Editing Blade (section)

===Geometry===
[[File: Whale knife hg.jpg|thumb|Blade of a whale knife]]

The angle at which the faces meet is important as a larger angle will make for a duller blade while making the edge stronger. A stronger edge is less likely to dull from fracture or have the edge roll out of shape.

The shape of the blade is also important. A thicker blade will be heavier and stronger and stiffer than a thinner one of similar design while also making it experience more drag while slicing or piercing. A filleting knife will be thin enough to be very flexible while a carving knife will be thicker and stiffer; a dagger will be thin so it can pierce, while a camping knife will be thicker so it can be stronger and more durable. A strongly curved edge, like a [[talwar]], will allow the user to draw the edge of the blade against an opponent even while close to the opponent where a straight sword would be more difficult to pull in the same fashion. The curved edge of an axe means that only a small length of the edge will initially strike the tree, concentrating force as does a thinner edge, whereas a straight edge could potentially land with the full length of its edge against a flat section of the tree. A splitting maul has a convex section to avoid getting stuck in the wood where chopping axes can be flat or even concave. A [[khopesh]], [[falchion]], or [[kukri]] is angled and/or weighted at the distal end so that force is concentrated at the faster moving, heavier part of the blade maximizing cutting power and making it largely unsuitable for thrusting, whereas a [[rapier]] is thin and tapered allowing it to pierce and be moved with more agility while reducing its chopping power compared to a similarly sized sword.

A serrated edge, such as on a [[saw]] or a [[Kitchen knife#Bread knife|bread knife]], concentrates force onto the tips of the serrations which increases pressure as well as allowing soft or fibrous material (like wood, rope, bread, and vegetables) to expand into the spaces between serrations. Whereas pushing any knife, even a bread knife, down onto a bread loaf will just squash the loaf as bread has a low [[elastic modulus]] (is soft) but high [[yield (engineering)|yield strain]] (loosely, can be stretched or squashed by a large proportion without breaking), drawing serrations across the loaf with little downward force will allow each serration to simultaneously cut the bread with much less deformation of the loaf. Similarly, pushing on a rope tends to squash the rope while drawing serrations across it sheers the rope fibers. Drawing a smooth blade is less effective as the blade is parallel to the direction draw but the serrations of a serrated blade are at an angle to the fibers. Serrations on knives are often symmetric allowing the blade to cut on both the forward and reverse strokes of a cut, a notable exception being Veff [[serration]]s which are designed to maximize cutting power while moving the blade away from the user. Saw blade serrations, for both wood and metal, are typically asymmetrical so that they cut while moving in only one direction. (Saws act by abrading a material into dust along a narrow channel, the [[kerf]], whereas knives and similar act by forcing the material apart. This means that saws result in a loss of material and the serrations of a saw also serve to carry metal [[swarf]] and [[sawdust]] out of the cut channel.)

[[Fuller (weapon)|Fullers]] are longitudinal channels either forged into the blade or later machined/milled out of the blade though the latter process is less desirable. This loss of material necessarily weakens the blade but serves to make the blade lighter without sacrificing stiffness. The same principle is applied in the manufacture of beams such as [[I-beam]]s. Fullers are only of significant utility in swords. In most knives there is so little material removed by the fuller that it makes little difference to the weight of the blade and they are largely cosmetic.