Elevate your coating projects with the Graco Cap Nut designed for peak performance and reliability. Featuring precision engineering, this replacement part optimizes your Graco 116424 assembly—ensuring secure seals and consistent fluid flow in demanding airless sprayer operations. Built for compatibility with a wide range of fluids, it withstands wear and tear to maintain proper connections in professional coatings applications. Its robust design also supports high-pressure filtration systems to keep contaminants at bay. Ideal for professional surface preparation equipment, it delivers unmatched reliability under continuous use.
Maintaining your equipment is simpler than ever thanks to this Cap Nut’s corrosion-resistant finish and universal sizing. Effortlessly replace worn parts and prevent downtime, trusting in the longevity and performance for seamless spray cycles and optimal surface preparation results. Experience smoother finish quality and prolonged pump life with each replacement.
$6.3The Graco 116424 Cap Nut is a precision-engineered accessory integral to advanced fluid handling and coating delivery systems produced by Graco since 1947. Designed to provide a robust seal at critical junctures of spray gun assemblies and pump components, the cap nut optimizes connection integrity under dynamic pressures. Manufactured to interface seamlessly with piston rods, packings, and fluid housing ports, this component enhances overall pump efficiency and mitigates wear within high-demand environments. In airless finishing systems where consistent performance is non-negotiable, the cap nut’s geometry ensures minimal leakage while maintaining thread engagement and resisting torsional fatigue inherent in an airless sprayer configuration.
By optimizing thread pitch at a fine 32 TPI (threads per inch) and employing a chamfered nose profile, the Graco 116424 Cap Nut ensures precise axial alignment during assembly. The part is machined with ±0.005 inch tolerance on external diameter and features a knurled flange for ergonomic hand-tightening where tool-free service is essential. A PTFE sealing washer seat within the internal cavity provides enhanced chemical resistance against solvent-based coatings and abrasive slurries. Ideal for compatibility with PTFE, UHMWPE, and nitrile O-rings, the cap nut resists stress cracking in high-temperature cycles while maintaining uniform compressive load distribution for professional coatings setups.
The cap nut is crafted from 17-4 PH stainless steel, offering a tensile strength exceeding 180 ksi after heat treatment and boasting a Rockwell C hardness of 28–32. This metallurgy selection balances corrosion resistance and fatigue performance, crucial for fluid circuits exposed to abrasive particulates or chemical agents. Surface treatments include passivation per ASTM A967 standards, ensuring consistent oxide layer formation. Finite element analysis confirms that at 5,000 psi operational pressures the component maintains a safety factor above 1.5, even under cyclical loading. Additionally, the precise internal bore geometry supports effective high-pressure filtration mesh integration ahead of critical pump inlet interfaces.
Installation guidelines recommend a tightening torque of 11–13 lb-ft to achieve optimal seal compression without yielding the fine threads. Engineers must account for thermal expansion differentials between the stainless steel cap nut and aluminum pump bodies, typically applying a thin PTFE lubricant to reduce dynamic friction coefficients to below 0.12 μ. The cap nut’s flank angle of 60° ensures reliable load transfer into radial sealing surfaces, contributing to extended seal longevity by distributing pressure evenly. Quality control processes include 100% thread gauge inspection and non-destructive dye penetrant testing to detect any micro-cracks or surface anomalies prior to assembly.
Within high-volume painting and protective coating operations, the Graco 116424 Cap Nut is deployed in airless pump assemblies and manifold blocks to secure fluid pathways against backflow or pressure spikes. Its compatibility with both solvent-based and waterborne chemistries makes it indispensable in automotive refinish lines and industrial maintenance facilities. The part’s compact dimensions—0.4 inch external diameter and 0.35 inch height—allow direct integration into spray headers, reducing dead volume and ensuring rapid color changeover. In combination with upstream high-pressure filtration modules, the cap nut assembly supports micron-level particle retention, optimizing finish quality on metallic substrates. System fatigue tests verify over 10,000 service cycles without detectable wear, enhancing operational reliability.
Comprehensive bench testing measures axial load tolerance up to 2,000 lbf without thread deformation, with leak-rate thresholds below 0.01 cc/min at 5,500 psi. Cycle fatigue analysis using servo-hydraulic rigs simulates operational profiles, revealing less than 0.2% reduction in preload retention after 50,000 cycles. Surface roughness of RMS 16 microinches on sealing faces ensures uniform contact pressure, while destructive burst testing confirms failure modes occur well beyond 6,000 psi. Dimensional audits are conducted with coordinate measuring machines (CMM) to guarantee compliance with ISO 2768-mK tolerances. Such rigorous validation protocols underscore the component’s reliability in demanding industrial fluid systems.
For optimal lifecycle performance, technicians should inspect cap nut threads and sealing surfaces during scheduled maintenance intervals, replacing any unit exhibiting visible galling or corrosion. Cleaning with non-acidic solvents removes particulate build-up within the internal bore, while light re-lubrication with silicone-based grease prevents thread galling. When reinstalling, torque tools calibrated to ±5% accuracy ensure consistent clamp loads. Stored in a dry, temperature-controlled environment, the cap nuts maintain material properties and sealing integrity. By adhering to manufacturer-recommended service procedures, end users can achieve extended component service life and reduced unscheduled downtime in fluid delivery operations.
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