KA-BAR TDI Knife Review: Unsafe for Duty

When I arrived at work yesterday, there was some buzz about a training incident between an FTO and a recruit that had occurred earlier in the day.  It seems that it was our new recruits’ first day in the blue uniform.  Some of them were assigned to Daywatch.  After roll call, they were examined by their training officers.

One of the FTO’s noticed a strange handle sticking out of the front of the recruit’s gun belt.  Yes, it was a KA-BAR TDI knife, ostensibly designed for an officer’s last ditch self defense.

The FTO had never actually handled a TDI, but he had heard of them.  To demonstrate the vulnerability of the knife, the FTO reached out just to tug on the handle of the TDI.  To his surprise, the blade came right out!  The recruit instinctively went to grab his knife and bang!  He got cut.  Oh, dear.

I purchased a KA-BAR TDI two years ago.  I threaded it into my underbelt and situated it in the recommended location, behind my gun belt’s double magazine pouch on my support side front.  Tactical Defense Institute said the knife could be mounted in either a forward or reverse grip for the support hand.  I have trained in a reverse grip.  In either position, I was immediately concerned with its lack of security.  It did not stay there the whole shift.  A fellow sergeant also had the same experience.

The problem is not with the knife itself.  The TDI positions the blade aggressively in the hand for cutting and punching with a straight wrist.  Its handle is relieved to lock the index finger and prevent one’s digits from sliding on to the blade.  With training, the TDI can be wielded with great martial lethality.

Ultimately, I find the sheath of this knife to be its Achilles’ heel.  The molded polymer sheath has no retention, save a friction fit.  For a knife that is going to be carried out in the open, it should have a locking device similar to a Level II retention gun holster.

On 12/24/2010, Austin, TX Police Ofc. Frank Wilson found out the shortcomings of a KA-BAR TDI, firsthand.  During a physical struggle, suspect Maurice Pierce was able to pull Ofc. Wilson’s TDI from its sheath and slash Wilson across the neck.  Seriously injured, Wilson transitioned to his firearm and shot Pierce, who was killed.  Ofc. Wilson recovered from his wounds.  Austin PD banned any knife not carried in an enclosed case or secreted on the officer’s person.

The KA-BAR TDI was designed by Tactical Defense Institute (TDI) President and Chief Instructor John Benner.  Benner is an Army veteran and a police officer with over thirty-seven years of service.  The intent of the TDI knife, as a back-up blade for law enforcement, is admirable.

As I said, I like the actual knife, but I strongly feel the sheath and its intended carry placement of the TDI are unsafe for duty.  It would increase the price of the TDI to re-engineer the sheath to give it a retention quality, but that would minimize the platform as a danger to the user.  If you have a co-worker carrying a TDI, please pass along this info.


Update 3/22/2014:  KA-BAR has new TDI’s out with a locking sheath.  Read here:  New KA-BAR TDI Hinderance and Hell Fire Knives.  Problem solved!

Another Update 1/31/2015:  I got to examine the new TDI knives and sheaths at 2015 SHOT Show.  Click here.


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33 Responses to KA-BAR TDI Knife Review: Unsafe for Duty

  1. M@ says:

    Most of the guys I work with carry these, I’ll definitely pass this along.

    I’ve found that some TDI sheaths fit tighter than others. I have one of each, and have found that even the same knife can fit differently in another’s sheath.

    I have researched after market kydex sheaths, and have a couple to look decent, but have not handled them in person. We’re kicking around the idea of making one too.

  2. M@ says:

    Also, are the pics not loading for anybody else?

  3. Dan says:

    I mounted mine to my vest under my shirt for the very same reason. I also dont wear pens in my shirt pocket as those are also weapons of opportunity for an adversary.

  4. Randall says:

    M@, the first photo had a pretty high res, so I toned it down.

    Dan, before we had a secondary firearm policy, one our guys carried a TDI on his vest straps…


  5. ariel says:

    The article title, “Ka-Bar TDI Knife Review; Unsafe for Duty,” is misleading.

    It suggests there is something wrong with the knife itself, when in fact, the shortcoming is with the factory sheath.

    The article could just as well be titled, “Glock 19 Review; Unsafe for Duty,” because the factory Glock holsters suck. Of course you want to use a retention holster for your exposed duty gun. That goes without saying. Same thing goes for an exposed knife.

    Most serious knife people will have a custom sheath made. Heck, most really high end knives don’t even come with a sheath due to this fact.

    The answer is simple – have a custom retention sheath made, or conceal the knife.

    • Randall says:

      I obviously don’t consider it misleading. Since the TDI comes as a package with knife and sheath combination, and is squarely marketed to be worn together on duty for law enforcement, I think my evaluation is fair. I agree that a custom sheath is in order. That said, if the knife came with a disclaimer that the sheath is not fit for street duty, I could be more sympathetic.


  6. Jayrob5025 says:

    I’ve like the idea of the TDI knife since it originally came out. Like most everyone else I was very concerned with the weapon retention. My solution to TDI carry was to velcro the sheath inside of a Un#le M*kes pocket holster and carry the knife in my non-dominant side pants pocket. The knife is concealed but is accessible.

  7. GhostTac says:

    Im not a LEO (yet) but most of my friends are and they all carry the TDI’s. Some carry them on thier duty belts behind their double mag holders with their shirt tucked over the handle so its not visible. Another option is if you use an external vest that you can rig it so that the sheath sits just under the vest but far enough up that the handle can not be seen. Also have a buddy who wears his on the inside of his vest but on the side (also on an external carrier).

