Captive Screws Captive Bolts Fasteners Cap Bolt Black Galvanizing

Captive screws are an engineered class of fastener designed for a permanent hold (captivation) within a target assembly or housing, including upon servicing. They provide a secure joining and avoid fastener loss or damage that might be caused by a loose part.
Captive screws are often made with thread locking, press-fitting, or broaching to accomplish an anchor-hold within a larger assembly housing. However, a captive screw may also be melded with the material into which it is joined, either through cold forming or welding. Ever Hardware provides custom-made fasteners and customizable packaging.

Galvanization, or galvanisation, (or galvanizing as it is most commonly called in that industry), is the process of applying a protective zinc coating to steel or iron, to prevent captive screws rusting. The most common method is hot-dip galvanizing, in which parts are submerged in a bath of molten zinc. Galvanizing protects in three ways:
It forms a coating of zinc which, when intact, prevents corrosive substances from reaching the underlying steel or iron.
The zinc serves as a sacrificial anode so that even if the coating is scratched, the exposed steel will still be protected by the remaining zinc.
The zinc protects its base metal by corroding before iron. For better results, application of chromates over zinc is also seen as an industrial trend.
Hot-dip galvanizing is the process of immersing iron or steel in a bath of molten zinc to produce a corrosion-resistant, multi-layered coating of zinc-iron alloy and zinc metal. While the steel is immersed in the zinc, a metallurgical reaction occurs between the iron in the steel and the molten zinc. This reaction is a diffusion process, so the coating forms perpendicular to all surfaces creating a uniform thickness throughout the part.