SG90 Servo Screw Size: The Ultimate Guide to Perfect Mounting and Assembly

Why SG90 Servo Screw Size Matters in Your Projects

The SG90 servo is a staple in robotics, RC vehicles, and DIY electronics due to its compact size, affordability, and versatility. However, even seasoned hobbyists often overlook a critical detail: the screw size. Using the wrong screws can lead to stripped threads, unstable mounts, or even damaged servos. This guide dives deep into the SG90’s screw specifications, helping you avoid common pitfalls and achieve professional-grade results.

Understanding the SG90 Servo’s Design

The SG90 is a 9-gram micro servo with a plastic or metal gearset, designed for lightweight applications like drone flaps, small robotic arms, or camera gimbals. Its housing includes pre-drilled holes for mounting the servo itself and attaching accessories like horns or arms. These holes are precision-engineered to specific screw sizes, ensuring a snug fit without compromising structural integrity.

SG90 Screw Size Specifications

The SG90 servo uses two primary screw types:

Mounting Screws: These secure the servo to a frame or bracket. Horn/Arm Screws: These attach control horns or arms to the servo’s output shaft.

Mounting Screw Size:

Diameter: M2 (2mm) Length: 6–8mm (varies by application) Thread Type: Standard metric coarse thread (M2x0.4)

Horn Screw Size:

Diameter: M1.4 (1.4mm) Length: 4–5mm Thread Type: Fine thread (M1.4x0.3)

These dimensions are critical. Using larger screws can crack the servo’s plastic casing, while shorter screws may fail to grip properly.

Material and Strength Considerations

SG90 screws are typically made of steel or nylon. Steel screws offer durability but add minimal weight, while nylon variants are lightweight and corrosion-resistant—ideal for drones or outdoor projects. However, nylon screws may strip more easily if over-tightened.

Tools You’ll Need

Precision Screwdrivers: A PH0 or PH00 Phillips head for M2 screws, and a flathead or hex key for horn screws. Thread-Locking Fluid: To prevent vibrations from loosening screws (optional but recommended). Calipers: For measuring screw lengths if replacements are needed.

Common Mistakes to Avoid

Over-Tightening: This strips threads or cracks the servo housing. Tighten just enough to eliminate wobble. Mixing Screw Types: Using horn screws for mounting (or vice versa) leads to poor grip. Ignoring Thread Pitch: M2x0.4 and M1.4x0.3 threads are not interchangeable with similar-sized screws from other standards (e.g., imperial).

Where to Find Replacement Screws

SG90 servos usually come with a small packet of screws, but replacements are easily sourced:

Online Retailers: Amazon, eBay, or specialty sites like ServoCity. Hardware Stores: Metric screw assortments often include M2 and M1.4 sizes. 3D Printing: Custom screws can be printed in nylon for unique projects.

By understanding these basics, you’ll ensure your servo stays securely mounted, performs reliably, and survives the rigors of motion.

Advanced Tips for SG90 Servo Installation and Maintenance

Now that you know the screw specs, let’s explore advanced techniques for mounting SG90 servos in complex projects, troubleshooting common issues, and extending the lifespan of your hardware.

Practical Applications and Mounting Solutions

Robotic Arms: Use M2 screws to attach the servo to 3D-printed brackets. Add rubber washers to dampen vibrations. For multi-servo setups, ensure screws don’t protrude into adjacent components.

RC Cars and Boats: In high-vibration environments, combine steel screws with thread-locking fluid. For waterproofing, coat screws with silicone grease.

Drones and UAVs: Replace metal screws with nylon ones to save weight. Ensure horn screws are tight to prevent control surfaces from detaching mid-flight.

Overcoming Installation Challenges

Stripped Screw Holes: If the servo’s threads wear out, insert a helicoil or fill the hole with epoxy and re-drill. Misaligned Mounts: Use shims or adjustable brackets to correct alignment before tightening screws. Limited Space: Opt for low-profile screws or file down the ends to avoid interference with gears.

Comparing SG90 Screws to Other Servos

The SG90’s M2/M1.4 screws differ from larger servos like the MG996R (M3 screws) or the TowerPro SG5010 (M2.5). Always verify screw sizes when swapping servos in a project.

Step-by-Step Installation Guide

Prepare the Surface: Clean mounting areas to remove debris. Insert Screws: Hand-tighten first to avoid cross-threading. Final Tightening: Use a screwdriver to apply gentle pressure—stop when resistance increases. Test Movement: Manually rotate the servo to check for obstructions.

Maintenance Tips

Regular Inspections: Check screws for looseness every 10–15 operating hours. Lubrication: Apply a drop of silicone oil to screw threads to prevent rust (for metal screws). Storage: Keep spare screws in labeled containers to avoid mix-ups.

Conclusion: Precision Equals Performance

The SG90’s tiny screws might seem insignificant, but they’re the backbone of any project’s reliability. By choosing the right size, material, and installation technique, you’ll unlock the full potential of this mighty micro servo. Whether you’re building a robot, tweaking an RC car, or experimenting with automation, mastering SG90 screw sizes ensures your creations move smoothly and last longer.

This guide equips you with the knowledge to tackle SG90 projects confidently. Remember: in the world of micro servos, every millimeter matters!