frame, keep nuts and bolts. and store the rest.
• install linear rails (M3x8 + t-nuts) on the right groove , keep a gap of about 15mm between belt tensioner block and the rail. (make sure it's perfectly aligned with the Y direction)
• Add heat inserts to the adapter plate if you haven't done so yet. ( two on each end, where he belt goes, and one in a corner for the bumper that will hit the Y endstop ), and optionally for the ADXL on either side (or both)
• install plate on MGN12H carriage, and use 4 M3x8 screws to secure it
• secure the belt ends: place the belt in the hole, and route it through the bottom, and secure it with the bed holder piece.
• mount the bumper plate on the back right corner.
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• secure the bed metal frame, reusing original nuts and bolts (or use shorter ones if. you have any)
• reinstall the print bed platform.

Tweak your printer Y max in the config if needed.