Knife review : XM-18 Rick Hinderer

Knives :

This review consists of :

Introductions

Copy from the maker website :

The XM-18 is known the world over as one of the toughest tactical folders regardless of your mission. Rick�s focus when designing the XM-18 was a no nonsense tactical tool ready for the simplest cutting tasks to high speed low drag operations.

The XM Series CNC flat ground Spanto blade is the best of both worlds offering maximum cutting potential in a blade that has a durable tip for prying; the blade thickness on a 3.5� XM-18 is a full .165� retaining its thickness right out to the tip. The oversized choil permits choking up on the blade for more precise work. The blade locks up on a solid � in diameter Thumb stud which is press fitted into the blade. This makes for a very strong lockup as there is no loosening of the thumb stud which can happen with two piece designs. The fact that the thumb stud locks up against the frame adds an incredible amount of strength to the sideways torque of the blade as the sideways stresses are being stopped by the whole handle side, thus relieving the stress that would normally be put on the pivot.

Speaking of the pivot, we make our own 17-4PH Stainless steel pivots on a new state of the art CNC turning center thus guarantying precise accuracy. The pivot is a �� in barrel diameter with a 3/8� head. The pivot is drilled and tapped completely through and is mated with an In house designed screw. This system makes for an incredibly strong pivot that is easy to adjust in the field. The XM folder handle shape is designed to be very ergonomic and comfortable in a wide variety of user positions. Not everyone�s hands are the same size, and also grip varies greatly, so the ergonomic handles design is great fit for all users. The textured pattern used on the handle scale is extremely grippy but does not �bite� the hand during use. The 3D texture is designed to flow liquids (such as sweat, oils, blood, etc.) away from your skin and into the �valleys� of the texture.

The lockside is precision CNC manufactured from 6AL4V titanium featuring our Hinderer Lockbar Stabilizer. The knife can be set up for either tip up or tip down carry. The non-lock side has a .050� titanium liner with a G-10 or Carbon Fiber handle scale. These high strength materials combined with the full titanium liner add strength and rigidity. The handle scales can be easily changed by the end user if another color is desired. The standard finish on all XM folders is a highly durable tumbled/stonewash that will stand up to hard use in all environments. The handle construction is an open back design utilizing huge standoffs. The standoffs are designed to add superior strength for lateral crushing of the handle case while still allowing the blade to nestle into the handle without touching the standoffs. This gives the knife the same strength as a solid back folder while offering the ease of cleaning due to the open design.

Specifications

Basic specifications :

Initial impressions :

Comparing to a small Sebenza :

Stock testing : main

The initial sharpness was low

Some numbers :

In short it had no slicing aggression and under 50X magnification appears to have the common problem of an edge formed with coarse abrasives on a belt sander and then ran too hard and long on a buffer which rounded the edge removing all slicing ability.

In extended use carving some pine (500 slices) :

There was no damage to the edge, however that would be very unexpected given the very high edge angle. This is mainly a very low level check on edge durability and edge retention but mainly to look at ergonomics in extended used. The cutting was done both

There were a few issues with ergonoimcs, some ovbious and a couple not immediately obvious :

Carving wood, compared to the #1260 Mora, making 1" points on 1.5"x0.5" pine using fairly low force 10-20 lbs, the performance difference was very dramatic as seen in the picture on the right showing the large difference in chip size.

Being more specific, through ten points the knives required to make a point

From a geometry perspective the performance should be similar to the edge angle ratio and thus it would be expected that it would be close to 2:1 (as the angle on the Hinderer is approximately twice that of the Mora) however it is actually higher showing the effect of the lower sharpness on the Hinderer.

Using the same wood but ramping up the force used to 60-80 lbs, both knives of course cut much deeper into the wood but again as noted in the picture in the right there is still a large and obvious difference among the knives.

Being more specific, through ten points the knives required to make a point

With the deeper cuts the Hinderer starts to show the benefit of the primary grind which reduces the thickness behind the bevel and so it is now only about 2:1 behind the Mora. Again this shows the effect of the low sharpness as the primary grind on the Hinderer should reduce the performance to below the edge angle ratio so it should be below 2:1.

On some stock utility cutting :

The low initial sharpness and rather thick profile had a pretty significant effect as :

and much more force was required to cut the retention bands and plastic bottles.

Initial Carry

Carrying the knife for two weeks with the initial edge sharpness and angle/thickness the main problem is shown in the image at the right of a piece of carboard. It is very clear that the edges are torn rather than being cut showing the lack of slicing aggression. The same issue was seen on :

In general for any precision cutting a lot more force had to be used and a lot less control was achieved. The other downside is that the edge exhibited rather low durability and in several places was clearly reflecting light showing extensive rolling and direct denting. This however isn't likely an indication of the performance of the steel (Duratech 20CV) or heat treatment but most likely just due to the steel being over heated during sharpening by the power stropping/buffing.