  8. 405 says:

    Simply place directly underneath the Taser. Hides well and accessible with both hands. Then be a kick and a half distance away from your opponent for reactionary gap.

  9. Matt says:

    Randall, excellent article. I came across your site by accident and have been bombing around on it for a bit. I couldn’t agree with you more about the the Kabar TDI as far as you assessment on functionality and usability. I also agree that the stock sheaths that come with the knife are repulsive. I am from Lakeland, FL, so I may not be too far from you. I own a custom shop that specializes in kydex gear, and I make a sheath for the TDI.

  10. Doc says:

    I love this knife and still trust it as a last ditch weapon. I carried this knife back sometime prior to 2009 when I was in plain clothes. When I purchased it, it came with an ankle holster- in case I was ever pinned on my strong side-, not the holster shown above. I never had a problem with it coming out of its holster. However, the holster above seems to be counter intuitive; knives are meant to be felt and not seen. Ive now done the opposite transition of many officers. After almost a decade in LE I joined the Army. I am currently in Iraq and still have this knife with me, but unlike many of my grunts its not largely displayed for all to see like many of the “private swords” I see here.

  11. JRT6 says:

    “Cop has glock taken from his holster and used against him so tell all your co-workers carrying their guns on their duty belt to be fore warned that glocks (insert gun here) are unsafe for duty”.

    Ok got it.

    • Randall says:

      Golly, JRT6, your logic is infallible. Oh, wait, police officers carry handguns in Level II and III retention holsters, but an out-of-the-box TDI knife has no safety to its sheath. Soooo, the TDI is unsafe, but an officer’s holster is made to retain its weapon. JRT6 + Sarcasm = Fail. But thanks for stopping by.


      • 76one says:

        It’s noteworthy that some officers carry their guns in a certain brand of holster that has proven itself to fail and separate from the duty belt regardless of retention level, but they remain issued/authorized items. I think JRT6’s comment certainly has merit in that regard.

  12. Acheron says:

    so buy a decent sheath (most stock sheaths are garbage anyway) and conceal the damn thing.

  13. Weasel says:

    Just wondering how you guys are concealing your tdi and is it still easy to access? Keeping in mind that when you need it you will be in a close hand to hand fight for your life.

  14. JRT6 says:

    I wear an outer vest carrier so I wear the large tanto on my belt and hide the handle under my vest. Not a quick draw for me but not for a BG either if lock up in some kind of hand to hand.

    I work with a regional group of law enforcement trainers that proved free training for LE at the Alliance Police Training range (the range featured in Tom Clancy’s Rainbow Six Siege trailer) and we get some of the regions best tool makers in and out so getting a sheath made for what I need is convenient and inexpensive. I just had a TDI trainer made for $20- by a guy from Ill if anyone is interested shoot me an email.

  15. JRT6 says:

    I missed your follow-up with the Hinderance which is on me because you’re offering a (good) solution to your complaint.

    However I still disagree with your rationale and titling your article “KA-BAR TDI Knife Review: Unsafe for Duty” was misleading and hyperbole.

  16. Seth says:

    Randall is correct. As packaged the TDI is unsafe for duty use. As an officer and Krav Maga practitioner I test all products before I carry them into the field. With basic grappling or an serious jostle, the TDI popped out of its stock sheath 8/10 times. This testing included takedowns, stand up, grappling, hurdling, running, and walls. With that being said, the knife is amazing for duty use with a proper sheath. I ordered mine from phlster.com and the retention on their sheath requires a deliberate pull to release the knife. I performed all the same tests and never once did the knife come unsheathed, this included a deliberate grab my “attacker”. The draw has to be a sharp yank upwards, it won’t come out being pulled away.

    As for placement of the TDI, I attach it attached to my inner belt and it sits right behind my mag carrier. Even with an outer carrier I am able to get to it with my right or left hand.

    • Seth says:

      Forgive the grammar errors. I’m replying via phn and the auto correct is horrendous and the reply method for the site also messes with the phone.

      I meant hurdling, not hurtling, and I also didn’t mean to put the two attached phrases in the same sentence.

  17. JRT6 says:

    While I don’t consider the sheaths garbage they certainly are the weak point of the product and I’ve had to replace one on the two TDI’s I have.

    As several people have pointed out if you buy gun to review and that gun comes with a cheap shit holster for marketing purposes or what ever do you claim that gun is not fit for duty? No you base your review on the gun after throwing the holster out and buying a good one. That’s why I was sarcastic because the logic presented is maddening. The title of the article comes off as click bait and it tends to illicit a similar response.

    • Randall says:

      “While I don’t consider the sheaths garbage they certainly are the weak point of the product and I’ve had to replace one on the two TDI’s I have.” Yeah, unsafe for duty.


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  19. Jeff Nelson says:

    I agree with the issues with the sheath that comes with the TDI and its lack of retention. There are good after market sheaths. The phlster fightworthy sheath has much better retention .

  20. JRT6 says:

    A knife maker friend of mine made me a new sheath with a nub on it that really holds the knife in tight.

  21. JRT6 says:

    A knife maker friend of mine made me a new sheath with a nub on it that really holds the knife in tight. I carry the big tanto.

  22. Joshua says:

    Do you know of anyone who sells a good retention sheath for this? I’ve been looking online but can’t seem to find anything…

  23. jaxskb says:

    They make one with a retention sheath. I purchased mine from amazon. See link below.
    KA-BAR TDI Hinderance Fixed Blade Tactical Self Defense Knife https://www.amazon.com/dp/B00ILFN9AO/ref=cm_sw_r_cp_apa_PBVQzb6MTPXYK

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