Y-Axis Motor Relocation Bracket for large NEMA-17 motors on the Ender 3 v1

Attention: A Variant of This Model Is Now Available With A Belt Tensioner. 

Y-Axis Motor Relocation Bracket for large NEMA-17 motors on the Ender 3 v1

Modeled to accommodate the vertically oriented 2040 extrusion and v-roller movement of a stock, original Ender 3.

[DISCLAIMER] While I successfully printed an earlier revision of this bracket which serves my needs, I've since made untested changes to the model based on that experience. If you choose to use this mod, keep in mind you're alpha-testing these changes. Your feedback would be greatly appreciated.

This part is designed to accomplish the following on an original Ender 3:

• Provide clearance between the Y-Axis stepper motor and bed-adjustment knobs.

• Create a level, parallel belt path from the printer bed.

• Maintain (approximately) the same Y-endstop position

In addition, the design is optimized to:

• Interface snugly with the Ender 3's v-slot extrusions (you might need a hammer)

• Be printable with minimal supports (see slicer recommendations)

• Use Ruthex threaded inserts instead of direct-threading into plastic wherever possible.

Parts Needed:

A note on machine screws: All countersunk machine screws can be subbed out for button head machine screws, but you will need to use longer screws.

Tools and Installation:

In addition to the obvious hex keys, you will need a soldering iron with a conical tip to gently push each insert into place at 240-300°c (into PETG.) Any plastic squeeze-out can be trimmed flush with a razor blade. 

You will need to tap the holes at the end of the 2040 extrusion with an M5 tap before installation.

Start by installing the threaded inserts. The M3 inserts should be set either flush or depressed. The M5 inserts, inserted from the idler-facing side of Bracket B, may benefit from sitting proud to double as a bushing.

Next, install the mounting sleeve. You may find that you need a hammer in order to do this. If you do, use a block to more evenly distribute the force and avoid denting the part. Mine was difficult to mount, but I've since increased tolerances between the sleeve and extrusion. I haven't tested these changes myself, so once more, your feedback would be helpful.

Next, the stepper motor should be mounted to Bracket A via a countersunk M3 x 8 machine screw through the one hole which will accommodate it. 

Mount Bracket A to the Mounting Sleeve. Insert both M5 x 30 screws (axles) through Bracket A, and install both idler pulleys. If using both smooth and toothed idlers, the upper pulley should be toothed, and the lower pulley smooth.

Loosely thread both M5x30 axles into their corresponding threaded inserts in Bracket B; just enough to keep the pulleys from falling off. Mount Bracket B to the Mounting Sleeve.

Install the remaining 3 motor mount screws through their holes in Bracket B, through Bracket A, and into the stepper motor.

The M5 axles should be tightened just enough to eliminate lateral play in the idler pulleys, without imparting drag. If at this point the bolt doesn't seem tight enough to remain in place, consider thread lock glue. Alternately, use longer screws (M5 x 35) with nylon lock nuts.

Mount the Y-endstop. The mounting screws for the Y-endstop will thread directly into the plastic of Bracket B and the Mounting Sleeve. Though printing with polyholes should result in fairly accurate holes, you may find you need to ream the holes with a 2mm or 5/64" drill bit. If you find that the pins on your endstop switch protrude further than the endstop cutout can accommodate, consider trimming them with flush-cutters.

The driven GT2 pulley can be loosely mounted to the motor shaft until the belt is mounted.

As for the belt, I recommend fishing it through the rear (motor-mount side) of the extrusion out to the front. Terminate that front end, and mount it to the bed. From there, the other end can be routed through the motor mount pulleys and pulled taught against the rear mount of the print bed. Trim to length, terminate, and mount.

Printing:

Filament:

This part should be printed with a material that is reasonably tough, flexible and somewhat heat tolerant. I would highly recommend PETG, and discourage the use of PLA. For my build, I used PETG-CF for extra stiffness, and I'm quite happy with the result.

Orientation:

The mounting sleeve should be oriented with the M5 countersinks facing the build plate. The orientation of brackets A & B should place their protruding components away from the build plate. 

Suggested Slicer settings:

(These are not rules; just suggestions. Nomenclature per OrcaSlicer)

Quality:

• Nozzle = 0.6mm (to accommodate carbon-fiber filament)

• Layer height = 0.2mm (A lower setting makes for better v-rail fitment) 

Precision:

• Precise wall = Enabled

• Polyholes = Enabled

• Polyhole twist = Enabled

• Precise Z height = Enabled

Strength:

• Wall loops ≥ 2

• Sparse infill density ≥ 75%

• Top shell layers ≥ 7 (default)

• Bottom shell layers ≥ 5 (default)

Support:

Both mating surfaces for the motor and the Y-endstop will require supports. Use “normal” supports, and make sure your clearances are dialed in to avoid excessive adhesion.

Remember to account for shrinkage if you want an accurate part! I had to scale the print to 100.6% on the X and Y axis in order to achieve accurate dimensions with my given printer and filament. In OrcaSlicer, shrinkage compensation can be saved in any given filament profile. 

Changelog:

• 7/19/24 REV 1.20 Corrected interference between endstop sensor and bracket B. Rearranged bracket-to-sleeve bolt pattern. Increased sleeve-to-extrusion tolerances. Added various fillets and chamfers.  

• 7/8/24 REV 1.16.1 Corrected geometric artifact within Bracket A/B conical mating surfaces. Separated each component into independent files.

• 7/8/24 Added a lock-nut variant of Bracket B as a separate file

• 7/7/24 REV 1.16 added embossed letters “A” and “B” to their respective brackets.

• 7/7/24 REV 1.15 fixes a flaw affecting printability of the underhung wings of the mounting sleeve.