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Carothers Performance Knives Heavy Duty Field Knife (HDFK aka NASK)

Discussion in 'Knife Reviews & Testing' started by abbydaddy, Sep 30, 2017.

  1. abbydaddy

    abbydaddy Gold Member Gold Member

    Oct 14, 2014
    Today I have a review of the Carothers Performance Knives Heavy Duty Field Knife (CPK HDFK, aka NASK). As per usual, you can read this review on my blog, but I have all of the pictures and content here too.

    The Carothers Performance Knives - Heavy Duty Field Knife (AKA: CPK HDFK)

    This is a review of the newly released Carothers Performance Knives Heavy Duty Field knife (CPK HDFK), or if you hang out on the Carothers Performance Knives forum this knife is perhaps better known as the NASK, for Not A Survival Knife (a nickname derived from a desire to avoid confusion with Survive! Knives). This is a knife designed to be an indestructible heavy use knife that can be a one-knife solution for all your survival needs. While I am not a "one-knife-to-do-everything" kind of guy, I do enjoy reviewing survival knives. And of the knives I have reviewed and used in this class, none of them have performed better overall. This really is a superbly designed indestructible everything knife.

    I was fortunate enough to land one of the D2 Prototypes of the HDFK pattern. The D2 (Actually PSF 27, a spray formed version of D2 made by SBSM) prototype version differs from the regular production version in a few ways beyond the steel (the regular version will be in D3V). The blade is "Sterile" which means that it doesn't have the maker or designer marks that will be found on the regular production versions. Additionally, the "bark" was left on the sides of the blade for a less refined looking finish. I tend to prefer a more polished level of finish, but I have to admit the rugged finish looked pretty cool. The only marking on the blade was a simple D2 to let you know what steel this was made with. I only had two weeks to review this knife before I had to send it on to its permanent owner, but I made sure to give it a thorough workout.


    As one can see looking at this knife, the design legacy shares many elements with the CPK Light Chopper. But even though there is a great deal of visual similarity, this knife functions very differently in pretty much every type of use I put it to. The knife is also much smaller than the Light Chopper. As the company and designer of this knife are the same as my recent CPK LC review, I will quote myself:

    The knife is made by Carothers Performance Knives, which is headed by Nathan Carothers (and his wife Jo). Nathan Carothers is a very experienced machinist, with a vast materials knowledge, as well as a truly impressive capability at using CNC machining. He is also very willing to share his knowledge, I have learned a lot over the last year and a half or so paying attention to Carothers (Here is a BladeForums thread of people asking Nathan questions and him answering, it is educational and about 50 pages long). CPK is an exciting brand to pay attention to, but at the current time demand is far exceeding their production capability which makes it hard to get a lot of CPK knives. Sales for the Light Chopper (for example) are typically for 20 or so at a time, and they usually sell out in less than 5 seconds. The other option is to buy the knives on the secondary market (which is how I purchased the reviewed knife), but prices can vary dramatically, and availability is still limited.

    The knife was designed in cooperation with Lorien Arnold, a talented knife designer from British Columbia, Canada. Lorien cooperates with numerous knife makers, but has been partnering extensively with CPK recently. Sadly I can't afford the custom knives he designs, but I am a fan nonetheless.

    The TL;DR review summary:
    I do not know of a better quality survival knife, regardless of price. This knife really impressed me. For any given purpose there are better knife options available, but for an all purpose knife that can stand up to significant abuse, I have not used a knife that handles as many tasks as well as this one. Like any CPK knife, this one is hard to acquire, but it is well worth the cost and trouble if you are looking for a survival knife.
    Last edited: Sep 30, 2017
    kingdmx3, Oyster, supertac916 and 5 others like this.
  2. abbydaddy

    abbydaddy Gold Member Gold Member

    Oct 14, 2014
    Let's Start With the Specs:
    (Specs from the CPK HDFK D2 Prototype sales thread)
    PSF 27 D2, tested 61-62 HRC, .220" thick at ricasso
    Total length 11.825"
    Blade length 6.5"”
    Weight 12.8 oz
    Grippy 3D machined scales in micarta
    Black oxide treated 18-8 stainless steel fasteners

    Fortunately for the purposes of this review, the HDFK was almost exactly the same length as my Spartan Harsey Difensa, this was handy since it meant that direct comparisons to a very comparable knife were easy to make. The Difensa has been my go to knife for survival knife comparisons, so I have been able to compare it to other knives like the Ambush Alpha and the Fiddleback Forge Bushfinger, which means that I am able to contrast performance across multiple similar knives from a standard baseline.


