S-91355A185 1/4"-28 x 1/2" Steel Flanged Button Head Hex-Drive Screws
Steel Flanged Button Head Hex-Drive Screws
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Basic Information
Head Parameters
Dimensions
Thread Parameters
Tip & Drive Parameters
Material & Strength
Temperature & Environment
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Key Features & Benefits at a Glance
- Exceptional tensile strength of 120,000 psi for reliable performance in demanding applications
- Superior corrosion resistance from Black-Oxide Alloy Steel, extending service life in harsh environments
- Precise Class 3A thread fit ensures tight, secure connections with minimal vibration loosening
- Flanged design with wide rounded head provides increased bearing surface for better load distribution
- Fine UNF thread spacing delivers enhanced grip and holding power in precision assemblies
- Hex drive compatibility with 5/32" drive size enables efficient installation with standard tools
- Full threading along 1/2" length offers maximum engagement depth for versatile fastening applications
Professional Applications & Engineering Value
This Black-Oxide Alloy Steel Rounded Head Screw with 1/4"-28 UNF Class 3A threading addresses critical industrial fastening challenges where vibration resistance and precision alignment are paramount. The fine thread spacing combined with Rockwell C32 hardness ensures superior holding power in machinery, automotive, and aerospace applications where thermal cycling and dynamic loads are common. The flanged hex drive design eliminates the need for separate washers while providing excellent torque transmission during installation. The black-oxide surface treatment creates a durable barrier against oxidation and chemical exposure, making these industrial screws ideal for outdoor equipment, manufacturing fixtures, and heavy-duty assemblies requiring long-term reliability under stressful operating conditions.
Specification Summary & Compliance
This precision fastener features Class 3A thread fit per UNF standards with 1/4"-28 fine threading and right-hand direction. Manufacturing specifications include Rockwell C32 hardness and 120,000 psi tensile strength. The screw is fully threaded with a 1/2" length and 0.563" flange diameter. Compliance includes RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) environmental standards, ensuring safe use across regulated industries.
