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New EDC Knife: Ka-Bar TDI

Discussion in 'Non-Firearm Weapons' started by AdamSean, Jan 29, 2013.

  1. AdamSean

    AdamSean Well-Known Member

    I have carried a knife for defense everyday for as long as I can remember. It usually a folding knife clipped in my pocket. But I have been eyeing a nifty looking fixed blade for a couple of years. Why I took so long to get one, I have no clue. I ordered it Friday and it arrived today. Its a Ka-Bar TDI large plain edge. It has a bend in the middle to give it a pistol like grip. It was actually designed with police and other law enforcement in mind. It is supposed to be worn on the off side from the firearm in the case an officer finds himself in a situation where someone is trying to take his gun. He can then grab the TDI from its kydex sheath and defend himself. The knife can also be effectively used with an underhand grip. It came with 2 straps that can be used with a Molle strap system. I also ordered a clip that attaches and can be worn IWB. This is my intended use. I was looking at some videos about this knife and came across a demo by TDI instructors. They set up a balloon and asked volunteers to pull out a folding knife and pop the balloon with the use of a timer. The average time it took was 2.5 seconds. Then they were asked to use the TDI knife. Average time was .75 seconds. It was a really cool video. All I need now is some type of trainer to practice this uniquely shaped knife.




  2. rjrivero

    rjrivero Well-Known Member

    Kabar actually makes a trainer for this as well. Their class is very well done if you ever have a chance to go there and take it. The TDI instructor cadre are a bunch of good guys. (All the ones I know anyway.)

  3. conw

    conw Well-Known Member

    It's a great knife for its intended purpose. I haven't seen the factory sheath but one thing people I know have done is buy a good custom kydex sheath to improve access and facilitate concealment.

    NB: I would strongly advise utilizing your thumb to wrap around while gripping.
  4. AdamSean

    AdamSean Well-Known Member

    I have trained with knives for 10 years. There are a multitude of grips and we were taught to keep the thumb along the spine for wrist stability. Generally, people look confused when I take a fighting stance. But when we engage, they never stand a chance. I learned through Shen Lung Kung Fu. Learning to adapt and not sticking to one exact technique is how I was taught. I plan on learning the best way to use this knife. I truly like the design. I have discovered that I can draw it fastest with the underhand grip so I really need to learn how it will work best in that case. I keep getting my arms in bad positions and crossing my center line, which is a no no in Kung Fu. I might be better off practicing drawing with the overhand grip. I can keep my movements more natural and get better cuts. Time and practice will tell which will be better.
  5. Bobson

    Bobson Well-Known Member

    I've handled the knife and sheath at my local Sportsman's Warehouse. The included kydex sheath appears very well made. It holds the knife securely and it is extremely concealable when worn on the belt, even under nothing more than a generic white t-shirt.

    Hope you enjoy the knife and never need to use it, OP. I gave it serious consideration, myself, after seeing the balloon demo video you mentioned. For ~35 bucks, you can't go wrong with it.
  6. earlthegoat2

    earlthegoat2 Well-Known Member

    I picked one up after reading The Snubby Revolver by Ed Lovette. He gives high praise for it.

    I unfortunately could not figure out a decent carry method for it and gifted it to a police officer friend of mine. He absolutely loves it and he carries it as part of his duty gear regularly.
  7. conw

    conw Well-Known Member

    Bobson, cool; I had seen pics but figured people wanted custom Kydex for a reason... no idea but glad to hear it seems to work really well. I think OWB under a cover garment is the ideal carry method for this kind of knife. Ahh, I think I know... the factory sheath is more designed for IWB it would appear.

    Adam, don't take this disagreement the wrong way, but I don't think you are correct. I'm sharing this in the spirit of discussion, nothing personal.

    First of all I think the underlying assumption that more positions/stances/moves are better is not necessarily correct. It's like alternating between EDC of a revolver and a semi-auto because you can: a solution looking for a problem. Further some of the techniques are likely to not work as well as others.

    The idea that you will react quickly, diagnose the situation, and select from a catalog of many possible techniques (multiple concepts of how to stand, how to hold a knife, etc) also would seem to be overly optimistic, particularly when you have Hick's law (more decisions = more time needed to decide) and in all likelihood could be better at one or two high percentage methods (such as ice pick forward and reverse grip for example) and spend more of your limited training time getting *really* good at them.

    That may be a bit unfair to you; I don't know you or your skills or really anything else, but I do stand by what I said; it may not apply to you though, and that's fine too.

    Now, as far as specific grips and hand positions.

    Practice forward and reverse... one of the great thing about that knife is that it allows really effective, powerful striking in either position, and the angle of the handle facilitates a locked wrist position. I think the knife is best positioned somewhere either hand can access it and then practice both types of draws.

    I am very, very skeptical that a thumb braced against the back of the knife increases wrist stability. Even if it did I think it makes an unacceptable trade-off: your retention of the knife is palpably reduced.

    Generally the argument in favor of the "sabre grip" you are using is that it enables more precision cuts or stabs, and that's fine: it does. But it also reduces the ability to retain the knife when unexpected force torques it against your grip.

    I have never seen a training scenario where someone was totally unable to stab someone else with a small training knife for lack of accuracy, nor have I seen a scenario where someone's wrist failed and rendered their lower arm a limp noodle. But I have seen many people drop their knives or fumble the drawstroke or lose just enough grip that they begin adjusting their grips mid-fight.