    The handle of the HDFK is made of unbuffed black canvas micarta. Micarta is made by layering textiles (canvas, linen, or paper usually) with phenolic resin and compressing them. The unbuffed micarta is less shiny and grippier. As I have written in numerous other reviews, I really like micartas in general, and canvas micarta is probably my favorite high performing handle material. To me, micarta feels warm in the hand, like wood, and even though it is actually a very hard material, it somehow feels soft in my hand (at least when shaped well). But one of my favorite things about an unsealed canvas micarta, is that the tiny bit of exposed textile ends actually make micarta grippier when wet. Not a ton grippier (after all most of the resin soaked textile is impermiable), it is just the very surface that is affected, but it is a nice feature. From a materials perspective, as a user, unbuffed canvas micarta is hard to beat in my book.


    The steel is PSF-27 D2. This is a steel I had absolutely no prior experience with. D2 is a not-quite-stainless tool steel used fairly commonly in cutlery. Despite that fact, I had not previously used any sort of D2 steel knife, so I have no baseline for the steel. PSF-27 is a special version of D2. It is the same alloy (same combination of elements make up the steel) as D2, however it is spray-formed, rather than ingot formed or particle metallurgy. As I disclaim in all of my reviews, I am not a metallurgist. Spray-forming may not be the same as particle metallurgy, but from my knowledge level I will at least call this a metallurgy-magic steel, if not a science-magic particle steel. According to Nathan Carothers, this version of D2, with the correct heat treat, offers some significant toughness advantages over standard D2, though it is less tough overall than D3V (D3V will be the standard steel for this knife model).

    The metal stock that this knife is made of is pretty thick. I have certainly seen thicker knives, but this is a stout blade. The stock is 0.220 inches thick, or very close to a quarter inch. It is almost 25% thicker than the stock for the Light Chopper or the Difensa. Despite being significantly thicker, the HDFK only weighs 1.5oz more than the Difensa, presumably thanks to the fullering and skeletonization of the handle.

    The CPK Light Chopper (left) and the CPK HDFK (right)

    The Spartan Harsey Difensa (top) and CPK HDFK (bottom)

    A Note on the Sheath:

    This knife comes with a high quality Kydex sheath made by Mashed Cat. The two options offered were Tek-Lok or a dangler. Since I had tried (and not really liked) the Tek-Lok in the past, I opted for the dangler sheath. This was my first experience with a dangler sheath, and I have to admit, I was not thrilled with it. It turns out I really prefer a traditional drop loop style sheath. The dangler felt like it swung a little too freely for me, so I tried to make a field expedient thigh strap out of paracord, but that had a tendency to slide down to my knee while I was working, which would then pull down my pants. So I went back to letting it swing free, which made the knife a little harder to draw. Despite my issues with the way the sheath attached to my belt, the Kydex work was really well done. Very secure retention with a satisfying click. If I had been keeping the knife long term I probably would have purchased a Drop Loop from Mashed Cat. One of the advantages of a Kydex style sheath is the modularity that lets you swap out parts. A drop loop only costs $15, which would be totally worth it in my opinion.



    The sheath with my paracord leg loop.

    Another option could be a custom sheath. I recently purchased a custom leather sheath from a fellow who goes by Grogimus. With a knife like this it is not unreasonable to invest in a sheath made exactly how you want it. I was happy with Grog's work and interactions on the CPK LC sheath he made for me. I will post a review of that sheath soon.
    Last edited: Sep 30, 2017
  3. abbydaddy

    abbydaddy Gold Member Gold Member

    Oct 14, 2014

    Comparing the PSF-27 steel to my experiences with CPK's D3V, I have to say I prefer the D3V. When the HDFK came to me from Carothers Performance Knives the knife was quite possibly the sharpest knife I had ever handled:


    The HDFK shaved my arm so cleanly that the picture above had to be semi-staged. The knife wasn't just shaving sharp, it was hair popping sharp, the hair just flew off my arm, I had to pick it up to show in the picture. After two weeks of intense (but not abusive) use, the HDFK was no longer shaving sharp, and I felt that edge degradation due to lateral stresses from wood working were evident (though I did not have a macro-lens adequate to show what I mean). The knife was still sharp enough to cut ripe tomatoes without crushing them (so let's be clear, I am being very picky), but the drop off in sharpness was noticeable. I compare that with the D3V of the Light Chopper, which was never quite as sharp, but even after more than a month of (less intensive) use still shaved hair.

