The Science behind Serrations

[00:00:00]Well, we're back with another one. So, I have a lot to say today. A lot has been on my mind about serrations again. I know, I know. Sergeant Serrations at it again. But, someone has to do it. I know there's a lot of people getting frustrated at me and my dang serrated edge videos, but we're back at it again stirring the smooth plain edge community up.

[00:00:23]So, where do I start? Most people think serrations are saws, but serrations spread material just like a plain edge, and saws remove material, hence wood shavings or sawdust. And if they don't think it's a saw, they think serrated knives are just plain edges with teeth.

[00:00:41]Well, kind of, but not exactly. A serrated edge is made up of many small cutting edges arranged into teeth and gullets. The front of each tooth is essentially a tiny plain edge, but the overall geometry is different because those edges are angled and separated by grooves.

[00:01:01]Um, a plain edge equals continuous a continuous cutting edge.

[00:01:07]Serrated edge equals multiple cutting edges connected by teeth.

[00:01:14]Saws have teeth and serrations have, well, serrated edges.

[00:01:19]I don't think that's quite a technical term, but it's as close as I can get to that.

[00:01:24]Um, a serrated edge uses physics differently than a plain edge, and that's why it can keep cutting long after a plain edge starts struggling.

[00:01:35]Today, we're going to look at the science behind serrations and find out why they work so well on rope, webbing, cardboard, and other tough materials.

[00:01:45]>> [snorts] >> Uh, what is a serration? Um, when you look closely at a serrated edge, you'll see a series of peaks and valleys. Those points concentrate force into a much smaller area than a plain edge. Since pressure equals force divided by area, the smaller the contact area, the higher the pressure at the point of contact. So, this is a double serrated edge.

[00:02:12]This is a single serrated edge.

[00:02:16]Uh we'll get into that a little bit later, but I'm getting off subject again.

[00:02:21]Uh that concentrated pressure helps the edge bite into material quickly instead of simply pushing against it.

[00:02:30]Imagine 15 knife tips, basically like this, uh scraping on the material.

[00:02:37]So, why serrations excel on fibrous materials in the first place?

[00:02:43]Materials [snorts] like rope, tow straps that we always cut, uh webbing, uh cardboard, all those are made of uh thousands of tiny fibers. A plain edge usually has to push uh push through many of those fibers at once. But, you're not going to be really doing any the hence the push cut. You're not going to be really doing any push cutting with layers upon layers. You're still forced to do a sawing action to get through. And if you say do a slicing action, well, you might as well just do a sawing action to begin with because you're kind of getting more cutting power in a sense.

[00:03:21]So, a serrated edge um attacks them differently. The points grab the material while the curved sections um slice individual fibers apart. Instead of one long cut, the knife is making many small cuts at the same time.

[00:03:39]Also, giving you more control because you you get to feel the cut almost like a saw on wood, if that makes sense.

[00:03:49]This grabbing and slicing action is why serrated knives often feel more aggressive when cutting rope.

[00:03:57]But why do they keep cutting when dull?

[00:04:00]That's a big question a lot of people ask. Um here's where things kind of get interesting. On a on a plain edge, the entire cutting edge is basically exposed and it wears basically somewhat evenly.

[00:04:14]Um once it gets dull, performance drops noticeably almost immediately for me anyways. And it's truly it it truly doesn't take that long in a in a day's use. Um ever skin a game animal? Well, you'd know your plain edge is dull halfway through. Uh maybe even quarter way through depending on the game animal you're harvesting and skinning.

[00:04:39]Um with serrations, uh the points they they do much much of the work. Um the recessed cutting edges inside the valleys are protected from wear. Even after heavy use, those protected edges can remain surprisingly sharp. Uh we've tested these in in the long videos and the short video formats.

[00:05:01]I also believe the chisel grind helps a lot uh as well. Um that's one reason a well-used serrated knife can can can Sorry, [clears throat] I'm stuttering there.

[00:05:14]Uh can continue cutting effectively long after a plain edge would need sharpening. And yes, we're we're going to be skinning uh this year with the serrated knife and we will definitely report back the results.

[00:05:27]So, the true the true tradeoffs um for each knife, uh nothing is perfect.

[00:05:34]Serrations are incredible for fibrous materials, but they don't always produce uh the cleanest cuts.

[00:05:41]Um they can tear delicate materials like we've seen with uh leather. And they're usually more difficult to sharpen because, well, in my opinion, um, people just simply don't know how to sharpen.