    Biomechanics studies seem to be with me on this. There are generally two types of grips, power grasps and precision grasps. There is an inherent tradeoff: more power = less precision. The thumb may be used to increase grasp strength (power grasp) or stabilize and facilitate precision.

    According to Wikipedia citing Gray's Anatomy, when the thumb is fixed, the same muscle in the forearm also contributes to wrist flexion. If a concern is wrist stability, it would appear that securing the thumb in a fixed position would be important; I think the power grasp ensures this best, specifically wrapping the thumb around an object.

    According to this article on Cornell's site what you are using is called the "hook grip":

    Hook grasp - characterized by a flat hand, curled fingers, and thumb used passively to stabilize the load, e.g. auto steering wheels. Load is supported by fingers. This grip is most effective when the arms are down at the side of the body. For objects with a diameter of 2" the hook grip strength can achieve the strength of a power grip. Very narrow handles decreases hook grip strength by pressing deeply into hand and fingers. Rigid handles should generally be avoided.​

    Bottom line: I think the icepick grip or a power grasp with thumb-cap make better use of the muscles in the hand and lower arm, and would urge you to experiment on your own, with your new knife, rather than go solely off of someone's word. But you should also consider evidence over anecdote.
  8. CBPAdam

    CBPAdam New Member

    I carry one on duty, and love it. Very handy to get at, comfortable to use, sharpens up real nice, too. I've tried carryingit a couple of different ways off-duty, and just can't find a way I like without feeling like a still have my duty gear on. I did come across a folding version that is supposed to be nearly the same size, so I'm going to give it a try.
  9. AdamSean

    AdamSean Well-Known Member

    To each his own on how to use and grip a certain knife. Somethings work better for others than someone else. People stand there and scratch their heads looking at the grip we use on a bo staff. But put into action they understand. And then some just don't like it because it feels so awkward. Sifu teaches one way, but leaves it to the individual to adapt and form the best way for them to perform a technique. For instance, I cannot make a full fist due to serious tendon damage. But I can use the outside edges of my hands and forarms to strike well.

    I don't take this at all as an arguement. I understand your points. The main reason we hold the knife along the spine is because we learned how to strike the side of the blade in such a way it will dislocate the thumb if it is wrapped around the grip. It is something I learned firsthand. Another thing we learned was to never be afraid of letting go of a weapon if it is called for and gives you an advantage.

    I look at as I look at the different martial arts. Some people prefer boxing, some Tae Kwon Do, and others Kung Fu. Some are just better for some. It works for me and that is what matters. It has saved my life once, if I need to use it again, I'm sure it will do the same as the first.
  10. lobo9er

    lobo9er Well-Known Member

    I hate to make this about the grip in the picture. just wondering if you can explain or if there is a vid on youtube of how you would strike and dislocate your thumb?

    And congrats on the knife!
  11. Gordon

    Gordon Well-Known Member

    I got both my pretty high school grand daughters TDI's and trained them in how to use one when grappling :evil:
  12. AdamSean

    AdamSean Well-Known Member

    I cannot demonstrate anything I have been taught to anyone outside of Shen Lung Kung Fu. It is a promise me make when taught such potentially dangerous techniques. I have only taught 2 outsiders knife fighting, but only with the permission of my Sifu.
  13. Ehtereon11B

    Ehtereon11B internet infantryman

    I have had a TDI large knife for about 7 years and it is one of my favorite ones in my collection for carry.
  14. Loc n Load

    Loc n Load Well-Known Member


    TDI's are great knifes, I know a lot of brother officers who carry them. They can be carried on duty belts, or on tac gear if we are "dressed for success".
    I have had a lot of CQB trng over a period of 4 decades, and one of the most important things I have learned is that in order to implement a weapon, first you have to have one. And I have seen the aftermath of a lot of real world "knife fights". Usually only one person knew they were in a knife fight and that was the one doing the cutting.
  15. lobo9er

    lobo9er Well-Known Member

    I don't want to be disrespectful but can anyone hint at how to dislocate my thumb while I use a knife? I have been screwing around with knives trying to find a useful method that would put my thumb in jeopardy only thing I got is if I were to "flick it" at a target to the side. I'm not sure how effective that would be though.
  16. Tirod

    Tirod Well-Known Member

    The balloon test is a bit bogus. After all, a fixed is 100% open as soon as it clears the sheath. The folder remains to be opened, and AO or switchblade wouldn't make up the difference. It's not a special advantage of the TDI, any fixed in a practiced hand can pop a balloon faster.

    However, it brings up whether speed of presentation has a tactical advantage. As said, one person knows they are in a knife fight, which calls into question why the other completely missed all the sociological and tactical cues that other person intended serious bodily harm. Why are they grappling over the officers holstered weapon? It invites a lot more analysis.

    These oft quoted situations seem to pop up when marketing a "solution," be careful what you are paying for.
  17. conw

    conw Well-Known Member

    I sort of agree that "speed" is a less important quality in presentation of knives than, say, in handguns.

    But in comparing a fixed blade to a folder in training scenarios, for similar reasons that raw speed is not that important - the fight is usually entangled when a knife comes into play - a properly designed fixed blade (good handle for retention, angled properly) is much, much more reliable to bring into the fight because there are fewer steps involved, which is the root cause of why it's faster, but a more important aspect than the speed itself.

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