Differences between the Extrema Ratio ONTOS and the new ONTOS II

 Understanding the Differences between the Extrema Ratio ONTOS and the New ONTOS II

Let's take a look at them!

Above, the mighty Extrema Ratio ONTOS

(Black oxide MilSpec coating)

Seen above here: The New Extrema Ratio ONTOS II (shown is the N690 Expeditions version, there is also a Böhler S600 Tungsten alloy version as well-more on this later) . 

So what's the difference?

In order to understand the difference between these 2 models we will discuss the finer points of the original ONTOS, a knife which is still a current model from Extrema Ratio.

The Ontos was conceived as a hardcore military survival type knife 

and as such it's design reflects this. A Western styled Tanto, which had a convex ground edge placed upon it. The main part of the blade however is not totally straight and has the slightest curvature to it; combine this with a similar slight curvature of the tip cutting section and you have a formidable cutting piece. 

In order for excessive strength capabilities, the blade width is 6mm and a type of sabre grind, with the spine being reduced in two  key regions, (see below)

one just behind the tip to give this model fair to good penetrative abilities despite it's blade thickness. The spine is further reduced in a region after the hilt where alternating serrations have been placed, 

enabling it's capacity to quickly cut cords. The ONTOS is extremely capable of hard tasks and due to it's overall weight can also be used to chop effortlessly. 

Before I go any further, if you have not seen my extensive reviews of the ONTOS over the years then please check them out under the Play list of Extrema Ratio knives @BushCampingTools.

 

The geometry of the ONTOS is thus totally suited for such tasks as chopping hacking, cutting, levering, hammering, skinning and butchering, along with fire starting tasks. With a hand ground convex edge, the knife edge retains good functionality with heavy work on dirty objects and can easily be maintained in the field. 

The Ontos comes with an option to attach a small pouch which one can place a "survival kit" and diamond sharpening plate. I of course got rid of most of the stuff in this tin and replaced it with my own materials. Needless to say it is fully Molle compatible and also features a leg strap and like all of their scabbards there is much attention drawn to the quality of the stitching and robust nature of their design.

Now what about the new ONTOS II?

Above image showing the Böhler S600 version of the ONTOS II

Ok, so other than a name change, I feel the ONTOS II is a totally different knife 

than that of the ONTOS. It has been designed for an entirely different market/end use. (Teflon coated)

For a start, the blade features a full flat grind which by default results in a substantially thinner profile than that of the ONTOS. 

Blade Coatings

There are about 5 different industrial types of Teflon coatings for steel. Of these 5 it is unknown to me at present which formulation Extrema Ratio are using. When i find out i will publish it here!

One notices the blade is lighter in the hand 

and this of course has it's benefits for a knife which is practical to be used all day and not just brought out for an imminent survival situation and or emergency. Plus working with the knife at shoulder height or above there will be less fatigues, simple things like this can matter under some circumstances.

The Blade of the ONTOS II has been re-engineered for cutting tasks. The tip is no longer that of a Western styled Tanto and more of drop point with good curvature which will allow for use as a skinning knife (if you had to). The ONTOS II is not a knife for levering with like the ONTOS, where the full width of the tang/spine proceeds almost to the tip of the knife.

The serrations have disappeared and this region can now be used to break dead wood without unnecessarily dulling the primary knife edge (see my Kizlyar Supreme Survival knife reviews where Kizlyar Supreme also feature such a section on their spine of their survival knife). It is not (as comes from the factory) acute enough to strike a steel against.

They (Extrema Ratio) have however left a good chunk of spine unaltered in order to provide a flat surface for light hammering and or striking surface for a baton. However, the ONTOS II 

is now basically in the large "camp knife" category- yes it can like all large knives be used in a "survival situation but why would you since if you plan to stay on a deserted tropical island (as I have) you would instead choose the Ontos as weight is not a consideration if one is not on the move.

With 2 options available, a N690 "Expeditions" model, equipped with molle/pals compatible sheath and a Malice strapped pouch and fire steel, what more do you want for your camping/hiking trip? Ok, so what more do you want?

How about the S600 Tungsten alloy tool steel version? What on earth are you are talking about??? PROVEN INDUSTRIAL GRADE STEEL!!!

Well here's the scenario, you like going out into the wilderness, you will be cutting stuff, all sorts of stuff and you want to move as light as you can for as long as you can then you may not take a sharpening device with you want an edge which will hold up against the most abrasive stuff you can throw at it like cutting mushrooms close to the ground where there is a high probability of the edge contacting stones etc. 