    But the D2 is still impressive. I used the HDFK for pretty much everything. I chopped with it, cooked with it, feather-sticked with it, split kindling with it, and shredded a shipping box with it:


    Despite all this use the knife still cut ripe tomatoes without crushing, so it holds a good edge through a lot of work.

    My biggest complaint about the steel probably has more to do with my failure to treat the steel as non-stainless. The knife spent a couple days in a pack next to a damp shirt, and that resulted in rust spots on the edge and a pepper spot on the blade. These things were not terrible, but it made me realize that I couldn't treat this steel as fully stainless, and I like low maintenance steel on a survival knife. Once again, even though D3V is not truly stainless either, based on my experiences I would opt for a D3V steel for this knife.

    Rust spots on edge

    Pepper spot on blade

    Blade Finish:
    The blade finish on this knife is a kind of unique thing. The milled primary bevels are stone-washed, but the flats of the blade retain their bark from being processed into sheets. For performance purposes the important finish is the stone-wash on the flats. It is my experience that CPK stonewashing seems to show scratches and wear a little faster than some other stone-wash finishes I have used, but that is a very subjective statement. In general, stone-wash remains one of my favorite finishes. It is a low friction, scratch hiding, reduced reflectivity finish.

    The blade design on this knife is definitely a winner in my book. The blade is nice looking and practical. The thumb ramp is well placed. The tip of the blade has plenty of belly while still having a functional point. The fuller on the blade saves weight and allows the balance of the knife to be right about at the front of the handle. There is also a finger choil to allow the user to choke up on the knife for more detailed work. Unfortunately for me, that choil isn't big enough to accommodate my... robust... fingers. After some small cuts, I had to wear gloves to make use of the choil safely.


    Another neat touch on this knife, that I never would have noticed myself, is the grind. I assumed it was just a high flat saber grind, but the grind is actually a subtle S-grind. I had no idea until I saw Nathan Carothers mention it. It is a subtle thing, and I don't have any pictures that show it, but it means that there is a little more metal behind the edge like a convex grind while also having less metal through the flats which makes slicing a little easier. It is an example of the kind of complex machining that Carothers manages.

    The handle is ergonomically excellent. The micarta was extremely grippy. They handle was comfortable to use for long periods. Like everything else about this knife, the handle is well designed and thoroughly machined and sculpted. The handles of CPK knives really need to me held to be believed.


    As always I feel the need to remind readers that I have extra-large (size 10 1/2-11) hands. Knives in my hands are usually larger than they appear.

    I am firmly of the opinion that an ergonomically superior handle is one of the most important reasons to buy an expensive knife, and yet many expensive knives have flashy looking handles that are unpleasant to use. I like to buy knives to use them, and a well designed handle is crucial to pleasurable use. My favorite designers are ones who give as much thought to the handle as to the blade, and this is a prime example of that sort of design.

    Fit and Finish:
    This prototype was marketed as being a rougher level of finish, described as "field grade." So rather than all of the surfaces being smoothed to a uniform polish before being stone-washed, the machining marks and "bark" was left on the blades. In person this level of finish was very attractive.


    There were no flaws that I identified on the knife, and no quality failures found during use. My impression of the fit and finish quality of CPK knives from the examples I have handles is that they are second to none.
  4. abbydaddy

    abbydaddy Gold Member Gold Member

    Oct 14, 2014
    Use Review:
    To simplify my use review for this knife I am dividing it up into different sorts of tasks that I used it for to compare performance to other comparable knives.

    Chopping is a use that I did not place a lot of emphasis on until I started carrying my Difensa while clearing brush. I used to be of the opinion that if you wanted to chop wood you were better off just carrying a hatchet, saw, or machete. If you are looking to process large amounts of wood that is still true, but having a knife that can handle some chopping is actually very handy. Once I started using a knife to chop smaller branches and such I really grew to like it. Now I consider chopping performance to definitely be something worth considering in a survival knife.

    Obviously the HDFK doesn't chop as well as the Light Chopper, but I thought it was a nice picture.




    The chopping performance of the HDFK was nearly identical to the Difensa as far as I could tell.

    In chopping use the HDFK was a capable chopper that performed about the same as the Difensa. It certainly isn't a machete, but it does a pretty good job. Bear in mind that the chopping performance of the Difensa was what originally convinced me that a belt knife could be useful for chopping duty, so this is very good for a comparably sized knife. It was definitely a better chopper than the Ambush Alpha or the (significantly smaller) Fiddleback Bushfinger.

