What would justify the use of serrated blades in edged weapons?

Question

It's a reasonably common trope for characters to use serrated axes, swords, scythes, or similar weapons. Aside from trying too hard to look cool, are there circumstances where a serrated blade would be more effective than a conventional blade?

Three main considerations come to mind, but I may be making false assumptions:

1. A serrated edge will leave wider and more jagged wounds, causing additional pain, bleeding, and risk of infection.
2. Serrations would be more difficult to manufacture.
3. Serrations would be very difficult to sharpen.

I would expect this kind of blade to be ineffective against armor, but edged weapons generally aren't so hot under such circumstances anyway.

I'm thinking of forged weapons, not natural, though many animals have roughly serrated claws or bills, and teeth are more-or-less serrated by definition. Is this because it's difficult for a living thing to develop a very sharp edge like a human smith can with metal and a grindstone?

Answer 1

The Aztecs used Obsidian "Swords" which were effectively clubs with shards of sharpened obsidian embedded all down the sides to form a double-edged serrated blade. Given how sharp obsidian is, they made a very effective weapon! That said, like you have pointed out, such weapons are awful against armour — this is one of the things that led to the victory of the horribly outnumbered Conquistadores (that and smallpox).

The advantage here is that they could create a blade without having to use metallurgy (or indeed any knowledge of metal work) — the pieces of obsidian could be added individually without any forging process and could easily be replaced when a single "tooth" broke. Such a blade would be useful for someone who doesn't want to rely on the skills of a blacksmith to maintain or create a serviceable weapon.

P.S., technically, this doesn't meet your pre-requisite of "Forged", but I'm assuming from the context that you mean "man-made" as opposed to created using the forging process.

Answer 2

While this is slightly tangential to your question, a somewhat common real-world use of serrated edges on weapons is the back edge of many tactical / survival knives.

This serrated edge is not (generally) intended for combat, but rather to add functionality for non-combat uses - cutting wood for palisades, stakes, firewood; among other uses. While not necessarially more effective for combat, this does make the blade more effective as a tool.

This type of serrated back edge could also be usefull on something a bit bigger like a machete, designed as a tool for cutting through jungle, but perfectly servicable as a weapon.

To address your point about serrated vs straight edges on animals:

• Many animals do evole fairly straight, sharp edges - see beaks.
• Predatory animals have a slightly different use-case for their natural weapons then that which human weapons are designed for. Animals generally kill one thing, then eat it. This means that having your weapon (teeth / claws) get briefly stuck in your target is less dangerous then if you were a soldier on a battlefield. Serrated teeth are also better at cutting flesh when eating it.

Answer 3

Most of the answers focus on sword or knife-like weapons, used to slash or stab. In those cases, a serrated blade does a lot of damage to skin; instead of a clean (or mostly clean) slice, a serrated blade would tear, rend, and shred any skin it passed by. If your sole goal is to make a ragged bleeding mess of anything you stabbed, and you are willing to take the extra cost of sharpening each serration, a serrated sword vs. a 'normal' sword probably wouldn't be much different, apart from the shape of the wounds caused.

However, more damage comes at a cost; stabbing someone with a thin, straight blade will take a lot less effort than stabbing someone with a serrated edge, doubly so if they are in any sort of armor. Even thick clothing would make a serrated edge less effective.

However, there are other uses for serrations; a special, very strong knife with (dull) serrations on one side, known as a sword-breaker, was used as an off-hand weapon, to catch and twist the sword of your attacker. These weapons could snap the blade of a sword that is caught by it. Occasionally serrated barbs were also added to shields, for much the same purpose.

Serrations on an axe or hammer may actually improve the weapon, though it would be easier to use a spike. The serrated edge would carry the force of the weapon strike through a much smaller surface area, possibly resulting in poking holes through the armor. Of course, sharpened serration would be quickly dulled, and prone to break off, which is why most hammers used a single sharp spike to pierce armor.

Answer 4

In combat? Nothing, (though Bowls comment about causing damage from removing a weapon makes sense) there are no combat scenarios where a serrated blade is more useful than a non-serrated blade.

Serrations exist to give you more cutting edge so that you can keep an edge longer and were primarily developed for cutting wood.

To effectively use serrations in combat you would have to pull the weapon along your target. This would be completely useless against armor...even if that armor was wooden. Even against heavy fabric serrations would be less effective than a standard slashing blade (katana for example).

In short you would get more blade contacting the target using a standard edge when compared to a serrated edge.

Hold still I need to saw through your protective gear! -- unknown (He died)

Additional note: Having recently picked up forging as a hobby and having started on knives...I can tell you that the grinding/polishing/sharpening process is lengthy and time consuming.

Creating serrations would be even more difficult and the lack of benefit would lead to it being a style choice for the wealthy and not worth the time for mass produced army blades.