Then you want to process some wood and the only wood is stuff laying on the ground. This wood will never be as clean and free of dirt like fresh sawn timber or dead wood still on the tree, plus you may not have a choice here. Essentially you are taking a big knife made with a steel, of whose edge will resist damage to a greater extent better than N690 all things being equal. 

Now just imagine that all that dead wood laying around is extremely hard, say for example: Eucalyptus and or acacia wood (found across most of Australia), or other hardwood species elsewhere. All knives can stay sharp when cutting into green live timber but how well will they stay sharp cutting in well-seasoned hardwoods off the ground? The more resistant the edge to dulling (all things being equal) the longer it will stay sharp. That's physics!

 How about camping on the coast for a while and having to cut sand impregnated marine ropes washed ashore? Gutting fish all the time etc. The higher the HRC the longer that edge will stay sharp.

Now you are saying, heck why no just harden N690 to over 60HRC? Well if one does this, any stainless properties will go out the window because the higher the HRC for N690 the less resistance it has to corrosion and heck that's why you would choose N690 for such a knife if you plan on working in wet/damp conditions all the time and not a high probability of keeping the blade dry, then this might be the case just to use a HRC 58 knife. That being said, S600 is not as resistant to corrosion, and one should keep it dry. 

So where will S600 shine? 

Firstly, let me say the S600 is an industrially proven steel alloy routinely used as cutting cutting tools for the hardest of materials in high speed tooling.

It is capable of being hardened to very high Rockwell values and retain it's toughness characteristics. Where as many steel alloys can be given a high Rockwell value, not all are actually designed for such high values without a compromise to overall toughness loss and hence a increase in brittleness. For example: Crucible (CPM) did not recommend a HRC range above 60 for 3V but Benchmade for example created knives with HRC greater than 60. I'm certain there are trade offs here with decreased toughness and this is exactly what CPM indicated. So here we have with Böhler's S600, a tool steel designed to be hardened right up to HRC67!

So back that question, where will S600 shine?

Just one of many examples might be: in dry dusty (and hence abrasive) environments 

(and as mentioned above re cutting seasoned hardwoods), where little or no water can be wasted just to sharpen a knife. So in other words an arid/desert (as an example but of course not limited to) environment. So one's knife edge needs to stay sharp for longer in between being able to actually put it against a stone/device. 

There are of course trade offs with all high HRC knife steels and that is it will, by physics, take longer to sharpen compared with a lower HRC56-58 hardened and tempered blades, especially if carelessly allowed to go blunt. With S600 it has a proven edge stability-after all it is a tool steel which is used to cut other metals including other steels!

So if you don't know, what is in Böhler's S600?

So taken directly from Böhler's site (remembering here they are talking about these features in relation to cutting metals- NOT organic materials).

Just look at that elemental composition! It is of course the high Molybdenum (Mo), Vanadium (V) and Tungsten (W) percentages which give the S600 it's amazing characteristics and partake in carbide formation with the Mo also contributing to the overall toughness.  S600 is an alloy which can of course be hardened in the vicinity of HRC 65-67! at a tempering temperature of 540C, however, in the case of the Extrema Ratio ONTOS II S600, we have a more respectable and practical HRC of approx: 64, which is super hard but not insanely hard!  The S600 has also been cryogenically treated for optimal grain structure. Vanadium carbide generation and WC generation provide the basis for wear resistance with Mo improving the toughness.

More to come in the field so stick around!

BCT

MORE here!

This conclusion taken from the following Journal:

Journal of Materials Research and Technology

Volume 26, September–October 2023, Pages 6462-6475

Please note that the alloy in question is NOT S600 but AISI M2 which is the closet equivalent to Böhler S600. 

The austenitization temperature is the most influencing variable on toughness.

When accompanied by a proper combination of austenitizing and tempering cycles, the CT contributes to the enhancement of the impact toughness and the wear resistance of the AISI M2 tool steel.

The selection of 1185 °C for austenitization, 520 °C for tempering, and the use of Cryogenic Treatment is an excellent option to improve the Toughness of M2 steel.

The selection from 1185 °C to 1200 °C for Austenitization, 520 °C for tempering, and the use of 28 h Cryogenic Treatment or even higher is a good option to improve the wear resistance of M2 steel.

Cryogenic Treatment allows improving both wear resistance and impact toughness.

Linder knives SUPER EDGE 8 Worker

 WANGER Linder knives SUPER EDGE 8 Worker

Fully made in SOLINGEN Germany!

