Dual Z Ender 3 - simple yet powerful + detailed instructions

My take on dual Z for Ender 3 pro - I have to say that this is by far the best upgrade I have done on my printer.

• I wanted simple solution for installing dual Z. I didn't want to “duplicate” the Z stepper as you can't be sure they are synchronized during the print and I didn't want to do any fw changes with second independent stepper.
• With my design you don't have to relocate the PSU, you don't have to loosen the Z axis rollers and then realign again as this will just snap on and the design doesn't make the printer any wider - it doesn't protrude more then the original X belt tensioner.

If you want to install this dual Z, it is necessary to align your Z stepper properly! I have detailed guide here: Better Z motor mount - adjustable and reinforced od autora radkoko | Stáhněte si zdarma STL model | Printables.com

You will need: 

• 3x 608 ball bearing (for both stabilizers and belt tensioner)
• 6x M4x10 flathead screw with T nuts
• 4x M3x10 round head screw
• 2-4x M3,5x8
• 1x M3,5x16 (or something between 12-18 mm)
• 1x 400mm T8 lead screw
• 1x T8 nut
• 2x GT2 pulley for 8mm shaft (I use 40T_8_R) GT2 Pulley collection od autora radkoko | Stáhněte si zdarma STL model | Printables.com
• GT2 belt - minimum length will be 665 + 2*pulley teeth (so for 40T pulleys I have at least 665+2*40=745 mm closed loop belt). You will compensate the length of the belt with tensioner but the closer the length is to minimum the better. If you can't find the right length in store don't be worried to make one.
• printed parts in the list and the Z axis stabilizer Z axis stabilizer - Ender 3 od autora radkoko | Stáhněte si zdarma STL model | Printables.com

Steps to install:

1. Move your Z axis all the way down or support it in place so it can't drop down.
2. Loosen the Z lead screw from the coupling and swap it for the 400 mm one. Tighten the coupling.
3. Check the lead screw for alignment and if needed, do your Z motor alignment, if you need instructions follow the link above. Don't skip this step as you could run into problems!
4. Move the Z axis up and install stabilizer in proper position: Z axis stabilizer - Ender 3 od autora radkoko | Stáhněte si zdarma STL model | Printables.com
5. On the right side install the dual Z MAIN file - first take out the screw between the rollers, slide the top part of the print on the roller spacer and then snap the lower one on the bottom roller spacer. Should be decent tight fit. Reinstall the middle screw.
6. Press bearing in the right lead screw stabilizer and install the stabilizer. The right stabilizer is designed to support the lead screw being properly aligned so you don't need to make any adjustments.
7. Put GT2 pulley on both lead screws ends - on the left stabiliser so that the pulley is supported by the stabiliser bearing - this will also help to support the Z axis and should reduce Z axis banding. Number of teeth is purely up to you, just use puleys of the same size on both lead screws :). Also if you have top mounted spool holder, move it so it doesn't later colide with belt.
8. Insert the right lead screw through the bearing and through the lead screw nut.
9. Put the GT2 belt on the pulleys. If your belt is already well tensioned then you can skip steps 10 and 11.
10. Assemble the belt tensioner - press the idler pulley on the 608 bearing and press the bearing on the shaft of the tensioner body. Install long M3,5 screw into the hole in shaft for bigger strength of the part, if the bearing came too easy on the shaft, install the screw with big washer to secure the bearing in place or use some glue.
11. Loosely install the belt tensioner on the right side and slide it across the beam until the belt isn't tight just enough - no need to really tight one. Tighten the tensioner screws. (According to the length of your belt you can install the pulley outside the belt loop, inside the belt loop or even use more than one belt tensioner and make this kind of zig zag pattern).

Steps to align both sides of your Z axis:

For much easier process print the alignment blocks otherwise if you don't want to you can substitute them with manually measuring the distance.:

Dual Z axis alignment block od autora radkoko | Stáhněte si zdarma STL model | Printables.com

1. Put alignment blocks in place and move the Z axis down so it touches one of them (without blocks measure the distance on both sides and compare).
2. Loosen the lead screw pulley on right side of printer, hold the lead screw so it won't drop down from the pulley. For easier workflow you can temporarily fix the lead screw to the T8 nut with some sticky tape or just anything.
3. Now set both sides to sit on the alignment block (right side will move easily, left side will need you to rotate the lead screw).
4. Tighten the pulley on right lead screw and make sure it sits on the bearing.
5. Move the Z axis carefully up and down and check if everything sits fine, move it way up and back down and test the alignment blocks fit again, if you did everything well, it should be still fine.
6. Calibrate your bed level.
7. Enjoy the printing more then before.

I hope you find this useful but it is tested by me and I am very happy with the result. If you have any ideas or tip I'd be glad if you leave a comment. Thank you.

If you really like the design and/or just want to appreciate my work and time spend, you can buy me a coffee.