S-90519A889 1 1/4"-12 ASTM A108 Hex Nuts

Key Features & Benefits at a Glance

• Left-hand thread design provides secure fastening in reverse-thread applications where standard nuts would loosen under counter-clockwise rotation
• Black-oxide steel construction offers excellent corrosion resistance and durable protection in demanding industrial environments
• Thin profile design (23/32" height) enables installation in space-constrained applications without compromising strength
• Class 2B thread fit ensures precise engagement with mating components for reliable, vibration-resistant connections
• Grade 2 strength rating delivers optimal performance for general industrial applications requiring dependable mechanical properties
• External hex drive style allows for easy installation and removal using standard wrenching tools
• Full regulatory compliance with RoHS 3 and REACH standards ensures environmental responsibility and global market acceptance

Professional Applications & Engineering Value

This left-hand thread hex nut addresses critical engineering challenges in applications where reverse threading is essential for safety and functionality. The 1 1/4"-12 UNF fine threading provides superior resistance to vibration loosening in machinery, rotating equipment, and specialized industrial systems. The black-oxide steel surface treatment creates a protective barrier against corrosion while maintaining dimensional stability. The thin hex nut profile is particularly valuable in compact assemblies and retrofit applications where standard-height nuts would interfere with adjacent components. Engineered to ASTM A108 specifications, this fastener delivers consistent performance in automotive, manufacturing, and maintenance operations requiring reliable reverse-thread fastening solutions.

Specification Summary & Compliance

This precision fastener features Class 2B thread fit tolerance for optimal mating with corresponding threaded components. Manufactured to ASTM A108 material specifications with UNF fine thread form (12 threads per inch) in left-hand orientation. Dimensions include 1 7/8" width across flats and 23/32" height. Fully compliant with RoHS 3 (2015/863/EU) with exemption 6(a) for lead as an alloying element in steel, and REACH (EC 1907/2006) regulations current as of January 17, 2023, covering 233 Substances of Very High Concern.