Combat knife design

LiamLynch

LiamLynch

Well-Known Member
Basically I am trying to design a knife that is used as a last resort (dare I use the forbidden word?) weapon. It is going to be a kind of standard issue type thing, a soldier wants a last resort weapon made and this is the first pattern I show him type thing. I want to know what kind of knives are most effective for defence. I understand that one will likely get more use out of a utility type knife but I should say that if I needed to use a knife to defend myself I would want one designed for the job. What I want to know is what do soldiers like, I know the usual full tang, micarta and kydex stuff but do you want a straight blade or a recurve, do you want finger rings or persuaders, tanto or not tanto, serrations or not, what finish? And what kind of accessories do you want with it, do you want locking sheaths or a survival kit type thing with it. Basically, what would be your perfect knife? I don't know any military personell so I can't ask them, if you are, or know soldiers can you help me out on this. Also because this design is to help military I will allow anyone who wants to copy it, if the design works then it is wrong to keep it to myself. Once I get enough to go by I will post up a picture and let you guys see what you would change. Thanks in advance. Thank you also for any military service, past present and future.
 
Kbars have killed a lot of people. other than them
spartan blade works, busse, and randall knives have some popular desings among soldiers, use them for references. post a pics of whatever you come up with if you have time.
 
I've built a few to specific requirements for law enforcement and deploying military. Here are some points that I have learned from a variety of sources, both print and first hand. I am not a serviceman but I have asked a great deal of questions and in no way want to come across as an armchair cowboy here.

-The knife is most likely going to be used as a tool at some point, sooner instead of later, to save time and allow that time to then be spent getting or staying safe. Guys get in a hurry with great justification as law enforcement or soldiers and anything goes. Prying, hammering, you name it. I've heard of knives being used to pry Humvee doors open and cut sheetmetal. I can't blame them, so I built everything for those applications as strongly as I can.
-They like a full tang. Being stronger or not than a hidden tang with a threaded pommel is arguable but the guys like to see steel all the way to the butt. I specifically either have bolsters at the pommel or run the tang proud of the scales a good 1/4" inch to allow the butt to be used for impact without splitting the scales off. Corby or Loveless fasteners are good.
-Points will be used to pry with and and if too thinly profiled, finely ground, or brittle will break. I grind to a thickness of about .060 at the edge prior to sharpening for the last inch or so of blade vs the .040 over the rest to give a little added thickness there. The Fairbairn-Sykes stiletto dagger is a dangerous weapon but won't last long in heavy usage.
-Length and blade width matters. To be perfectly blunt, you don't slice someone if you want to get it over with fast, unless you've got access to the neck. You stick them with it. At least six inches of blade is what I've heard to be a standard minimum, the Ka-Bar is seven, bayonets were historically even larger. You want to be able to get right into the boiler room with little effort on your first shot. Big 2" wide 5/16" thick blades are going to take a proportionally larger amount of "shove" to get deep versus a narrower blade, unless keenly pointed, but there are tradeoffs for the mentioned tool usage.
-The knife should have a guard. The last thing anyone using a knife under duress wants is to have their hand ride up onto the blade or have to be "careful" using it beyond a reasonable expectation.
 
Sorry I'm late to the game, I've been out of pocket for a bit.

First, as a soldier I can say that the average soldier does not use a knife as a weapon. A soldier's knife is a utility tool first and foremost. The design should lend itself to easy and comfortable use and should be easily maintained. The designs I find most favorable are ones of either a drop point or clip point variation. Both designs are easily sharpened. As for size, anything over 4-5" blade will likely be too cumbersome. My personal combat knife has a 7" blade and I have found that the only thing I have used it for is the "intimidation factor". I carried it every day and never used it. It was more convenient to use my pocket knife than a 7" blade.

Just my $0.02.
 
That's a good take on the size aspect there, Murph. As I went on about blade size I surely didn't mean that longer or larger is better...even smaller than the size of a traditional Ka-Bar, which is a large knife, something like 12 inches in total length, you're getting into real pigsticker territory where any detail work is going to be nearly impossible. The knife from what I've seen in a lot of those cases then becomes a thin, sharp, pointy and quite expensive crowbar 99 percent of the time, in a fancy sheath.
 