The Linder SUPER EDGE 8 WORKER is one seriously heavy duty western styled tanto blade made with Japanese Hitachi ATS-34 steel. 

The edge is as described "SUPER" and the proof is in the pudding as they say, this particular knife of mine did the following:

Yes, that's right, this essentially 5mm thick blade 

it sliced straight through that chunk of brass you see in the upper image, with no noticeable damage to the edge of the blade, either visually by eye or by running one's thumbnail across the edge to detect any evidence of edge damage! 

This knife of mine was on display at this years IWA 2025 at the Dirk Wanger Linder stand. Dirk kindly "donated" it to the cause!

The Linder SUPER EDGE 8 WORKER comes in either a black TPE grip 

or Linder's blaze orange TPE which they call "Easy Track" coloration. 

TPE is highly chemical resistant and this grip is super ergonomic. The original LINDER company worked hard to design and produce such a grip, which BTW has a keyway-ed tang and the lanyard hole liner goes all the way through the tang. So there is no chance of the handle parting company with the blade.

The Linder SUPER EDGE 8 WORKER design is from Dominik Graf and bears his logo of the "bear paw". 

The HRC is between 60-61 and the ATS-34 has  been vacuum hardened and cryogenically treated for optimal microstructure.

From my experience with many of the Linder range both prior to Dirk's acquisition and his own models of the Super edge series, these ATS-34 knives are super performers.

The Linder SUPER EDGE 8 WORKER has been designed with "heavy duty use" in mind and as such the tip is capable of extracting "buried arrowheads" from that tree "that got in the way" on that archery trip last week! 

Although, all jokes aside I don't plan on planting any of my arrows into any trees on the next archery trip, although, it's always possible and I have done it on one occasion when the arrow passed clean through a wild goat (dropping the goat where it stood) and embedded itself into (of course) the only tree stump to be found! Being in Australia, where those tree stumps seem to made out of steel, the spring steel of my broad head was, believe it or not, no longer in any way shape or form going to be used for hunting again!

Ok, so with this heavy duty western styled tanto tip this knife begs to used and is no show piece! 

There is a no nonsense Kydex scabbard and "Tek Lok style" quick release belt clip. The security of the knife within this scabbard is very good and inserting this knife you can feel a positive lock up.

The Geometry

The Wanger Linder Super Edge 8 Worker (that's a mouthful!!) main edge is ever so slightly curved. The blade itself represents a sabre grind and the full thickness of the spine occupies a little over half of the width of this blade, thus a very strongly constructed blade.

As mentioned the steel of choice here is Hitachi's ATS-34, a well-proven martensitic stainless steel capable of great HRC. These models hardened to HRC 60-61. The edge is bevelled and there are almost no noticeable grinding marks when using a X10 hand lens to examine the edge.

Whilst the milling marks are clearly visible under high magnification of approximately X12  magnification, the edges are free of grinding marks (but not dust LOL!).

Despite being a big chunk of 5mm ATS-34, this knife has great balance and feels very sturdy in the hand. 

This knife also came with a small fire steel. You'll see it later, nothing great to write home about but none the less it was housed in a kydex mini sheath. No striker as the spine of the Super Edge 8 Worker is acute enough to strike ANY steel.

It was pleasure to collaborate with Linder knives those years back and it came as a semi-shock at the time to hear that they had closed their doors. I say "semi" because it was clear the writing was on the wall when the company who had a long standing history as a manufacturer in Solingen started to sell other companies knives. It was however fantastic news to see that production has not only continued but a new injection of designs and ideas have arisen with the Wanger Linder name we see today and the continuation of the Super Edge series and as was evidenced at the Wanger Linder booth at IWA 2025 just recently in Germany.

I was a firm believer that the "Super Edge series" was what the original Linder needed to take them into the modern market place, keeping the usefulness of models designed to be used and not just looked at. Few production knives have come my way which were deadly sharp out of the box, so sharp I've managed to cut myself by a few clumsy moves, Linder and Wanger Linder knives were/are in that category.

Field reviews coming soon......

BCT

10 Great Hunting Knives Everyone Should Own At Least One of Them

 

10 Great Hunting Knives Everyone Should Own at least one of them!

by @BushcampingTools

Here's a list of knives I think are absolutely great for hunting up to medium sized game. By this, I mean Wild goats to Pigs. With these knives you will be able to: gut, skin and butcher along with possibly (knife dependent) some more arduous tasks such as preparing an area to perform such duties and or camping with the same knife. 

