Can You MIG Weld Spider Gears?

Yes, it is possible to MIG weld spider gears, but it requires a high level of expertise and precision. Spider gears are typically made of hardened steel, which can be challenging to weld due to its high strength and hardness. To successfully MIG weld spider gears, you’ll need to consider several technical factors and follow a specific welding process.

Understanding Spider Gears and Their Welding Challenges

Spider gears, also known as differential gears, are an essential component in the differential assembly of many vehicles, including cars, trucks, and off-road vehicles. These gears are responsible for distributing power to the wheels, allowing them to rotate at different speeds when the vehicle turns.

The hardened steel construction of spider gears makes them highly durable, but it also presents a significant challenge when it comes to welding. Hardened steel is known for its resistance to deformation and its high tensile strength, which can make it difficult to achieve a strong, reliable weld.

Selecting the Appropriate MIG Welding Equipment

can you mig weld spider gearsImage source: Mig weld example

To MIG weld spider gears, you’ll need to use a wire feed welder with a high-temperature setting, typically around 115 amps or higher. This high-amperage setting is necessary to generate enough heat to effectively weld the hardened steel.

The recommended welding rod for this task is a 7018 rod, which has a higher tensile strength than other rods, making it more suitable for welding hardened steel. The 7018 rod is designed to produce a strong, ductile weld that can withstand the stresses and loads placed on spider gears.

Preparing the Spider Gears for Welding

Before you begin welding, it’s crucial to ensure that the spider gears are properly cleaned and prepared. Any dirt, grease, or other contaminants on the surface of the gears can interfere with the welding process and compromise the integrity of the weld.

Start by thoroughly cleaning the gears using a degreaser or solvent, and then use a wire brush or abrasive pad to remove any rust or scale. It’s important to ensure that the welding surfaces are clean and free of any impurities.

Aligning and Welding the Spider Gears

Proper alignment of the spider gears is essential for the success of the welding process. The gears must be positioned precisely to ensure that the welding is done in a way that minimizes stress on the gears.

To achieve this, you can weld only a few teeth on each side of the spider gears, allowing the wheels to spin about half a turn independently before they lock. This technique helps to distribute the stress evenly across the gears and reduces the risk of gear failure or axle breakage.

When welding the spider gears, it’s important to use a steady, controlled hand and to maintain a consistent welding speed. Rushing the process or applying too much heat can lead to warping, cracking, or other defects in the weld.

Considerations for DIY Users

It’s important to note that welding spider gears is not a recommended practice for most DIY users. The process requires a high level of skill and precision, and even small mistakes can lead to significant problems, such as gear failure or axle breakage.

If you do choose to weld spider gears, it’s crucial to have a thorough understanding of the welding process, the equipment required, and the potential risks involved. It’s also recommended to seek guidance from experienced welders or professionals before attempting this task.


While it is possible to MIG weld spider gears, it is a highly technical and challenging process that requires a significant level of expertise and precision. By understanding the unique characteristics of spider gears, selecting the appropriate welding equipment, and following a careful welding process, it is possible to achieve a strong, reliable weld. However, for most DIY users, it is generally not recommended to attempt this task due to the high risk of failure and the potential for serious consequences.