Zero Tolerance 0640, by Pat Cascio

To those many readers who have requested, once again, some high-end folding knives, here’s one that is quite unique. Its not all that easy getting our hands on high-end folding knives because, well…they are very expensive and always in-demand. Today we’re taking a close look at the Zero Tolerance Model 0640 and it’s a winner in every respect.

As I’ve said numerous times, you can buy a knife for $5, or one for several hundred dollars, but don’t expect the less expensive knife to stand up like a quality knife. There are some really nice knives on the market, that are sold on some of those knife selling infomercial channels, where you can get dozens of knives for a hundred bucks, and they look good – in the commercials. However once you get them in your hands, they are nothing more than eye candy. They look good, but they have blades that aren’t heat treated, and most come dull, too. Oh sure, you’ve watched those snake oil salesmen demonstrate how sharp those knives are, by slicing a piece of paper. Well, they took those blades and put an edge on them so that they will do that. Just don’t expect those eye candy blades to do that more than a few times – it ain’t gonna happen.

I really like the Swiss Army knife concept, if only they made they with the best materials. However, if you try using any of those numerous tools that comes on these days, and apply any amount of force, you’ll soon find that you are holding that knife in pieces in your hand – they just aren’t up to the super hard tasks like the high quality multi-tools that we have today. Again, great idea, all those tools in a knife, but I wouldn’t want to bet my life on them.

So, just because a knife looks great on television, don’t expect something that costs a buck or two, to stand up to the rigors of survival, law enforcement, or military duties. You are throwing your money away, and maybe even your life, if you purchase garbage cutlery. Now, with that said, you can get some really high-quality knives from some big name knife companies, like Kershaw Knives, which is a division of Kai USA Corporation, which also owns Zero Tolerance knives. I’ve tested some Kershaw Knives that retailed for $40 to $50 and I’ve got to tell you, they are well-made – quality – for your money. Sure, some are made overseas, but made under strict quality control, and they are not made in slave labor factories.

The Zero Tolerance line of knives are designed for hard-use. I’ve also mentioned this before – many times before – the ZT line of knives are near custom quality or exceed many custom made knives in quality and design. I used to collect custom made knives – some of my own design, and many of those knives exceeded $500 to $700 in price. However they were not as well made as the ZT line of knives. Modern manufacturing techniques have allowed this to be, as well, as highly trained technicians assembling and fitting these knives – and lets not forget the top-notch materials use to produce these knives. Today’s stainless steel blades are some of the best to ever come along – they take a great edge and will hold it for a good long time, and they are also easy to re-sharpen. I once went ‘round and ‘round with one of my editors about this subject when I stated some of today’s super stainless steels hold an edge and are easy to re-sharpen – he told me it was impossible for a blade steel to do both – he was wrong then, and he’d be wrong now.

At one time, handle materials like G10 were the exclusive domain or custom knife makers and it was expensive to put on a knife handle. Not so today – while it isn’t a cheap material, it has come down in price, because so many factories are producing knives with handle made out of G-10. Today many folding knives can be found with handles made out of carbon fiber and not just in black, either.

An Emerson Design

Ernest Emerson, a long time friend and custom knife maker/designer, joined forces with Zero Tolerance and Kershaw, to have them produce some of his designs. Many times, if you look at Emerson’s web site, you will still see that he is out-of-stock on many of his own knives that are produced in his own factory. While that’s good, its also bad news, for those of us who want one of his knives. It’s also bad news because many of us cannot afford genuine Emerson knives from his factory. So, his collaborations with ZT and Kershaw are a good thing for many of us.

Emerson’s 0640 is one of his newest collaborations with ZT Knives, and this one is a winner in all respects. The 0604 is a nice-sized folder, that has a 3.75-inch blade – and that is just about perfect for my own uses – seems like this blade just balances perfectly for me and it’s not too big, nor too small to carry all day long in your pocket, with its ambidextrous pocket clip. The blade is made out of one of the newest super stainless steels, too – CPM 20CV and this stuff will hold an edge a very long time, as well as being fairly easy to re-sharpen, too.

The handle on the 0640 is made out of Titanium and this is this stuff is strong. light, and expensive. The handle scales are made out of a green/black Carbon Fiber – and if you hold it under a light for a few minutes, it glows a spooky greenish color, very cool looking to say the least. There is the ever popular frame lock, and there is also a heat-treated steel insert making the lock-up even stronger. Opening the blade is via a thumb disk on top of the blade, and behind that are some very aggressive serrations on the top of the handle, that are repeated on the bottom of the handle – so you have one of the best gripping areas on any knife – its not going to slip out of your hand. The whole knife only weighs in at 4.4-ounces.

I like the satin finish on the blade, very rich looking, for lack of a better word. Plus it won’t show all the scratches you’re bound to get on the blade. The whole knife is not only tactical looking, but also shines as a large Gent’s knife, too. I like it – a lot!

My Tests

I did my usual off the hand testing of this new folder, like slicing through tough blackberry vines with one swipe of the blade. Opening and cutting up cardboard boxes – this stuff is really tough on a knife blade and dulls them quickly – but the cardboard boxes were no challenge. Also, used around the kitchen and at the kitchen table for cutting various foods, and any other cutting chores that came along on the homestead. One tough material is poly rope, and if you don’t have a keen edge on your knife blade, it will slide right off of this material. The ZT 0640 was up to all the challenges that I put it through.

