McMaster-Carr 91251A115 Black-Oxide Alloy Steel Socket Head Screw 4-40 Thread Size 1" Long Partially Threaded

# Socket Head Screw The McMaster-Carr 91251A115 Black-Oxide Alloy Steel Socket Head Screw is designed for applications requiring high strength and durability. This partially threaded screw features a 4-40 thread size and measures 1 inch in length, making it an ideal choice for various mechanical and assembly tasks. ## Key Features • **Material**: Constructed from black-oxide alloy steel, providing enhanced corrosion resistance and strength. • **Thread Size**: Standard 4-40 thread size ensures compatibility with a wide range of fastening applications. • **Length**: Measures 1 inch, ideal for securing components in tight spaces. • **Design**: Socket head design allows for easy installation and removal using an Allen wrench, ensuring a secure fit. • **Finish**: Black oxide finish adds a layer of protection against wear and tear while offering a sleek appearance. ## Applications • **Mechanical Assembly**: Perfect for use in machinery, automotive applications, and electronics where strength and reliability are critical. • **Compatibility**: Suitable for use with a variety of nuts, washers, and sockets, making it versatile for different projects. • **Industrial Environments**: Ideal for environments requiring robust fastening solutions that can withstand wear and corrosion. ## Benefits • **Enhanced Durability**: The black-oxide coating provides superior resistance to rust and oxidation, prolonging the lifespan of the screw. • **Easy Installation**: The socket design facilitates quick and efficient fastening, reducing assembly time and effort. • **Versatile Use**: The compact size and strong material make it a go-to choice for a variety of applications, from DIY projects to industrial uses. --- *Product information compiled with AI assistance for reference purposes.*