Black Oxide Finish is a conversion coating (not an applied coating) because it results from a chemical reaction with the iron present in the metal fastener and forms an integral protective surface.

It is a color of the base metal, which neither removes nor deposits metal; therefore it adds, at the most, 5 to 10 millionths of an inch to the fastener's dimensions. Likewise, it cannot chip, peel or rub off. The item maintains 99% of its conductivity making black oxide a popular finish for electrical parts. The color is a deep black rather than the grayish-black appearance of a black phosphate, and remains consistent at temperatures as high as 900 F degrees.

Black oxide also resists abrasions better than phosphate. One of the most important advantages of black oxide is that there is almost no risk of hydrogen embrittlement because the process does not involve electro-plating nor does it require an acid-activation. Black oxide neither enhances nor detracts from a fastener's resistance to corrosion. The post-treatment oil application offers good indoor corrosion protection, but a zinc-plated part is more resistant to rust. However, parts with a black oxide finish will not suffer from white corrosion.

• Head Style: Socket, Material: Alloy Steel, Finish: Black Oxide, Thread: Coarse Thread (UNC)
• RoHS Compliant, # Threads: 1/4-20, Thread Style: Right Thread, (Inch)
• A hex socket head screw with an enlarged, unthreaded, cylindrical shoulder under the head
• For rotation/sliding applications, pulley shafts, in punch and die work, or as a bearing pin.
• Shoulder screws are also referred to as "stripper bolts".ALLOY STEEL ASME B18.3-1988

Head Style: Socket, Material: Alloy Steel, Finish: Black Oxide, Thread: Coarse Thread (UNC)Import