Overview

• Internal tooth washers have serrations on the inside diameter that grip both the fastener and workpiece to lock into place
• Pan head types have cylindrical heads with rounded edges and flat bearing surfaces
• Their low head height and large diameter provide increased driving power
• 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.