S-91255A566 1/4"-28 x 1 1/4" ASTM F835 Steel Button Head Hex-Drive Screws
Steel 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
- Superior corrosion resistance with black-oxide finish for extended service life in demanding industrial environments
- Precise Class 3A thread fit ensures reliable fastening with minimal vibration loosening in critical applications
- High tensile strength (120,000 psi) provides exceptional load-bearing capacity for structural assemblies
- Rockwell C39 hardness rating maintains thread integrity and prevents stripping during repeated installations
- Low-profile button head design offers flush mounting while maintaining substantial bearing surface
- 5/32" hex drive compatibility enables secure tool engagement and controlled torque application
- Full threading along 1-1/4" length allows for adjustable positioning and maximum grip range
Professional Applications & Engineering Value
Engineered for precision assemblies requiring both high-strength fastening and low-profile clearance, these black-oxide alloy steel button head screws solve critical challenges in machinery, automotive, and aerospace applications. The UNF fine threading (1/4"-28) provides superior resistance to vibrational loosening compared to coarse threads, while the Class 3A thread fit ensures consistent clamping force in precision-machined components. The black-oxide surface treatment creates a protective barrier against corrosion without adding significant thickness, maintaining dimensional accuracy in tight-tolerance assemblies. These fully threaded screws distribute clamping force evenly across the entire engagement length, preventing stress concentration in sensitive electronic enclosures or precision instruments.
Specification Summary & Compliance
Manufactured to exacting ASME B18.3 and ASTM F835 specifications with Class 3A thread fit precision. Compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) environmental regulations. Features UNF fine threading with right-hand orientation and meets dimensional requirements for rounded head screw applications in industrial and commercial settings.
