Story and Photos by Michael Janich
When I teach seminars in my system on knife self-defense – Martial Blade Concepts (MBC) – I tend to get a lot of the same questions from my students.
By far one of the most common questions they ask is “What type of edge is best for a personal defense knife – plain, fully serrated, or 50/50?” Like most equipment choices, it ultimately boils down to a matter of personal preference. However, there are some solid guidelines that can help you decide what’s best for your personal needs.
First of all, let’s assume that we’re talking about a dedicated personal defense knife – not one that will be used for utility purposes, or even do double duty in both roles. We’re concerned with pure combative use. Also, as far as I’m concerned, we’re only talking about true, committed cuts.
I know that some edged-weapons instructors advocate tactics with serrated edges that are based on raking or “scaling” exposed skin, but I’m not in that camp. If you are using a knife in a fight, you have crossed the legal line into the application of lethal force. That should only happen if you are in real fear of death or grievous bodily injury. As such, you should be trying to stop your attacker decisively, not just inflicting arbitrary pain in the hopes he’ll quit.
With all that in mind, our goal is to choose an edge that cuts as efficiently as possible in the context of typical defensive applications. That means something that cuts tissue effectively, but more importantly, something that will power through typical clothing and still have telling effect on the anatomical targets underneath.
I evaluate edge performance in this context with a target I call “Pork Man.” It consists of a raw, 4-5-pound pork tenderloin or roast that I butterfly and tie around a wooden dowel with butcher’s twine. I then wrap the roast with about 20-30 layers of plastic kitchen wrap and “clothe” it with a denim pant leg, a jacket sleeve, or something similar. This provides a consistent simulation of tissue, bone, tendon, skin, and clothing – as well as a medium for reasonably empirical cutting tests.
I have used this type of target for almost 20 years in my seminars, in formal knife testing for magazine articles and in my own research. I’ve done thousands of cuts on hundreds of Pork Men using all types of knives and edge configurations. That live-blade cutting experience is the basis for my observations and opinions.
Let’s take a look at each blade style on its own merits.
Full SerrationIn simple terms, full serrations have the advantage of packing more cutting edge into a given blade length. They also provide an aggressive “interrupted” cutting action that is very much like cutting with a saw – the various facets of the edge cut, disengage, and cut again as the edge is drawn across the target.
In most cases, this saw-like action cuts very aggressively and makes short work of fibrous materials – including things like clothing. However, to cut effectively, the material being cut must be stabilized well. If it is loose and moves easily, the serrations can grab the cloth and move it with the cutting motion, producing minimal damage to the material and the real target underneath. Against loose clothing and multiple layers of clothing – both popular fashion statements among criminals – cuts with a serrated knife may be ineffectual.
50/50Combination or 50/50 edges typically have a section of serrations near the heel of the blade (the section of the edge closest to the handle) and a plain cutting edge closer to the point. In theory, this style of edge provides the best of both worlds.
With a good cutting technique that starts at the heel and uses the full length of the blade, it bites aggressively and finishes cleanly. Even if the serrations do cause the clothing to slide or spin, as the cut progresses and the plain edge takes over, it cuts cleanly.
In practice, this theory holds up pretty well, but is very dependent upon the style and pattern of the serrations. From a maintenance standpoint, it also makes life a little more complicated. Sharpening serrations can be challenging. Sharpening a blade that includes both a section of serrations (which are usually “chisel” ground on only one side of the blade) AND a section of plain edge (which is normally double ground from both sides) is even more challenging.
As the blade wears from repeated sharpening, the efficiency of both sections of the edge can become compromised and eventually the two “blur” a bit.
With that said, for many years one of my daily carry knives – specifically my “back pocket” knife – was a 50/50 Spyderco Delica. I included it in my carry kit primarily as a utility knife and specifically to cut fibrous materials like rope and seat belts. As a defensive knife, it was a back-up, not a primary weapon.
Plain EdgePlain edges have no serrations whatsoever. That means that they will not “grab” clothing. But it also means that they must be properly sharpened, have good edge geometry (the angular cross section of the bevels and cutting edge) and cutting-edge profile to cut efficiently.
