Titan 520-031 Head Screw

Head Screw for Graco Airless Spray Guns

The Graco 520-031 Head Screw is a threaded fastener that secures the front head or fluid housing assembly to the main body of several Graco airless spray gun models, including the Airless SGX 20, Airless S5, and Airless G-15 XL Gun. Within these spray gun designs, the front head contains critical sealing elements that separate pressurized coating material from the atmosphere and direct flow toward the spray tip. The head screw provides the clamping force necessary to compress gaskets, o-rings, or sealing washers between the front head and gun body, creating a leak-proof barrier capable of withstanding the high operating pressures common to airless spraying, typically ranging from 1500 to 3000 PSI or higher. Without proper clamping force from the head screw, the seal may not fully compress, allowing material to escape past the joint. This can result in external leakage that wastes coating, creates a mess, and poses safety hazards due to slippery surfaces or high-pressure fluid injection risks. Over the service life of the spray gun, head screws can suffer from several failure modes. Repeated removal for cleaning or seal replacement can strip the threads in the gun body or on the screw itself. Corrosion from exposure to water-based paints, solvents, or cleaning solutions can degrade the screw finish and lead to seizure or weakening. Overtightening can stretch the screw threads, reducing clamp load, while undertightening may allow the head to loosen under vibration. Replacing a damaged or missing head screw restores proper clamp force, eliminates leakage at the head joint, and ensures that internal seals function as designed. Using the correct screw specification is critical, as incorrect thread pitch or length can damage the gun body or fail to provide adequate sealing pressure.