There is no preferential order to which I ascribe my reasoning to these knives. One is certain to find at least one of these knives right for their hunting purposes. The list is by no means extensive and also a tiny fraction of the knives I have used for such purposes. With Shot Show 2025 just finished and now IWA 2025 coming soon. I'm sure many are now  "In the groove" and now ready geared up for hunting!

Ok let's begin:

Benchmade Leuku ( Steel CPM 3V)

Reasons: Easily cleaned, non slip grip, stainless steel, excellent edge retention (A bit harder to sharpen from blunt remember!-don't let your knife edges go blunt!). Can do all tasks (except cutting down branches and trees). Lightweight (in the handle-to reduce wrist fatigue). No nonsense leather and hard plastic lined scabbard- traditional carry system-added bonus of a fire steel carry loop (Fire steel, not included).

Maintenance level: Low

Why?: Proven modern rendition of the Laplander's Leuku,-say no more.

Cuts like: Very well/Like no tomorrow

Fox Knives FX-143 MB "Perser" (Steel NIOLOX)

Reasons: Comfortable and stylish at the same time, that will surely catch the eye of a fellow hunter who does NOT own this blade. Niolox steel, a proven industrial cutting steel in the food industry. Featuring high Niobium content of around up to 0.8% Nb, high carbon 0.8%, high vanadium 0.9% and high Mo at 1.1%. It goes without saying this is a high corrosion resistant high edge retention steel.

Comes with a stylish but simple full leather scabbard, traditional belt carry, 

Note: Maybe not for big hands (eg bigger than 8.5). A tad too small for med game on the large side for butchering one would require a longer blade.

Why?: Easily gripped, full hand control for fine skinning tasks. Blade shape great for skinning and gutting. If this was a bigger knife with same grip, I would not like the grip for hunting as it's just too smooth but as it is it can easily be held. But the blade shape is great.

Cuts like: No tomorrow

Maintenance level: Low to medium (scales can not be removed). NIOLOX is not indestructible.

Extrema Ratio Sethlans (Steel Böhler N690)

Reasons: A classic small drop point design, sturdy construction, lightweight stainless blade (front end), Good design for multiple finger positions. 

Why: Proven drop point design, comfortable grip, knife is supplied as a "package" which includes everything one needs to pack in to the hunting site on foot, ie a fire steel and good quality fine ceramic and diamond sharpening stone all within a multi-mount scabbard system. Their experience in designing carry systems for military personal is of great bonus for the hunter for this particular blade.Secure kydex carry system.

Maintenance level: Low to possibly medium but the medium refers to the scabbard to keep clean, although the protective insert of kydex is easily cleaned of blood and guts, treat the nylon part as necessary, ie wash it if it gets covered in blood etc.

Cuts like: Very well/Like no tomorrow

Kizlyar Supreme URAL (Steel Böhler Sleipner tool steel)

Reasons: Heavy duty but still of small to medium sized blade. Convex edge, excellent edge retention with indestructible** Sleipner steel. Non stainless, easy to field maintain. Comfortable grip, supplied with a traditional carry (but versatile) leather scabbard with a Fire steel loop (fire steel not included) and belt dangler system. Made in Russia, maybe hard to acquire for the present?

Cuts like: no tomorrow.

Why?: Full Convex grind to edge, can easily perform many camp tasks with this blade, light weight blade, comfortable non-slip grip.  

** Ok nothing is indestructible!

Linder knives Super Edge 5 (Steel Hitachi ATS-34*)

Reasons: 

This is a superb and simple design which just works, comfortable and ergonomic in any hands. Linder achieves a hair popping sharp edge and a heat treatment which holds a super edge (no pun intended!). The knife is light in the hand due to it's construction and it is also light in the blade despite its 4.8mm thickness. Easy track (fluorescent orange) handle in TPE, almost impossible to lose in low light conditions (but highly steal-able LOL!).

Comes with a no nonsense easily cleaned (from blood and guts) scabbard.

Why?: This is a "working knife" and as such sports a "rubber" grip. It's meant to be used and designed as such. The tang goes all the way to the lanyard hole and has several "keyways" to prevent the grip from parting company with the knife.

Maintenance: Low

*As far as I'm aware Hitachi no longer make ATS-34 and thus if this is true, then all knives being made from this steel will be of limited production runs. Certainly other manufactures have told me including Linder that they are using "old stock" of ATS-34. Does this spell a collector's item????? I'll leave that for you to decide.