    Feather Sticking:
    I am not a great featherstick maker, but I tend to use the ease with which I can make a featherstick with a knife as a proxy for how easily I can work wood overall with the knife. For me, things like a knife edge close to parallel with the handle angle are important to the ease with which I can finely control the knife edge. Additionally, the grind of the blade is very important to easy wood working. For me, nothing beats a scandi grind for most wood working tasks, though for other primary grinds a convexed terminal bevel certainly helps since a convex edge helps avoid shouldering in wood (If you want more general info on knife grinds I talk briefly about grinds in my post "Knives: A Primer," or if you just want to know about cutting geometry here is a very informative video). The complex (but so subtle I didn't notice it) S-grind of the seems to help a little in this department. It acted similarly to a convex edge in limiting the shouldering of the blade.




    All in all I was not blown away by my ability to featherstick with the HDFK. The HDFK out-performed the Difensa and Bushfinger in this area, but the Ambush Alpha definitely outperformed the HDFK. Of course my $10 Mora outperforms all of these knives in the realm of woodworking, but it can't really compete with the others in chopping, batoning, cooking, etc.

    Other Woodworking:
    The HDFK was a capable enough woodworking knife, though I wouldn't want to try to carve a spoon with it. The large size of the blade makes a lot of finer work challenging, even with the choil. But for rougher woodwork the blade handled fine.


    As an example of the importance of an edge that doesn't shoulder too much, since you can keep the edge of the blade in contact with the wood you can keep cutting with the edge rather than with force. This means that you can cut away at a branch without breaking it until the wood is pretty thin.


    For tasks like notching (important if you are building shelters or small structures for things like traps) the HDFK is an excellent choice.

    I am never going to stop being a little mystified at the popularity of batoning, but one cannot review a heavy duty knife without talking about how effectively it can be pounded through logs. Rest assured, the HDFK is an excellent kindling processor.




    I really don't stab things much, but I thought I would mention it. The point of the HDFK is not very acute. This is good for most things I would ever use the knife for, but if you are looking for a stabby knife this is probably not the knife for you. If you look at the picture below you can see that the knives are both in to about the same width, but since the Difensa has a much more acute tip the actual depth difference is about a half inch. So the Difensa went about twice as deep into the wood. I didn't stab hard. Unless you are expecting to be in close combat situations I don't think this is a particularly valuable demonstration.


    Cardboard Cutting:
    Cutting cardboard isn't really a survival task, but it is a fun way to give the cutting ability and edge retention of a knife a workout. This was a lot of fun and the HDFK did a great job. Cardboard can take an edge down pretty fast, but the D2 seemed totally unfazed by this. The super fine edge of the knife went away early in the overall testing, but the really good working edge of this knife shrugged off everything that followed. After all the testing I did the edge still cut ripe tomatoes without crushing them, and the cardboard cutting came right in the middle.

  5. abbydaddy

    abbydaddy Gold Member Gold Member

    Oct 14, 2014
    Now we get down to where the HDFK really outshone the Difensa and Alpha, the kitchen. Food preparation is very important in a camp knife. Presumably, if one is surviving one is eating. Plus, if you are just regular camping you are probably going to want to cook. And the effectiveness in the kitchen is going to reflect the knife's utility for working with game. The HDFK has a serious advantage over most other survival knives when it comes to food prep. And a big part of that is the design of the blade/guard/handle interface and angles:

    As compared to the Light Chopper, the rake of the HDFK handle is much less pronounced. This means that the blade is much easier to use on a flat surface.


    Most survival knives have large guards to protect the user. The HDFK is no exception, except the design of that guard does not hold the blade far away from flat cutting surfaces. This is very useful if you are using a cutting board, or really doing anything other than cutting away from a surface.

    I cannot over-emphasize how much of a difference having a guard that doesn't interfere with cutting makes for me. And the rake of the handle also helps a lot. This knife really worked well in the kitchen. I used this knife for everything in the kitchen, but it turns out I didn't take as many pictures as I had intended. The less acute tip makes this knife a little less useful as a petty knife than the Bushfinger, but the larger size helps in general use. This is impressive since the Bushfinger actually impressed me enough that it is in my knife block in the kitchen. The HDFK probably would not have ended up in the kitchen full time, but that is because it would be competing more with a chef's knife. For a camp cooking knife, this is a very good option.

    The HDFK works well in general use.

