Ender 3 Pro Dual Y Stepper Motors + Alternative Mounts and Tension Plate

Bill of Materials

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Tension Plate + Belt Holders

4 × M3/M2 hex bolts, 20mm

6 × M3/M2 hex bolts, 4mm

2 × M3 hex bolts, 40mm

8 × M3/M2 heat-set inserts

1 × 2m GT2 10mm Gates belt (includes spare length) *Can use any belt under 10mm lying around

Using M2 inserts may need washers depending on type

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Y Stepper Mount

1 × 16T GT2 pulley (16 teeth, 10mm width, 5mm bore)

1 × 20T GT2 idler (toothless, 10mm width, 5mm bore)

2 × M3 heat-set inserts (for guide roller pulley)

1 x Old V-roller (provides 2 double shear bearings)

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Overview:

This is my remix of the Y-axis belt tensioner and stepper mount system provided by Mitsubishi Makes. The design allows for belt tensioning on either side of the Y-axis and reduces the overall system height, giving you more room to use improved spring or silicone spacers under the bed. The belt holders run in their own channels, with outer bolts used to apply tension.

A small amount of lubricant can help keep things moving smoothly. Be mindful of any heat insert, bolt, or printed material that could interfere with smooth motion.

I used the parts listed above, though some connections can technically be made without heat-set inserts. However, the long-term reliability of that is uncertain.

I used M3 inserts, but due to the system’s low height, you may experience part deformation. Sanding can help, or consider using M2 inserts to reduce this risk.

If you have the tools and experience, I recommend placing a heat insert inside the tension plate’s channel. This puts it in compression under belt tension, making it much more secure. I currently use inserts on the outside—so they’re under tension—but I’ve been running the system for weeks with no issues.

The system is designed to work alongside my modified Y stepper mounts, which are also included. These updated mounts support a wider variety of stepper motors. I reused 32/34mm steppers from old Creality printers. The mounts maintain double-shear support for both the motor and the belt roller. Some shorter steppers may not allow for full shear support, but they can still be used. These motors are widely available and often much cheaper from China. You can use a shorter-shank stepper temporarily while waiting for a replacement.

This system is designed for use with a 10mm GT2 belt, however I did file the belt seating on the Y-plate to get a better belt angle.

Notes:

This system replaces one or both Y stepper mounts. Even a single mount offers a meaningful upgrade. You can always add the second one later. (The BOM above is for one mount—double mount parts if you're building both - keep in mind you may need to keep the belt a bit longer to allow for the second stepper)

Depending on your Y-plate, you may lose Y axis max print size due to it hitting a stepper, I simply cut that part away.

If using a double stepper system, the Y axis plate will need to have a section cut away to allow full movement. If people would like, I can design a mount where this isn't needed, but it mmay not be as strong.

For the double-shear system, I repurposed internal bearings from old V-rollers. Just remove the black POM material to access them.

I used 40mm M3 bolts for the secondary guide roller pulley. Optional shims are included but not strictly necessary. You can also us the belt guide pully without double shear.

One end of my 4040 extrusion had to be tapped. This isn’t required if you’re only upgrading one mount, but keep it in mind if you’re installing both—you’ll also need three additional bolts.

I printed the plate and belt holders in PETG, and the stepper mounts in ABS, using a minimum of 40% cubic infill, the plate was printed in 100%. Part orientation is critical—orient parts so that layers are placed under compression wherever possible for maximum strength.

When setup, it may seem you have more tension on one side, loosen a toothed pulley on a stepper and move bed forwards/backwards a few time and retighten. This will even tension and allow the belt to settle.

If a Stepper seems like it's fighting or working in the wrong direction, you may need change the pins on the stepper cable connector, a quick google will tell you how.

This system has been working great for me. Feel free to remix, share, or improve on it!

Credits:

Thanks to the following for their original designs and inspiration:

Mitsubishi Makes

thisisnotfez

CDeviant

redesign of plate and stepper mounts from the awesome system Mitsubishi Makes designed:

https://www.printables.com/model/1294194-ender-3-awd-y-axis-for-12mm-belts