Answer 5

They could be used as weapons for intimidation that double as torture instruments. In this context, an evil soldier/secret policeman of some kind would press the serrated edge against a victim's face and then start rubbing it back and forth, or talking about doing it.

This would negate their ineffectiveness against armour - they're not intended for combat against somebody in full plate armour, but to scare people into obedience, which would exploit your first point.

Answer 6

A serrated blade will definitely cause much more damage than a straight blade. On a knife is one thing, but when you put this on a sword that you are using as your main weapon, the serration can actually be a deterrent.

All those serrations make it much more difficult to remove the blade once inserted. All those teeth are resisting removal and grabbing flesh and bone and armor and cloths. So once you stick someone you need to get the blade back out to fight the next person trying to remove your head. spending 5 minutes trying to get your weapon free is going to reduce your chances of survival.

Added: one justified use, might be some creature that has very tough skin and is difficult to kill. So you stick as many of the serrated blades into its body to kill it, if it pulls them out, it does even more damage to itself.

Answer 7

Pros - While Serrated blades are really hard to sharpen, but also very hard to dull, and having a chink knocked in it or a tooth knocked doesn't make the weapon any less threatening or dangerous. They're better against leather armor, cloth, rope and organics, like vines, wood and hide. They're better against straight-edged blades, which dull during impact swordplay, and depending on the style of serrations, could actually catch other blades.

Cons - Serrated blades can be more dangerous to the wielder simply because they're generally more dangerous. They require different sheaths than straight-edge blades. Once entering flesh or other organic material, they're hard to retrieve, so they're best if they're considered a consumable. This could be arrowheads, throwing daggers, one of many swords on hand, javelin points, et cetra

Answer 8

Realistically a continuous edge is better as weapon. Thus the starting point should be thinking about the drawbacks of a normal edge that a serrated edge doesn't have and under which circumstances they would be relevant.

Amount of metal

Before metal working people made weapons using microliths. This means attaching small pieces of stone worked to have a suitable edge to properly shaped piece of wood to form a weapon that is larger and more massive than can be directly made from the brittle stone and with sharper edge than wood can hold.

The stereotypical example is Aztec macautl, which used its large mass to make the edge effective in combat and allowed users to replace broken obsidian blades without replacing the whole weapon. This made sense since Aztecs didn't have a non-brittle material to make large weapons from. I expect they could have made copper maces, if they had wanted to, though.

So if your "cutting edge" material is expensive or brittle (or otherwise has limited endurance), you might want to use this construction and naturally end up with a serrated edge. Similar factors do apply to improvised weapons.

This is not sufficient to answer your question by itself, but should be added in as a factor to give some depth and historical background. Details like this make settings feel richer.

You don't need the weapon to be efficient

Armor penetration is not important if your expected opponents do not wear armor. Historically people had different weapons for use during wars against soldiers with armor and during peace against people wearing normal clothing. The latter category then further split to have different weapons to be carried for self-defense and for use in formal situations such as duels and sport.

So the first constraint would be that it probably isn't a military weapon. And more probably it isn't self-defense weapon either as such should be simple and efficient. A self-defense weapon that needs extra maintenance or fiddling so that you never quite keep it in top shape is a bad thing. That leaves formalized combat in duelling or sports. The line between the two is not always clear.

In such formalized combat leaving large messy cuts that are clearly visible to spectators, scar messily and hurt a lot would be beneficial. At the same time single hit kills or maiming is not really desired. A serrated edge can be built so that it cuts efficiently if messily to certain depth but then essentially becomes a blunt edge when cut depth exceeds the height of the teeth. Further you can easily cover the serrated edge with "antiseptic" material that ensures the cuts visibly scar and hurt enough to incapacitate recipient, but are unlikely to get infected.

This may seem unlikely, but the Aztecs mentioned earlier mostly warred to get captives to sacrifice to their god. Such wars were formalized enough for both sides to accept a less practical weapon that gets prisoners instead of casualties. Similarly Roman gladiators started as a religious ritual and gradually transformed to entertainment. They successfully used lots of "impractical" weapons. And not only was watching gladiators massively popular, people actually voluntarily participated in the training and even matches. In Germany they had an academic sport based on cutting each other in the face with a blade that makes shallow cuts. Such duelling scars were then a mark of honor to the bearer. A more full-body version could use a serrated blade.

In all cases you should include the historical connection to the microlithic weapon construction mentioned before to explain why this particular weapon is the proper traditional one that honors the gods and ancestors.

Answer 9

Sawback Bayonet

The German army discontinued use of the sawback bayonet in 1917 after protests that the serrated blade caused unnecessarily severe wounds when used as a fixed bayonet.

