Serrated blade

A serrated blade has a toothlike rather than a plain edge, and is used on saws and on some knives and scissors. It is also known as a dentated, sawtooth, or toothed blade. Many such blades are scalloped, having edges cut with curved notches, common on wood saws and bread knives.

With kitchen knives, the finer serrated edge is found typically on paring and cheese knives, particularly for slicing harder cheeses like cheddar or Wensleydale. The wider scalloped-edge serrations are found on practically all bread knives and typically on fruit knives. These serrated knives are better able to cut through a firmer or tougher outer crust or skin without crushing the softer and more delicate inner crumb or flesh.

Serrations give the blade's cutting edge less contact area than a smooth blade, which increases the applied pressure at each point of contact, and the points of contact are at a sharper angle to the material being cut. This causes a cutting action that involves many small splits in the surface of the material being cut, which cumulatively serve to cut the material along the line of the blade.

Cuts made with a serrated blade are typically less smooth and precise than cuts made with a smooth blade. Serrated edges can be difficult to sharpen using a whetstone or rotary sharpener intended for straight edges but can be sharpened with ceramic or diamond coated rods. Further, they tend to stay sharper longer than similar straight edges. A serrated blade has a faster cut, but a plain edge has a cleaner cut. Some prefer a serrated blade on a pocket knife or on an emergency rescue knife, especially with the latter for its increased ability to cut through cords, ropes, and safety belts.

Types of serration

 * Tooth serration — Vertical serration along edge of blade
 * Single edge serration — Serration on one side, the other remains flat
 * Double edge serration — Serration on both sides
 * Fan serration — Side-to-side serration without necessarily having a toothed edge
 * Micro-serration — Serration much smaller than thickness of blade creating something like a fan pattern