Robotic Actuator EBA-17-M

---

The EBA-17-M (3mm) is a high-torque planetary gear actuator for NEMA17 motors, using a 3mm ball bearing. At a 120:1 ratio — over 3× the ratio of the standard EBA-17 — for builds where torque matters more than speed.

Efficiency                            Output Torque*

 70% (conservative)            42.0 Nm

 80% (typical)                       48.0 Nm 

 85% (optimistic)                 51.0 Nm

Typically 70–85% for 3D-printed planetary gears due to friction — real-world loss, not just a formality.

Efficiency                            Force at 200mm**

 70%                                       210.0 N

 80%                                       240.0 N

 85%                                       255.0 N

That's roughly 21–26 kg-force at 200mm, with ~240.0 N as the middle estimate— for reference, that's roughly the weight of a 5-gallon water jug pulling on a lever arm 20cm from the joint.

A couple of caveats worth keeping in mind: this is the actuator's torque capability, not necessarily what the arm can safely sustain — your printed gears, shaft, and mounting hardware may fail before the motor's rated torque is reached, especially with PLA/PETG gears under repeated load. 

* Calculator based on a standard common model NEMA17 stepper motor of 0.5 Nm.

** Torque to force at your 200mm (0.2m) lever arm.

• Soldering Iron
• Hex key M3 
• Hex key M4 

• 3D filament 1.75, 1KG, ±0.02 mm, PLA+ or ABS or PA-CF  

• Ball Bearings 3mm   60 PCS
  *You can use 3mm plastic balls from airsoft or Chrome steel for the ball bearing. 
• Synthetic Grease PERMATEX 

Screws, nuts & washers 

• M3 Screws M3x8mm    8 PCS
• M4 Screws M4x8mm    4PCS
• M4 Screws M4x12mm    4PCS
• M4 Nuts    8 PCS  

Inserts

• M3 Inserts M3x6mm    8 PCS 

Bearings

• 625 16x5x5mm     4 PCS

• Nema 17 Stepper Motor  1 PCS