So, it wants to be reasonably thin, 4-5" blade (I'm going to listen to murph on this one, he's the soldier), bolsters to hammer with, for cutting sheetmetal would serrations be wanted? It sounds to me like the handle wants front and rear quillions for the most secure grip. It is my understanding that tanto blades have stronger geometry, would they be better for prying? I intend to join the marines and right now my thought process is that I would much rather carry the extra weight of two knives so as to have a utility tool and one that was designed for fighting, my reasoning being that I would not want to have to fight with a short thick utility knife that isn't well suited to the job and I would not want to use a dedicated combat knife that might not hold up to the task and a trade off wouldn't be particularly useful for either. I'm not educated in these matters though, I will put up a few designs that I came up with to see what changes you would do to them.
 
Don't get me wrong, I'm an Infantry soldier and I love big knives. The problem is that I have found that I never really need one. Granted, a larger knife is easier to use for cutting brush if you are building a hide site but I have successfully used a 3.5-4" blade to do the task. The key is to have a blade that has the right geometry for cutting and is easily resharpened but also has a comfortable handle for hard use. As for hammering, you can typically find a BFR ( big freakin rock) to use if you need to hammer something. Also keep in mind that smaller knives are easier carried and can be mounted just about anywhere without being cumbersome or getting in your way.

A few years ago I received an amazing gift from Mr. Bill Coye, one of his Ridge Back models. It immediately became my daily carry knife and I used it for EVERYTHING. Using the R.B. proved to me that bigger isn't always better. In fact, I loved the R.B. so much that I used the principle to design my next daily carry. The fixed blade I carry in the field now has an OAL of just 6.5" divided equally between blade and handle. The blade is almost 1.5" wide, 5/32" thick, distally tapered, spear point design made of 1095 and has a tapered tang and micarta scales with corby fasteners and kydex sheath. I can mount it anywhere without it getting in the way, but yet it is always convenient to grab and so light weight that I forget that I have it til I need it.

I also have a larger blade that I carry on my pack in the event I need something larger for heavy tasks. It's a copy of Jim Crowell's Arkansas Park Ranger Knife which Jim made for me. It has a 5" distally tapered, drop point blade made of 1/4" CPM 154 CM of narrow tang construction with a stainless guard and micarta handle. I rarely find need to use it, but it is always in my pack if needed.

Please keep in mind that these are just my personal preferences. Each soldier is different as night and day when it comes to what they want to carry and use. The key is comfort of grip and blade design which is geometrically correct for hard use regardless of size. I would recommend sticking with proven blade shapes (ie. clip point, drop point, spear point) as they are easier to sharpen. I would also recommend using a phenolic handle material (micarta or G-10) as they are impervious to climate and weather conditions.
 
My addition to this chat about the ultimate knife for a soldier brings me to say that

First, I didn't serve in the US military or any other, but I have made field knives for US soldiers past and present

The handle is the most important part of the knife as far as I am concerned because if it's not comfortable a soldier or anyone else won't use it but once and then take something else on the next Mission/deployment.

I design from the handle to the blade so the customer/Soldier is comfortable and happy with the knife. I have them trace out their dominant hand on a piece of paper so I have a reference to work by when shaping the scales.

As Mr. Murph as stated they are used as tools mostly.
The vet & active service folks "For Various conflicts/Wars" I have built knives for have mentioned in no particular order.
Digging a hole to get out of the shrapnel bursts or for tent spikes, Cutting rope to use to restrain someone, Breaching a door, Digging a hole to relieve oneself in, opening ammo crates, Cans, C-ration or other food stuff containers, shaving wood to start a fire. This goes back to men and some women who served in WWII and every other lousy place they have ended up since.

I have spoken with one service vet that used his knife in combat in WWII in the Philippines. he used his knife to dispatch a Japanese sentry on a raid to keep things quiet. I know that knives have been used in more recent combat but all I have spoken with have relied on our overwhelming firepower that our soldiers usually have.

The blades I have made for service people have been 6-7" tops, usually 5-6" , 1 1/3" or less in height and 3/16" or less in thickness usually 1/4" or less.

Clip or drop point thick at the tip for some prying while still a distal taper which gives you a stronger blade and plain edge razor sharp.

The Rambo type movies give us a different image of the war most soldier fight. there are a few special forces elite soldiers or those in a tuff spot that may rely on the quietness of a knife for combat but most by far use it as a handy tool to get a mundane task done.

