S-95955A229 4-40 x 1/2" Left-Hand-Thread Stainless Steel Button Head Hex-Drive Screws
Left-Hand-Thread Stainless 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
- Corrosion-resistant 18-8 stainless steel ensures long-lasting performance in harsh environments, reducing maintenance costs
- Left-hand thread direction provides secure fastening in applications where standard right-hand threads may loosen due to rotational forces
- High tensile strength of 80,000 psi delivers reliable load-bearing capacity for demanding mechanical assemblies
- Class 2A thread fit with UNC coarse threading enables quick installation and superior vibration resistance
- Rockwell B85 hardness maintains thread integrity and prevents stripping during repeated use
- Fully threaded design offers maximum grip length and consistent holding power across the entire fastener
- RoHS 3 and REACH compliance guarantees environmental safety and regulatory acceptance for global industrial applications
Professional Applications & Engineering Value
These 4-40 UNC left-hand thread rounded head screws solve critical reverse-rotation challenges in machinery, automotive, and precision equipment. The 18-8 stainless steel construction provides inherent corrosion resistance, eliminating failures in humid or chemical-exposed environments. With a coarse UNC thread and Class 2A fit, installation is accelerated while maintaining vibration resistance—ideal for high-stress assemblies. The fully threaded button head design distributes clamping force evenly, preventing joint loosening in dynamic applications. Engineers specify these left-hand threaded fasteners for counter-rotational systems, safety mechanisms, and maintenance-sensitive installations where reliability is non-negotiable.
Specification Summary & Compliance
This fastener meets UNC thread standards with Class 2A tolerance for consistent fit. Dimensions include #4-40 thread size, 1/2" length, and 1/16" hex drive. Material properties include Rockwell B85 hardness and 80,000 psi tensile strength. Compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations, ensuring environmental safety.