I will say that this folder really balanced nicely in my hand – just felt “right” – one of those things that’s hard to explain, but easy to understand once you pick the knife up. When I was a kid, it was always important to us, as to how well a knife balanced in our hand. Again, hard to understand, but easy to comprehend once you hold the knife.

This is one of my favorite folders to come into my hands from Zero Tolerance, and it pains me to say, I somehow lost this folder – and I have no clue where it ran off to. I was sure it was in my truck, in or around the driver’s seat – such was not the case, though. I’ve tested thousands of knives over the years, and that’s no lie, and I’ve lost more than my share – and what kills me is that it is usually the more expensive knives that take a hike on me. I will be replacing this folder, once I get the funds in-hand to do so – I liked it “that” much. Its not often I want to replace a knife I lost, because I always have more sitting in the wings, waiting to that the place of the AWOL knife. In this case, I need to replace this folder, it just grew on me for some reason.

I won’t say this ZT is inexpensive, nor will I say it was too expensive…it retails for $248, but if you shop the ‘net you can find it at a better price… Check one out, it will be hard to put it down and walk away from it.


  1. I would like to know which SAK you used that came to pieces by using it with which amount of force?

    I carry SAK`s for years and i´d never one break on me, but i never abused one on super hard Tasks , i wouldn´t expect a KA BAR or Glock to survive that either, nor even hard ones.

    1. I don’t think Mr. Cascio was picking on a particular brand of Swiss Army Knife; that title has been applied to all manner if knives that resemble the originals made in Switzerland. It’s possible he has focusing his comment to cheap knock off versions. I used to be a Victorinox dealer and hands down they are some of the best built knives on the market and are THE true Swiss Army Knives. Wenger is now part ofnthe same company. I sold many and the only breakage I ever saw was when a customer used the blade and excessive force to try to pry something apart. Blades are for cutting, not prying. Anyway, I’ve had several Victorinox and Wenger SWKs in my collection for decades and one is a daily carry for 30 years. Never a problem and all the tools work just fine today. It really is hard to beat a Victorinox, especially their larger folders.

      That said, Zero Tolerance makes very nice folders. This one appears to be a very nicely made knife and everything from materials to look and feel all seem to work well together. I almost never spend more than $75 on a folder but am looking for a knife that becomes my daily carry heavy duty knife (won’t be in my pocket, it’ll be in my backpack or on my belt because I don’t like the weight in my pockets). I’ll add this one to my list which currently has a Benchmade, Spyderco, Kershaw and now Zero Tolerance on it. My opinion only but every man who is interested in self sufficiency should own one high quality folder.

      I picked up a G96 at a second hand shop for $12 with leather sheath and refinished to like new condition. Made in Patterson NJ and the steel really holds an edge beatifully. They resemble the Buck 110 folder. Sometimes a good used knife feels just as good in the hand. If you can’t afford a top quality folder like the one Mr Cascio is recommending then keep your eyes open. I find mine while visiting second hand and antiue stores on business trips.

      1. Hey Chris, glad to hear someone say something positive about Swiss Army knives. I’ve been carrying a Tinker for 40+ years and couldn’t live without it. Just the right size so I hardly notice it in my front pocket. I don’t even own a can opener in the house because I can have my Tinker out and deployed before I could even get a kitchen drawer opened. The toothpick, of course, is the best part of it. Actually lost the key to my kipper snacks one time on a backpacking trip so the one on the awl worked like a charm.

        I do have 15 other knives, but for everyday practicality, nothing beats the Tinker for me. Easy to hide from TSA scanners as well! 🙂

      2. I called these the loss loaners as I like to carry them to Events and if they got lost, but these aren´t [genuine] Swiss Army Knives (SAKs).

        Yesterday I took the small SAK in my Hands my grandma gifted me for my first Scandinavian camping trip in my Teens. I opened cans for 20 people with it over 30 years ago

  2. This was a good honest article about ZT. I have owned 3 of them. I, like you lost one and quickly replaced it with another. I am 71yoa and have used knives since I was 8yoa. A Barlow was my first one and I still have it. Now, about these knives, I have a heavy duty one, model 0350 that is a tank. Great for my bugout bag if needed but usually carried around the homestead. My other model is a 0450, and is great because of the lightweight and size. It handles most chores around the house. The quality of these knives is absolutely the best I have ever owned. They are the most expensive also. I was buying german pumas in the 70s for $35 and up. They still are great knives to compare to. I have learned a blade must have vanadium in it to hold an edge. And that they do. I agree with your assessment of the blade steel and modern methods.

  3. “Sure, some are made overseas, but made under strict quality control, and they are not made in slave labor factories.” Then why are they made overseas??

      1. Sorry, many Kershaw knives are made in communist China… slaves labour, cheap labour… Cold Steel Bushman – also made in communist China…Taiwan is very different, another quality…
        I stick with my Victorinox Camper from 2011… 0 problems… and with Victorinox SwissTool X – perfect, lifetime warranty.

  4. Thanks for the review Pat. I’ve got an older 0301 that is part of my EDC sling pack.
    I get a chuckle whenever I see it. It rattles when you shake it. Once it’s open, it’s solid as a rock.
    It’s just a solid piece of kit that I can rely on.

  5. I’ll stick with my Leathermans for the repairs when I’m on the road, and Benchmade for the pocket carry. If by chance I need to open any cans then an old P-51 is still hanging on my key chain.

Comments are closed.