Tower Pro MG958 18KG Digital Metal Gear Servo (180°)

Specifications

• Model: Tower Pro MG958

• Stall Torque: 18.0 kg-cm (at 4.8V) to 20.0 kg-cm (at 6.6V)

• Operating Speed: 0.18 sec/60° (at 4.8V) to 0.15 sec/60° (at 6.6V)

• Operating Voltage: 4.8V - 6.6V DC

• Rotation Range: 180 Degrees

• Gear Type: All Metal Gears

• Motor Type: Brushed DC

• Spline: 25T (H25T)

• Dimensions: 40mm x 20mm x 37.4mm

• Weight: 65g

• Dead Band Width: 1 µs

Key Applications and Projects

• 1/8 and 1/10 Scale RC Vehicles: Providing the immense steering torque required to turn large, heavy off-road tires in mud, dirt, and rock-crawling environments.

• Custom Robotic Arms: Acting as the primary shoulder or elbow lifting joints in DIY robotic manipulators that require heavy payload capacities.

• Animatronics & Automation: Driving heavy latches, trapdoors, or large camera pan-tilt mechanisms that standard servos cannot budge.

Unlock New Capabilities (Project Evolution) The Heavy-Duty Robotic Gripper: Standard micro servos struggle to grip heavy objects securely without stalling. By integrating the MG958 into a 3D-printed or aluminum robotic claw assembly, you can utilize its massive 18KG holding torque to firmly grasp, lift, and manipulate substantial items—like full water bottles or heavy tools—without the gears stripping or the motor burning out!

PACKAGE INCLUDED

• 1 x Tower Pro MG958 Digital Servo

• 1 x Large Round Plastic Servo Horn

• 1 x Single-Arm Plastic Servo Horn

• 1 x Double-Arm Plastic Servo Horn

• 4 x Rubber Vibration-Damping Grommets

• 4 x Brass Mounting Eyelets

• 5 x Phillips Head Mounting Screws

FREQUENTLY ASKED QUESTIONS (FAQ)

1. What is the maximum torque of the MG958 servo? This servo is rated for up to 18KG of torque.

2. Are the gears inside plastic or metal? The MG958 features a heavy-duty, all-metal internal gear train.

3. What is the purpose of the ribbed metal section on the body? That is an integrated aluminum heatsink. It helps dissipate the heat generated by the motor during high-torque operations, preventing the servo from burning out.

4. What type of spline does the output shaft use? It utilizes an industry-standard H25T (25 Tooth) spline.

5. What is the wiring color code?

• Yellow: Signal

• Red: Positive Power

• Brown: Negative Ground

6. What are the physical dimensions of the servo body? The main body measures 40mm x 20mm x 37.4mm. The total width including the mounting tabs is 54.2mm.

7. Does it come with mounting hardware? Yes, the package includes rubber grommets, brass eyelets, and mounting screws.

8. What are the rubber grommets and brass eyelets for? They are used for vibration isolation. You insert the brass eyelet into the rubber grommet, and place that assembly into the servo's mounting tabs. This protects the servo from high-frequency vibrations in gas-powered RC vehicles.

9. Can I power this directly from an Arduino's 5V pin? No. A high-torque servo like this will draw significantly more current (amperage) than a microcontroller can provide, which will cause your Arduino to crash or burn out. You must use a dedicated external power supply or UBEC.

10. Is this a digital or analog servo? The MG958 is a digital servo ("DIGI"), which provides faster response times and better holding power compared to traditional analog servos.

11. Is the servo waterproof? No, the standard MG958 is not waterproof. There are visible seams where the casing meets.

12. What size screw goes into the top of the spline? The center of the spline features an M3 x 0.5mm thread with a 7mm depth for securing servo horns.

13. What is the distance between the mounting holes? The distance between the mounting holes on the same tab is 10mm, and the distance across the body from hole-center to hole-center is 47.5mm.

14. Are aftermarket aluminum horns compatible with this? Yes, any aftermarket horn specifically designed for a 25T spline will fit perfectly.

15. What type of motor is used inside? It utilizes a high-power brushed DC motor.

16. What is the transit speed of this servo? It operates at 0.18 sec/60° at 4.8V, and speeds up to 0.15 sec/60° at 6.6V.

17. Can I rotate this servo a full 360 degrees? No, this is a standard positional servo with a physical rotational limit (typically around 120 to 180 degrees depending on the range of your PWM signal). It is not a continuous rotation motor.

18. What is the weight of the MG958? The servo weighs approximately 65 grams.

19. How do I control it with an Arduino? You can use the standard Arduino <Servo.h> library by connecting the Yellow signal wire to a PWM-capable digital pin. Ensure the servo's Red and Brown wires are powered by an external 5V-6V battery or UBEC, and tie the external ground to the Arduino's ground.

20. What is the dead band width? The dead band width for the MG958 is 1 microsecond (1 µs), providing excellent centering precision and highly responsive control.