    It handles fine stuff well.

    It even handled peeling and cutting a butternut squash.

    I'm not going to say it was a piece of cake, but I didn't break down and use any other knife.


    This is an outstanding knife. I don't know of a better heavy duty all-purpose knife. Unavoidably for a knife of this type, other knives can out-perform this knife for a lot of tasks. But those other knives would not be able to take the abuse that this knife can take. I don't typically abuse my knives, so that isn't usually a primary consideration for me, but if I was looking for one knife to do it all, I can't think of another knife I would pick over it.

    To put it another way, before I bought this knife I set up an agreement with another fellow who would buy if from me after I did my review. I did this so that I could do my review without spending a lot of money. I figured that since I already have multiple survival knives including one that is almost the same size, that it would be silly to buy another. As soon as I started reviewing the knife I became sad that I was going to have to send it on. I really wanted to keep it. I really liked this knife, and I know the current owner is going to love it.


  6. Casinostocks

    Casinostocks Factotum Platinum Member Gold Member

    Mar 20, 2016
    Thank you AbbyDaddy for sharing your experiences and very well done Sir :thumbsup:
    abbydaddy and Brian77 like this.
  7. shinyedges

    shinyedges Unfaltering Love & Undeviating Will Platinum Member

    Jun 5, 2012
    Nathan makes a fantastic knife. Still wish I had a potato knife!

    Nice review, thank you.
    abbydaddy and Brian77 like this.
  8. Brian77

    Brian77 KnifeMaker / Craftsman / Service Provider Knifemaker / Craftsman / Service Provider

    Nov 27, 2014
    Great write up! Thanks for that.
    abbydaddy and Casinostocks like this.
  9. 91bravo

    91bravo Gold Member Gold Member

    Jun 29, 2008
    Excellent review abbydaddy! Well thought out and well executed. I am awaiting my own HDFK in D3V and reading stuff like this doesn't make the wait any easier. Thanks for sharing!
    MarriedTheMedic and abbydaddy like this.
  10. TommyGun56

    TommyGun56 Gold Member Gold Member

    Jul 29, 2014
    Detailed and very informative Review-Thanks! That Spartan Difensa is a fine knife also:p:thumbsup:
    abbydaddy likes this.
  11. Huntsman Knife Co.

    Huntsman Knife Co. KnifeMaker / Craftsman / Service Provider Knifemaker / Craftsman / Service Provider

    Sep 10, 2010
    Great review! Nathan always does it right :thumbsup:
    abbydaddy likes this.
  12. trevitrace

    trevitrace Gold Member Gold Member

    Jul 21, 2013
    Holy Andre the Giant hands! :D

    In all seriousness, as usual, fantastic and thorough write-up. :thumbsup:
    abbydaddy likes this.
  13. Mike157

    Mike157 Gold Member Gold Member

    Aug 29, 2006
    Excellent and well written review, abbydaddy. Thank you. It is appreciated. Mike
    abbydaddy likes this.
  14. abbydaddy

    abbydaddy Gold Member Gold Member

    Oct 14, 2014
    A few years back I met Bill Harsey when he visited an archaeological site I was working at. He came with a prototype of the Difensa and the Model 1. I fell in love with the Difensa. It is actually the knife that rekindled my love of knives. It took me a few years to build up to actually buying one, but that knife certainly holds a very special place in my heart. (I also broke down and bought a Model 1 not too long ago, but that Difensa is the one that won my heart first)
  15. adamlau


    Oct 13, 2002
    abbydaddy likes this.
  16. Organic556

    Organic556 Gold Member Gold Member

    Aug 30, 2015
    Very solid review. Thank you .
    abbydaddy likes this.
  17. gusbuster

    gusbuster Gold Member Gold Member

    Aug 30, 2011
    Great review! :thumbsup:
    abbydaddy likes this.
  18. ManOfSteel89

    ManOfSteel89 Gold Member Gold Member

    May 20, 2012
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  19. JustinFournier

    JustinFournier Gold Member Gold Member

    May 7, 2012
    Thanks for taking the tip to share your detailed review.

    Do you mind taking a picture of your grip which you were using while chopping please?

    The Difensa was on my list for ages but never made it home with me. I'm shocked to hear it chops nearly identically to the HDFK.

    Thanks very much!!
  20. abbydaddy

    abbydaddy Gold Member Gold Member

    Oct 14, 2014
    Unfortunately I don't have the HDFK any more, but I will take some pictures with the Difensa.

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