Work Tuff Gear Red Wolf (Steel Böhler's K329)

Reasons: The Red Wolf is an in house Work Tuff Gear design. It is a superb design and this is reflected (no pun intended) in the finish of this blade, which sports a super mirror polished convex edge to a full flat grind. The handle scales are non-slip. Modern aesthetics in design, such as a concealed lanyard hole, simple but very secure pancake style Kydex scabbard, Possibly Work Tuff Gear's best all round hunting knife to date? Like the Kizlyar Supreme URAL, this knife can do all but the heaviest tasks required for both hunting and camping, packing in to the site.

Why?: I just said it! But without talking price, very affordable high quality knife IMHO.

Kizlyar Supreme Severus (D2 tool steel)

Reasons: Proven edge retention of D2 tool steel, blaze orange G10 scales, scalloped milling pattern for a total non slip grip, so important for hunting purposes. Simple well constructed leather scabbard, highly affordable, working knife with a classic blade design. Excellent factory edge. Can be used for gutting fish as well due to the great tip.

Why?: Reasonable cost, Russian quality made, deadly sharp out of the box, light in the hand.

Maintenance level: Low to medium (scales can be removed).

Fox knives FKMD    RIMOR (Steel Böhler's N690)

Reasons: This is a largish field knife with hunting capabilities due to the multiple hand positions available and the specific blade design, enabling gutting, skinning and ease to butcher all medium sized game right up to large game but without being a super big knife. 

The RIMOR can function both as a sturdy camp knife as well so this is definitely a one knife solution, although remembering one knife may not function well in all situations. For example: the RIMOR is not great for fishing (clearly) although it can be done of course.  The belly section allows it to be used as a skinning knife despite it's size. The robustness of the blade also allows for it's use for remote hunting where a saw, hatchet or large knife may need to considered and the hatchet looses out to the RIMOR?

Why: No nonsense grippy handle which totally encloses the tang, thus can be used like the other fully enclosed handled knives listed above, in sub zero weather/no gloves. More of a "Survival/Multipurpose" knife than a specific hunting knife, however, the blade design lends itself to hunting purposes, unlike many multipurpose knives which are not suitable for hunting.

Maintenance level: Low to medium

Cuts like: No tomorrow

Kizlyar Supreme Yeti (Steel PGK)

Reasons: A light weight full flat grind super sharp hunting knife made with PGK steel. PGK steel is a very interesting steel in regards to its composition. A very high carbon content along with high Tungsten, Mo and V plus at the same time 8.5% Chromium! All of these elements make for excellent edge retention. The Yeti certainly excelled with edge retention field testing. 

The knife is comfortable to hold for long periods and combined with a light blade, will not tire your hands during gutting, and skinning. The YETI can function well around the campsite for ALL food preparation with ease due to it's overall geometry.

The knife is supplied with a traditional styled leather scabbard which includes a fire steel loop (fire steel is not included) and also an included belt dangler for those who need a longer reach.

Why?: Because of the use of PGK steel it is possible for Kizlyar Supreme to produce a thinner blade but at the same time very strong with a capacity for excellent edge retention from the high vanadium content. A lighter weight hunting knife most suited for long trips and less maintenance time sharpening. 

Maintenance level: Low to medium

Cuts like: No tomorrow

Linder knives Trapper  (Steel 440A) Sadly no longer made!

Reasons: Stylish, robust, well-made (looks like a hunting knife!), deadly sharp Traditional German made in Solingen, comfortable, all tasks covered. If you don't own a PUMA 1974 era PUMA Hunter's Friend (PUMASTEEL High carbon) hunting knife, like I happen to own (from a kid from early hunting and camping days) then this would have been the slightly modern version of that knife which I believe actually pre dates the Hunter's Friend, although I'll stand corrected over this if anyone knows differently. The Linder Trapper is a damn good knife for hunting full stop.

Why?: All of the above, plus a robust design allowing for all work on a carcass (see my full review and field videos about this classic knife)


Cuts like: Extremely well to Like no tomorrow

Maintenance level: Medium to high due to the cocobolo scales, wooden scales require the proper attention and such a knife is not for the clumsy or careless (with gear) hunter. This is a knife for those who appreciate the whole hunting scene IMHO. At the same time do not be afraid to use this knife heavily (if you own one or if you are lucky enough to obtain one).

Ok I'm going to wrap this up here. There are many more great hunting knives from my collection of (very used LOL) knives, such as this old Linder model below and later I will also write something about these other great hunting knives, so stay tuned!

BCT