Laurence

www.rhinoknives.com
 
I fully understand what you're saying Murph. I'm retired infantry and a Vietnam vet. I always carried a fixed blade knife, but it spent more time opening C ration boxes and doing other chores. I used a folder more. Besides, if I have to use a knife in combat I don't want to play.
 
I have designed what I think is a half decent combat knife, I shall upload the pictures tomorrow. I did it in 3 different sizes, I think it was a 4 1/2", 5" and 6" blade to the nearest 1/2". The big one is because I don't have my own knife and I want one that can be used for light chopping. Once I get the patterns up you guys can tell me what you think, input is always good. I have a design for some sheaths also, kydex with a 304ss welt (I'm not sure about weight, might go with aluminium if it comes out too heavy. See what you think, tell me what to change. I will get up early and post pictures as I said.
 
What is the thought process on the stainless welt on the sheath?

Looking forward to seeing your designs.
 
Thought process is that kydex is a thermoplastic and right now wars are being fought in hot places, the welt serves the same purpose as with leather by protecting the rest of the sheath but also by preventing flexing that could result in the edge touching a soft part of the sheath and damaging it. I was thinking straight to aluminium though, the mother made me revise chemistry and I remembered that alluminium would protect the blade from rust and also won't do as much damage to the edge.
 
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http://imageshack.us/a/img546/9711/photoapr03123814.jpg
The sizes were completely wrong. I might make a smaller one still. I figured that a soldier would want a stronger point over a belly so it is a tanto. The fancy choils don't mean much but I tried to incorporate a bottle opener into the middle one. I have been trying to design a locking mechanism for the sheaths also but that might not happen. I measured the blades, 5 1/2", 6" and 7" is what they are. I also want to know what accessories would be good to come with the sheath. A pocket with a sharpening stone? A pouch with a survival kit? That kind of stuff.
 
They look good overall. I think I would dispense with the bottle opener (how much other gear already has a bottle opener on it? I know my Leatherman does, as well as cheap Swiss Army types). The choil/guard area on the long one looks best, the guard on the shortest one is fairly pointy.

Is there a purpose to the step on the spine on the longer two? If not, I think I'd go with the spine style on the shortest one.

All in all, look like straightforward workable designs.
 
The bottle opener is already amputated, overcomplicated and unnecessarry. The step is a thumb rise, I will make one without it. I will get a sketch of the sheath concept up as well.
 
LiamLynch said:
http://imageshack.us/a/img546/9711/photoapr03123814.jpg
The sizes were completely wrong. I might make a smaller one still. I figured that a soldier would want a stronger point over a belly so it is a tanto. The fancy choils don't mean much but I tried to incorporate a bottle opener into the middle one. I have been trying to design a locking mechanism for the sheaths also but that might not happen. I measured the blades, 5 1/2", 6" and 7" is what they are. I also want to know what accessories would be good to come with the sheath. A pocket with a sharpening stone? A pouch with a survival kit? That kind of stuff.
Click to expand...

Liam,
A belly type blade can be just as strong as a Tanto. It all depends on the geometry of the grind and the thickness. A bellied blade works better in a slashing stroke, maybe a little better in a stabbing trust but that may not be 100%?

I personally think the Americanized Tanto tip is overrated. You know that this tip did not exist on Knife sized weapons in Japan until about 20-30 years ago.

Laurence

www.rhinoknives.com
 
I have no idea how to design a strong geometry. All I do is roughly work out an angle that looks strong and make the grind height roughly where that angle would happen if that makes sense. The westernised tanto is easier to make strong as the point will naturally be a larger angle. I thought about slashing but if you are defending yourself with a knife stabbing them is probably the way forward. Maybe a kind of halfway tanto is best? A very obtuse secondary point so it is close to a single bevel but still has the tanto point, effectively a tanto where both edges amlmost curve into each other? More pictures required.
 
Ok, I can see it as a thumb ramp. Makes good sense now.

Westernized tantos have kind of come to be associated with military knives for whatever reason (strength or marketing?), but I think some belly is more generally useful and can be made at a similar angle. Try this, if you feel like it: Make a copy of your tip design, then choose a point just back of and another just ahead of your yokote line. Now, connect those points with a smooth curve and get rid of the yokote so you have one long bevel. Your tip is essentially unchanged, but now you have a belly on your blade instead of a tanto tip. See what you think of the look.
 
Got the sheath sketched, I'll upload pictures in a minute. (Or however long it takes me to type with this evil virtual keyboard.)
 
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