Slotted Round Head Machine Screws
Zinc Plated Steel Round Head Screws
Slotted round head machine screws are ASME standards specific. These fasteners are installed with flat or slotted screwdriver. Round Head Machine Screws feature a domed top, similar to a button head but shaped more like half of a sphere. Slotted head machine screws are often used with nuts as well as driven into tapped holes. In practice, they tend to be mostly available in smaller sizes and the smaller sizes are referred to as screws, or less ambiguously as machine screws, although some kinds of machine screw can be referred to as stove bolts.
Zinc plated steel is very common in the fastener industry. Zinc adds a layer of corrosion resistance to plain alloy steel. Clear zinc has a light, shiny color and blue zinc has a bright blue hue. Zinc plated steel is not suitable for extreme environment use, as it is not as resistant to corrosion as hot dipped galvanized.