[00:05:54]And the serrated knife is, to me, a lot easier to sharpen once you know how. So, if you're preparing food or doing delicate, uh, detailed carving or maybe skinning, a plain edge is often the better tool. I say maybe because, well, we like to do hand-on tests to verify instead of going by the knife community book. So, the conclusion to all of this, um, are serrations better than plain edges?

[00:06:26]Well, not necessarily. They're different tools designed for different jobs. But, when it comes to rope, webbing, cardboard, and other fibrous materials, um, the physics behind serrations give them a real advantage. And we've seen that, um, even feather sticking and other jobs the whole knife community says plain edge is better at.

[00:06:49]Um, but my tests have proven that serrations are better, uh, uh, it's a better tool for these tests, um, it's we're we're hands-on. We're not basically going from the book, is what I'm trying to say.

[00:07:03]Uh, also a double serrated edge, like this one you see, um, cuts better on on fibrous materials over a single, uh, serrated edge because it creates more points of pressure and more cutting edges instead of having one large, uh, serration or one or one, uh, small serration.

[00:07:26]Um, it's it's separated the the gullet, not not the gully. Uh, that's another thing I'm going to be talking about because, uh, in knife terminology, gullet is actually the correct term for the valley between serration uh, teeth. It's bor- it's borrowed from saw tooth terminology.

[00:07:49]Where the gullet is the space that helps clear material and separates the cutting points.

[00:07:56]Some people casually say gully and I have basically the whole time, but because it sounds like a small valley and the meaning is easier to understand, but if you're discussing serration geometry, sharpening, or knife design, >> [clears throat] >> gullet is a proper technical term.

[00:08:16]Now I'm getting off track a bit and I'm starting to maybe get too technical, but some of my friends here that comment are really starting to make me pick up my socks. So you So you know you you know who you are, MB Magic, but anyways, [clears throat] appreciate you. You're always correcting me if I'm wrong or just simply providing the right information for everyone. Uh that you know, that that that that that goes a long ways and I'm never too old to learn and well, neither are you. Um but I'm I'm getting off track again.

[00:08:53]Uh a double serrated um pattern adds smaller serrations between the larger ones. This means more teeth are engaging the material at once, incre- increasing the number of fibers being cut during each stroke. The extra points also help the blade grab slippery materials like rope, webbing, [snorts] cardboard more aggressively. The result uh The result is often a smoother cut, less snaggy, faster penetration, and improved cutting efficiency, especially [snorts] when using a slicing motion.

[00:09:31]The trade-off is that a double serrated edge can, I guess, be more difficult to sharpen than the single serrations, but with the right tool I find them easier than a plain edge still.

[00:09:43]Uh well, that talking script might have got out of hand a bit, but let me know if you like this kind of informative videos and what's really on my mind is is how [snorts] tough a serrated edge is.

[00:09:56]The cutting force is concentrated on onto a series of small points instead of being spread across one long continuous edge. Each tooth acts like a tiny saw blade creating high pressure at the contact point, which helps it bite into tough fibrous materials, even small trees and vegetation.

[00:10:17]You do get a bit of a a cut on trees even up about half an inch before they start uh pinching, but the gullets between the teeth also provide space for material to move and spread as it's being cut, reducing drag and preventing the edge from slipping, hence control while you cut another Uh well, you get uh control like I said in earlier in the the script.

[00:10:42]Um Uh the the tips of the teeth uh contact surfaces during normal use, so much of the cutting edge remains protected from wear, allowing a serrated knife to stay effective long after a plain edge feels dull, and I mean a a really long time.

[00:11:01]Another thing on my mind is is the serrated edge is so underappreciated and basically hated on. I do understand because at one point I didn't understand them, and now I feel like a serrated messenger for YouTube, but my favorite knife's a plain edge and a big plain edge because you really need inertia to make a plain edge good uh along with premium steel. Serrations can uh get away with lower quality steels because of their strength. And we've seen that compared to that chippy S30V on the plain edge.

[00:11:35]Well, the serrations are still like new, uh which is very shocking.

[00:11:39]Let me know in the comments, are you team serrated or team plain edge? Oh, by the way, uh this Para 3 started this whole channel. It was a gift from my girlfriend.

[00:11:52]Um yeah, so this Para 3 started the whole channel, which is extremely shocking and pretty dang cool. Um if you enjoyed this you can you know you can always hit that like button. It's very much appreciated.

[00:12:04]And if you haven't subscribed, do me a solid so you don't miss out on future knife tips. That was kind of a pun. Uh also, my friend Hoosier makes those kind of jokes, so I had to return the favor.

[00:12:16]Appreciate all of you for uh watching. I I want to thank you. Um that one took a lot out of me, but it was fun. It was also nice to get that off my chest. Uh but anyways, Blade Basics over and out.