The JK42HS40-1204AF-02 NEMA 17 Stepper Motor is a compact and precise bipolar stepper motor designed for 3D printers, CNC machines, robotics, camera platforms, XY/XYZ positioning systems, and automation projects.
It delivers a holding torque of 4.2 kg·cm with a rated current of 1.2A per phase. With a 1.8° step angle, the motor provides 200 full steps per revolution, making it suitable for applications requiring accurate and repeatable positioning.
The motor also features a D-type 5mm shaft for improved grip with pulleys, gears, couplers, and other mechanical components.
Key Features
-
NEMA 17 frame size
-
Holding torque: 4.2 kg·cm
-
Rated current: 1.2A per phase
- 1.8° step angle
- 200 full steps per revolution
- 4-wire bipolar configuration
- 5mm D-type shaft
- 18mm shaft length
-
Detachable 70cm cable
- High positioning accuracy and repeatability
- Excellent starting, stopping, and reversing response
- Brushless design for long service life
- Suitable for open-loop position control
- Speed controlled by input pulse frequency
- Compatible with a wide range of stepper motor drivers
Precise Position Control
Stepper motors move in precise, repeatable increments, making them ideal for applications requiring accurate position and motion control.
The 1.8° step angle provides:
200 full steps per revolution
When used with a compatible microstepping driver, even finer positioning and smoother movement can be achieved.
The motor provides excellent response to:
- Starting
- Stopping
- Reversing
- Position changes
- Speed adjustments
4.2 kg·cm Holding Torque
The motor provides a holding torque of up to:
4.2 kg·cm
This makes it suitable for compact machines requiring a good balance between size, torque, precision, and power consumption.
D-Type Shaft
The motor features a 5mm D-type output shaft.
The flat section of the shaft provides improved grip when connecting mechanical components such as:
- Timing pulleys
- Gears
- Shaft couplers
- Lead screws
- Belt-drive mechanisms
This design helps reduce unwanted slipping between the shaft and attached components.
Detachable Cable
The motor comes with a 70cm detachable cable, making installation, replacement, and maintenance easier.
The 4-wire connection is suitable for use with standard bipolar stepper motor drivers.
Technical Specifications
| Specification |
Details |
| Model |
JK42HS40-1204AF-02 |
| Motor Type |
NEMA 17 Bipolar Stepper Motor |
| Frame Size |
42 × 42mm |
| Step Angle |
1.8° |
| Steps per Revolution |
200 Full Steps |
| Rated Current |
1.2A / Phase |
| Number of Lead Wires |
4 |
| Holding Torque |
4.2 kg·cm |
| Inductance |
3.2 mH |
| Rotor Inertia |
54 g·cm² |
| Shaft Type |
D-Type |
| Shaft Diameter |
5mm |
| Shaft Length |
18mm |
| Cable Length |
70cm |
| Step Angle Accuracy |
±5% |
| Inductance Tolerance |
±20% |
| Resistance Tolerance |
±10% |
Applications
Ideal for:
- 3D printers
- CNC routers
- CNC milling machines
- Laser engravers
- XY and XYZ plotters
- Camera platforms
- Robotics
- Linear motion systems
- Automated equipment
- Positioning systems
- Lead screw mechanisms
- Belt-driven systems
- Pick-and-place machines
- DIY motion-control projects
Important Notes
-
A compatible bipolar stepper motor driver is required to operate this motor.
-
The driver current limit should be configured according to the motor's 1.2A/phase rating.
- Mechanical resonance may occur at certain speeds or with improper installation.
- Stepper motor torque generally decreases as operating speed increases.
The JK42HS40-1204AF-02 NEMA 17 Stepper Motor is a practical choice for projects requiring compact size, 4.2 kg·cm holding torque, precise positioning, and reliable motion control.
