S-99891A105 1/4"-28 Hex Nuts

Key Features & Benefits at a Glance

• Exceptional strength and reliability with Grade 8 classification, ensuring high load-bearing capacity and resistance to vibration loosening in demanding applications.
• Superior corrosion protection provided by zinc yellow-chromate plating, extending service life in harsh industrial environments and reducing maintenance needs.
• Secure reverse-threading performance with left-hand threads, preventing unintended loosening in rotating machinery and specialized equipment where standard threads may fail.
• Precision fine thread engagement with 1/4"-28 UNF and Class 2B fit, offering tighter tolerances and improved fatigue resistance compared to coarse threads.
• Easy installation and removal using standard 7/16" external hex drive, compatible with common wrenches for efficient assembly and disassembly.
• Durable steel construction ensures long-term integrity under high-stress conditions, maintaining thread form and clamping force over repeated use.
• Wide industrial compatibility with UNF thread standards, making it suitable for automotive, machinery, and equipment requiring fine-threaded left-hand fasteners.

Professional Applications & Engineering Value

This Grade 8 left hand thread hex nut addresses critical engineering challenges in applications where reverse rotation is present or safety is paramount. The zinc yellow-chromate plated steel construction combats corrosion in industrial settings, reducing failure risks from environmental exposure. Its 1/4"-28 UNF fine thread design provides enhanced vibration resistance and superior clamping force distribution, crucial for high-stress assemblies in automotive, aerospace, and heavy machinery. The left-hand thread direction ensures secure fastening on rotating shafts, mixer blades, and other components where standard right-hand threads could loosen, preventing costly downtime and enhancing operational safety. With a Class 2B thread fit, it guarantees consistent engagement and reliable performance in precision assemblies.

Specification Summary & Compliance

This hex nut conforms to UNF thread standards with a Class 2B thread fit for precise engagement and consistent performance. Dimensions include a 1/4"-28 thread size with fine spacing, 7/16" width across flats, and 7/32" height. Manufactured from high-strength steel and finished with zinc yellow-chromate plating for corrosion resistance, it meets industry requirements for Grade 8 strength classification. The product complies with relevant industrial standards for material composition and plating, ensuring reliability in various engineering applications.