TTAK Knife Testing Protocol: Cardboard Block Penetration

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I tested 5 knives and a tactical pen, measuring penetration into stacked cardboard.

I have been looking for new ways to test knives, subjecting them to realistic and objective challenges. I don’t have the budget to make ballistic gel torsos to destroy, but cardboard is mostly free and offers standardized means of measure. I came up with this test when brainstorming ways to test Will Woods’ Kraken. And naturally, I decided to try a few more knives for comparison as well as a Range Master tactical pen.

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Micarta scales and the developed sub-hilt give the operator a rock solid grip, even through the sudden stop at peak penetration.

I already reported that I achieved about 2 1/4″ of cardboard penetration with my Range Master Tactical Pen. This would be my baseline against which to judge the knives.

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The Kraken penetrated between 3-3 1/4″ of cardboard per attempt.

The Kraken led off the test. All three attempts broke 3″, with the greatest penetration being 3 1/4″. The micarta scales provided firm grip throughout.

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My Kim Breed Model 15 provided results similar to the Kraken.

Wrapping up the fixed blades, I decided to give the Mora Bushcraft a whirl. Nothing about the Mora surprises me anymore so when the first strike almost reached the hilt, I was more surprised that the following two did not.

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The Mora Bushcraft: Is there anything it can’t do?

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Middle strike measures 3.5″. The first topped out at just shy of 4″.

Just for edification’s sake, I decided to throw two folders into the mix. The first is the Cold Steel Mackinac Hunter – a folder that is more robust than many fixed-blade knives. The second was the Benchmade Mini-Griptillian, my most frequent EDC blade.

The Cold Steel Mackinac Hunter had penetration results similar to the fixed blades I tested. The Mackinac ranged from 2.75″-3.4″.

Finally, the little Mini-Grip punched over its weight. It buried itself to the thumb stud on all 3 strikes. Apparently, a razor sharp skinny blade is better suited to piercing cardboard than even the sharpest big knife.

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The extremely sharp and thin blade of the Benchmade Mini-Griptilian maxed itself out on all three strikes.

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All 3 strikes maxed out at 2.5″


Putting the whole test in perspective, the performance of the tactical pen is even more impressive. It isn’t a knife, but provides considerable penetration power for times when a knife is not available.

I am not willing to call my rudimentary test as the final word on anything. But it seems as if thinner blades and uniform shape (the Mora’s parallel blade cheeks verses the wedge of the Breed and Woods knives) travel a bit farther before running out of steam.

It seems as if 3.5″ is a good working benchmark for blade performance. For those blades big enough, it was the high water mark for several. I will be replicating this test in future knife reviews, so those that reach this point will have a mark of distinction.

I will have full reviews of the Breed and the Kraken as testing wraps up. But there is still lots to do. The Kraken is proving itself fairly adept as a kitchen implement, making prep-work easy for this weekend’s chicken curry.

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The Kraken is demonstrating substantial culinary chops as well.


  1. Sam L. says:

    Do you run your cardboard pieces with the ribs parallel or alternating perpendicular? I have a Mini-Grip (1/2 serrated). I don’t see it as a thin blade; seems to me pretty thick for its size.

    1. The ribs were fairly randomly dispersed. I was trying to make a tight stack, so whichever way fit best is how it went together.

      As for the Mini-Grip. I agree that it is nicely robust in the blade, but compared to the other knives tested, it was downright delicate.

  2. Mark says:

    The way to standardize this test would be to alternate the layers of cardboard so that the ribbing runs both directions. That way the direction of the blade won’t matter much. The cardboard stack need not be quite so long or wide. It only needs to be 3″ thick. A stack of cardboard squares about 6″ x 6″ stacked 20 layers deep would probably suffice. Then you would need to apply a standard pressure. Otherwise the weight of the knife and its handle will affect your results. The knife should be clamped into a vise with foam padding around the grip – foam pipe insulation might work – with its tip pointing straight up. Then the thick cardboard stack should be gently placed on the tip with a specified weight on top of it. The test could be to determine how much weight is needed to penetrate 3″ of cardboard.

  3. Tom in Oregon says:

    At the SOF 3 gun match in about 1990, a well known knife manufacturer had a demo going, demonstrating their new rubbery grip. (Kraton?).
    They were stabbing tires with fixed blade knives after dipping the handles in oil.
    They asked for a volunteer from the audience. Yep. His hand slid right down the blade. 12 hours of micro surgery later… He showed up to the shoot the next day in a full arm cast. Rods and wires poking out of his hand.

    Be careful, Sir.

  4. I_Like_Pie says:

    I know that it sounds odd and counterintuitive, but I haven’t found that knives like these are the best tools for stabbing motions. The risk is way too great if your fingers slip over the blade. A-OK if you are pushing the point slowly and controlled into something line a melon, piece of meat, etc. The quick stab makes me cringe when I see it just because of the damage done to the hand if it goes south.

    They can be used for such actions if needed, but chisels, punches and scrapers for me are the best tool for the task.

    …not meaning to take away from the valid test above. Other people may have a different take on the use of such knives.

    1. I understand your concern. If you look at the photos, I have my thumb firmly curled around the pommel of each knife. Not a perfect solution, but I feel fairly confident or I wouldn’t do it.

      1. I_Like_Pie says:

        That being said….Kraken FTW!

      2. Chuck W says:

        I have saw on many police shows like Dateline and on ID Discovery channel and the cops do talk alot about how they catch knife attack killers alot because after 1 or 2 stabs the knife gets slippery and the person’s hand will slide down the blade. If you are fighting for your life then heck I’ll put up with some stitches to keep an attacker away. I did buy a knife at Walmart I think a Winchester it actually had a hole your pointing finger went into to keep you from possibly doing that. It seamed like a good idea but after I purchased it and used it a few times it wax very uncomfortable knife to use. I like you Benchmade knife and can see why it would go deeper. I have a Zero Tolerance 301ST with green handle and zebra striped blade. It’s very nice knife bug it’s got a thickER blade on it which I would think would stop quicker than a slimmer blade. That being said it won’t break as easily as a thinner blade would or it shouldn’t. I quit carrying it cause of weight plus they actually discontinued that color scheme and the guy at SMKW said he wants to buy it so he can put it up like it’s going to go up in price. I wish it would but I don’t think I’m that lucky. Lol. Nice article I found it very interesting

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TTAK Knife Testing Protocol: Cardboard Block Penetration

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