Overview

• Flat head fasteners have flat surfaces that taper toward the screw body to allow for countersinking
• The flat head lies flush against the workpiece
• Slotted drive types are used with flat-blade drivers
• They have one linear slot that runs the length of the head
• Drivers must be centered in the slot during tightening or they will slip out and damage the fastener
• Steel is strong and durable but less corrosion resistant than stainless steel
• To improve its resistance to corrosion, it may receive additional finishes and coatings
• Type A screws have sharp points and coarse threads
• They are used to cut threads in drilled or punched holes in thin sheet metal.