The story goes that if anyone was captured with a serrated bayonet they would be killed on the spot, so they filed them down before going into combat.

Answer 10

Does a flamberge count as serrated? Their blades were undulating which apparently had two applications; parrying an undulating blade causes vibrations in the parrying blade, slowing any counter attack. Secondly the flamberge was used to destroy halberds; the serrated blade was useful for dragging across the wooden shaft to saw through them.

Answer 11

This depends in part on what serrated really means. If we're talking about 'fantasy serrations' where the edge has enormous teeth,... I'll leave that to other posters. I'll add that knobs, fantasy spikes, protrusions, bumps, and similar doodads get hung on things.

As an alternative to fantasy serrations, consider "Damascus" steel. This is steel that is made by repeated folding and forging different metals until they weld and bond together. This gives an alloy that is intended to have positive attributes of the original metals. So, say we have a Damascus sword. When sharpened, you get a nice edge. Why not, at least one of the metals is iron. But the sword is still made of different metals and they will wear at different rates. The softer metals wears away during the final stropping. Now you have an edge that's serrated on the microscopic level. And this is the edge of legend. So against soft targets wearing cloth or leather, the sword is a meat saw - the serrations focus the energy of the blow and cause disproportionately severe wounds. And like a steak knife, the cuts are very clean. No energy is wasted. But against hard targets, the edge is retained due to the tougher steel. It is no wonder the ancients though such blades were magical.

To address your points:

1. (leave wider and more jagged wounds...) Deeper but cleaner.
2. (Serrations would be more difficult to manufacture) Yes, it takes a ton of know-how and effort to successfully create Damascus steel.
3. Serrations would be very difficult to sharpen. No, normal sharpening would do.

Answer 12

Serrated blades are different from swords for reasons. First off, swords are for slashing or stabbing, two actions which occur at high speed. This enables the blade to efficiently wedge through the material (i.e. a clean, quick, cut) because the swinging builds up more momentum that can be sustained in the slice. The serrated blade doesn't do very well with clean cuts, since instead of one edge, it has lots of tiny peaks, making the cut energy unfocused; plus, a large fraction of the cutting is being done by the trough between spikes. (This creates a more gruesome, potentially advantageous effect, especially when stab-sawing.) It's not very useful against armors, unless you had time to actually saw through it, which could take hours. A smooth sword, given enough power, is able to cleanly slice through many materials. Serrated swords also aren't very strong; the small (relatively) joint from the protrusion to the body of the sword isn't exactly immune from twisting, or maybe even bending. Perhaps it could double as an axe-sword, but then you limit the user to only one side for swordfights, which is a serious disadvantage.

Answer 13

Misconceptions

Serrated edges does not cut better, actually they cut worse. They saw better, but in combat you don’t have the time for sawing through anything.

You can try yourself with two knives of similar mass and weight distribution, one serrated and one properly sharpened (be careful though).

Surely you can kill someone with a serrated blade but it's still harder. And surely you can inflict fringed wounds (which are worse to heal but not really more deadly for short term periods), but your weapon it's going to stack everywhere, making that quite dangerous for you unless it's a throwable weapon like arrows and javelin.

Against armour

Against cloth armours like gambesons a serrated blade it’s really a bad choice because it will almost always remain stuck and will probably not cause a lot of damage anyway in the process of remaining stuck.

A serrated blade would actually be a little better against plate metal armour because it should bind better instead of glancing, transferring more blunt force. But the majority of bladed weapons like sword doesn't have enough mass on the tip for being useful as blunt weapon no matter if normally sharpened or serrated, that's why in late middle age martial art has being developed the mordhau technique for combat in armour, which consist in grabbing the sword by the blade and use the guard and pommel as the head of a mace/warhammer.

Maibe an axe (or a falcata) can benefit by serration against plate metal armours, but a mace or warhammer would still be a lot better for this task, and a normal axe would be better against flesh and fabric armours (A lot of medieval pole weapons had 2 separated heads: an axe and an hammer) So there are no reasons for it.

Parrying daggers

Deep serrations has been used in parrying daggers, commonly known as “sword breaker” (a term that should be substituted by “sword catcher” since it's almost impossible to break even a low quality sword that way, at the very most you can bent it since it’s metal not ceramic), you can't put such protruding serrations on a longer blade without making it too weak or too heavy, and you don't want to use it alone but always with another weapon because if you catch your opponent blade then your parrying dagger is also stuck and not usable for offending.

So what else? Maybe trust/bind oriented swords

We have established that serrations are actually useful on blunt weapons (not edged), parrying weapons and missiles.

What about bladed offensive weapons?

We have said that serration decrement the cutting power so we have to exclude more cut oriented weapons like sabres/scimitars.

