Blade

A blade is the sharp, cutting portion of a tool, weapon, or machine, specifically designed to puncture, chop, slice, or scrape surfaces or materials.

Serving as one of humanity's oldest tools, blades continue to have wide-ranging applications, including in combat, cooking, and various other everyday and specialized tasks.

Design variations, such as serrated edges found on bread knives and saws, serve to enhance this force concentration, adapting blades for specific functions and materials.

Blades thus hold a significant place both historically and in contemporary society, reflecting an evolution in material technology and utility.

For construction equipment such as a grader, the ground-working implement is also referred to as the blade, typically with a replaceable cutting edge.

It is this high pressure that allows a blade to cut through a material by breaking the bonds between the molecules, crystals, fibers, etc.

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 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.

For example, a steel axehead is much harder than the wood it is intended to cut and is sufficiently tough to resist the impact resulting when swung against a tree while a ceramic kitchen knife, harder than steel, is very brittle (has low toughness) and can easily shatter if dropped onto the floor or twisted while inside the food it is cutting or carelessly stored under other kitchen utensils.

[4] Prehistorically, and in less technologically advanced cultures even into modern times, tool and weapon blades have been made from wood, bone, and stone.

As non-metals do not corrode they remain rust and corrosion free but they suffer from similar faults as stone and bone, being rather brittle and almost entirely inflexible.

They are often serrated to compensate for their general lack of sharpness but, as evidenced by the fact they can cut food, they are still capable of inflicting injury.

Plastic blades of designs other than disposable cutlery are prohibited or restricted in some jurisdictions as they are undetectable by metal detectors.

Various alloys of steel can be made which offer a wide range of physical and chemical properties desirable for blades.

Steels can be further heat treated to optimize their toughness, which is important for impact blades, or their hardness, which allows them to retain an edge well with use (although harder metals require more effort to sharpen).

The ability of modern steelmakers to produce very high-quality steels of various compositions has largely relegated this technique to either historical recreations or to artistic works.

Acid etching and polishing blades made of different grades of steel can be used to produce decorative or artistic effects.

Dulling usually occurs due to contact between the blade and a hard substance such as ceramic, stone, bone, glass, or metal.

The resulting scratch is full of very fine particles of ground glass or stone which will very quickly abrade the blade's edge and so dull it.

Curved blades tend to glide more easily through soft materials, making these weapons more ideal for slicing.

For straight-edged weapons, many recorded techniques feature cleaving cuts, which deliver the power out to a point, striking directly in at the target's body, done to split flesh and bone rather than slice it.

Other weapons have a blade that is entirely dull except for a sharpened point, like the épée or foil, which prefer thrusts over cuts.