If all those qualities are present, in my experience, the plain edge will cut deeper and more aggressively than either a fully serrated or combination edge. If those qualities are not present, plain edges can skate over material without biting. That’s why good practitioners of knife tactics must also understand cutting dynamics and know the difference between a truly sharp edge and one that isn’t.
With all this said, we also need to remember that – like knives themselves – not all serrations are created equal. Some manufacturers understand serrations and do them well. Others don’t, and the performance of their knives shows it.
Also, some companies use serration patterns that can be easily maintained and offer a long service life. Conversely, others use serration patterns that cut well initially, but are less durable over time and very difficult to sharpen once they become dull. The grind of the blade bevels and the profile of the cutting edge also have a huge influence on the cutting performance of a blade and can either enhance or detract from the performance of the edge “style” you choose.
Based on my cutting tests and extensive field use of many different serration styles, I prefer Spyderco’s serrations to those of other manufacturers. They were the first ones to incorporate serrations into folding knife design and, in my opinion, still do it best.
Cold Steel’s serrations – which have much smaller teeth than those of other manufacturers – cut very well initially. However, their smaller teeth make them somewhat more prone to chipping. They are also more challenging to sharpen. Although Lansky makes a pocket sharpener specifically for Cold Steel’s serrations – using it is a time-consuming process.
My least favorite serrations of any major manufacturer are those of Benchmade. They only offer partially serrated blades and the way they cut their serrations sets them back (higher toward the spine) from the plain portion of the edge. In my experience, they don’t cut as effectively and the transition point from the serrated section to the plain-edge section tends to snag. They also shorten the working lifespan of the blade.
Ultimately, the only way to determine which edge works best for you is to test your preferred knife with all three edge choices (all in perfectly sharp condition) on identical targets and evaluate the results for yourself. I understand that may not always be practical, affordable, or even possible. That’s why I hope the general guidelines provided here will help point you in the right direction.
Serrations definitely have their place, but for defensive use, I feel a properly sharpened plain-edged blade with good edge geometry is the best choice.
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One of the other logical questions I get with regard to serrations is, “How do you sharpen them?” The answer depends again upon the style of the serrations.
For most well-designed serrations – like those from Spyderco – the answer also comes from Spyderco: the Spyderco Sharpmaker.
I’ve been sharpening knives for about 40 years and have an entire box full of stones, clamps, and other gadgets that are supposed to take the mystery out of the process so anyone can do it. Somewhere in the middle of that time, I discovered the original Crock Stick – two ceramic rods that fit into a wooden base.
Instead of having to develop the muscle memory to hold a knife at a precise angle while dragging it across a stone, all I had to do was keep the plane of the blade vertical and draw it alternately along each ceramic rod. The angles of the rods automatically set the sharpening angle for the edge and life was good – unless you had a serrated edge.
The Spyderco Sharpmaker takes the concept of the Crock Stick and makes it better by using triangular stones with rounded edges. By using a slightly loose grip, the drawing stroke allows the edges of the stones to “flow” down into the concaves of all the serrations. Unlike plain edges, which use an equal number of alternating strokes on each side, serrations are sharpened with three strokes on the bevel side and one on the non-beveled side.
The Sharpmaker works on just about all serration patterns – except for very small-toothed serrations like those found on many Cold Steel knives. Cold Steel’s serrations are actually best sharpened by treating the non-beveled side as a plain edge and using the flat of the right Sharpmaker stone. Eventually, you’ll hit a point of diminishing returns, but this technique will keep Cold Steel serrations sharp for a good, long time.
Nine-year veteran of the U.S. Army Intelligence and Security Command, Michael Janich also served a 3-year tour at the National Security Agency. Highly decorated, Michael is a two-time graduate of the Defense Language Institute and served around the world in intelligence and investigative capacities for many years. Utilizing his extensive training in various martial arts and military/LE combatives, he established Paladin Press’ Video Production Department in 1994, running all aspects of video production for 10 years – personally recruiting some of Paladin’s most popular authors and being selected to work with the late Col. Rex Applegate as the producer of his landmark instructional videos on handgun point shooting. Published book and magazine author, Michael has been featured on various television programs and designed knives for many different knife companies throughout the industry. Michael is the founder and lead instructor of his signature knife defense program, Martial Blade Concepts.
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