It's probable that even a shallow serration would increase the friction between two blade during a bind, allowing for better controlling your opponent’s blade (but I don't know if it's sensibly better than a normal proper sharped blade for practical purposes). So maybe we can use it for defensive purposes (not offensive) in trust oriented weapons that are used in a martial art focused on bindings like in HEMA, such weapon can be the rapier.

Rapier can also cut but its usage was heavily trust oriented as opposed to their predecessors like sideswords and armingswords, which also tend to prefer trust over cut but to a less extend. Rapier also eventually evolved in smallsword that was completely blunt due to its triangular section.

So i assume putting serration on a rapier shouldn't really decrease by much its offensive effectiveness, maibe would be better to leave the weak of the blade normally sharpened since you don’t want to parry with it anyway and you will use it for small quick cuts.

Putting serration on blunt swords like smallsword and estoc don't detract noting but also don't add nothing usable in the context those weapons were used (the first was a duelling sword and the second specialized for fighting in armour).

Also actually a good serration that is sensible better for bind control and dont weak the blade can potentially be puted on the strong of the true edge and on strong and medium of the false edge of basically every sword without actually impair their cutting capabilities for practical use in combat, at the same time improving a bit the parring effectiveness since you want to parry with the strong and cut with the medium and weak.

Anyway I have historical records of serration only on the false edge of more recent swords used more like a tool/weapon hybrid. Probably it’s not that much of an improvement for combat compared to crafting, maintenance and tradition issues.

Sources: I'm an hema practitioner and enthusiast, and i follow different related youtube channels and blogs. I suggest Scholagladiatoria and Shadiversity over others.

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For what concern claws and teeths they are not meant for slicing but for trapping the prey. Even if nature can create something sharp like a sword there’s nothing in common between how an animal use its jaws and how we use a saw or a sword. With saws and swords you make forward-back movements in order to slice, with jaws you crush things opening and closing or rip flesh keeping close and pulling with movement of the head.

Answer 14

Simple; more surface area on the blade. Minimum surface area when hit (increasing PSI), increasing surface area while "burying". Plus slice damage.

Answer 15

Why does anyone use a serrated blade? I bought a serrated pocket knife for cutting up boxes and cutting paracord. For cardboard it lets you "saw" through the material.

I've seen serrated steak knives, not as cheap ever-sharp knives, but in a high quality design. The serrations are of a particular shape that have the effect of protecting the sharp part when it bottoms out on the hard plate, rather than mashing down the cutting edge.

So is any of this useful in combat? It might have to do with the type of defensive armor, uses of the blade other than against skin, and fighting techniques.

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I just saw some advise to use a serrated knife when slicing a tomato. This is an echo of this general reasoning: it’s suitable to the skin or armor or equipment that you intend to cut. Killer tomatoes are known to attack, and a serrated blade is recommended specifically in this case.

Answer 16

Serrations would reduce combat effectiveness for up-close melee fighting.

First, manufacturing a serrated combat weapon, as noted by many of the other answers, would take more time and money to produce. This means fewer weapons or more weapon smiths and higher costs.

Second, maintaining the weapon would require more effort and time. Each serration would require sharpening and would be more effort than, say, a sword or ax head of the same length.

Third, pointy bits break easier. Those serrations produce weaknesses. While in combat, a weapon is often forced to serve as both defense and offense. So while blocking your opponent's blades, those serrations would break easier than a straight, solid, blade. They might even provide a stress point for stress cracks and breaks after enough bashing against things.

Fourth, pointy bits get stuck. Those serrations snag on things. This is why they do more damage. But this means extracting the weapon from your opponent or his shield or his armor will take a fraction longer than a smooth blade would take. And the serrations are more likely to get stuck in ribs or other bones. The extra effort and time required to retrieve your weapon from your victim means your victim's buddies have more time to take you out before you're ready to face them.

That one is where warriors would probably build a hatred for the serrations. They see their buddy die because his blade got stuck in someone's ribcage and they're like, "Nope. I don't need that."

Fifth, weight. You are adding "triangles" to your sword. Those triangles add extra weight to the sword/ax/thing. This means it will swing and recover more slowly in close fighting.

Serrations might improve combat effectiveness for pole-arm and ranged fighting.

Serrations on an arrow head or spear head (when spears are thrown) means they're harder to remove from your wounded buddy and do more damage coming out. Therefore, they're more useful in these scenarios.

Likewise, a pole-arm might be more effective with serrations for the same reason; especially if intended to resist cavalry.

These are both situations where the weapon has no defensive purpose and is not intended for close, fast, fighting.

Answer 17

The best use for these weapons might be to make your own army look scary, for a negative effect on the morale of the enemy.

The effect of witnessing their fellow soldiers getting ripped to bloody shreds and the thought that not just might they be killed, but killed in a horribly painful way might make them worry a bit.