495349 - Miller 1/4-20 x 12.5 Inch Hex Washer Head Screw Grade 5

Technical Specifications and Application

The Miller 495349 is a specialized machine screw engineered for specific fastening applications within Miller power sources and welding equipment. For welding technicians and equipment repair specialists, identifying the correct hardware is essential for a successful repair. This screw is defined by its specific dimensions: a 1/4-inch diameter with a coarse thread count of 20 threads per inch (1/4-20 UNC), and an extended length of 12.50 inches. Finding a bolt of this specific length and grade in a standard hardware inventory is often difficult, making this OEM part a necessary procurement for specific chassis repairs.

Material and Grade: The "GR5" designation indicates that this is a SAE Grade 5 fastener. Grade 5 bolts are manufactured from medium carbon steel and heat-treated to achieve a proof load of 85,000 psi and a minimum tensile strength of 120,000 psi. This makes the Miller 495349 significantly more robust than common hardware, capable of handling the torque requirements and shear loads present in heavy-duty welding machines. The "PLD" specification refers to its plated finish, typically zinc, which provides essential sacrificial corrosion resistance, preventing the bolt from seizing due to rust over time.

Head Design: The Hex Washer Head (HEXWHD) configuration is designed for efficiency and hold. The built-in washer face provides a bearing surface that protects the equipment finish and prevents the screw head from embedding into softer materials. It allows for high-torque tightening using standard socket wrenches or nut drivers. Because the washer is integral, there is no risk of losing it during disassembly or assembly in tight, hard-to-reach areas of the machine.

Installation: When installing this 12.5-inch screw, ensure that the threads are clean and aligned correctly to prevent cross-threading, which can be a risk with long fasteners. Verify the torque specifications for your specific Miller machine model to avoid over-tightening. This part is a direct replacement for the original factory component, ensuring that your repair meets all warranty and safety standards required for industrial welding equipment.