The video in the right has some general commentary on the knife after the initial two week carry period. Much of what is discussed regarding cutting ability was already noted in the above, it also contains commentary on :

A few questions / points of curiosity are also rasied:

If it was not obvious it became so fairly quickly in use that this knife is designed more for utility and very heavy cutting not soft to moderate materials as the performance is fairly low in that aspect.

Sharpening and stock work repeated

With the edge sharpened to a high polish but kept at the same angle there was a dramatic improvment on the wood cutting. On the same pine as was used previously, and again through ten points the knives required to make a point :

With no sharpness disadvantage the performance is as expected given the edge angle ratio and now the primary grind of the Hinderer starts to compensate for the thicker edge and thus it is only about 50% behind the Mora on heavy cutting were it was more than 2:1 behind initially.

As noted in the picture on the right the chips now cut my the XM-18 are much larger showing the difference of a high sharpness in wood cutting.

Extended carry

Even with the edge fully sharpened, the cutting ability is fairly low due to the thicker cross section which induces high binding forces on the blade and strong counter forces in the cutting. In general the only cutting that the XM-18 does well with the as-boxed configuration is where either :

In those cases the cutting ability is mainly on sharpness alone and not significantly dependent on cross section and thus the XM-18 is fairly useful as a cutting tool.

Carrying the knife for an extended period of time it became obvious that the true niche where the XM-18 became useful, or more so than a knife such as the Opinel were on tasks non-cutting type work where the knife is used to dig/pry. For example digging out the strap / stopper on a can of olive oil is trival as the tip has the cross section easily capable of doing such work without harm. This work takes advantage of the same aspects of the knife which reduce the cutting ability :

In regards to the heavier edge configuration, this also shows its worth cutting harder materials, specifically metals as softer materials such as woods, plastics, etc. are easily cut at much lower angles. An example of this is given in the picture on the right where the XM-18 was used to cut a decoration to length which was wire wrapped.

Of course this is more effectively cut with a multi-tool with a wire cutter but putting it against a hard wood surface and just rocking the blade down hard also easily completes the cut. Using the knife to make such cuts is just an example of the one-tool or emergency / low frequency type use where the work is either unexpected or done so rarely that it isn't worth carrying a specific tool just to do it when the need arises.

As the edge angle is fairly high it easily does this type of work and similar wire/cable cutting without significant edge damage easily handling press cuts into various cables and wires. The main thing is to keep the material against a hard surface and just press/rock the blade through it to avoid twisting the edge while it is inside the metal. However given the high edge angle of the XM-18 even if it is cut fairly dynamically and a little sloppy there is usually little damage and just a little flattening at most.

Utility

Food

Using the XM-18 to clean a brace of rabbits in the most extreme manner possible :

There is no need to do any of this however this was just a check to see how the edge would hold up in such a case where almost no technique and a lot of brute force was used. There was no effect on the edge as expected expected given the high edge angle and thickness. This was repeated on the second rabbit, again the edge showed no reflection of light after the repeated bone contacts.

Field

Grip

Ergonomics : Keeping in mind that it is a three fingered grip the over all shape is well contoured and provided that it fits the general size of the hand holding it would be expected to be comfortable. This is the main downside of any extensive contouring or shaping as a hand which is too big or too small could put the fingers in the wrong spots.

The size of the handle does however raise a curious question as to why put a three fingered grip on a knife built obviously for very heavy work? Any attempt to use this knife for very heavy work does as shown in the picture at the right puts the end of the handle inside the hand and thus creates a high pressure point which gets uncomfortable rather quickly. This is only made worse when heavy gloves are used as then even a small hand would be much larger and would exceed the size of the handle.

It maybe that this knife is intended as a back up or emergency type knife where the full size version of the XM-18 or XM-24 can not be carried or used. Thus this knife is designed to be used for hard work (hence the thicker blade cross section and over built construction) but not for times when it is expected to have this be an extended task hence the smaller handle which is only a problem for that specific situation.

It does have some minor abrasion issues as noted in the above :

But the main limitation is just the size of the handle and the index finger choil both of which are fairly small unless you have rather small hands. The index finger choil is so small that it is really only useful in a grip with puts the tip far forward for precision work. As shown in the image at the right, if the choil is attempted to be used as an extension of a hammer grip for heavy cuts where maximum force is to be used and the leverage disadvantage is to be neutralized, then this puts the finger in a position to be easily cut by the blade.

Again with heavy gloves on this is only made worse and in that case even a forward grip can not be used without the gloves contacting the blade in the index finger choil.

Security : The G10 has a very aggressive texture but it is bi-directional meaning it is relatively smooth up and down but very aggressive side to side. It is thus very secure in resisting movement to take the knife out of the hand, but in general use the abrasion is rather low. Combined this with the fact that the handle in general is well shaped and providing it is of suitable size for the hand then security in general would be high.

Durability : The durability of the handle is extremely high given that it is made out of G10 and Titanium and is thus impervious to anything aside from environments which would be be extremely hazardous to the user.

Miscellaneous : the onset of winter made it quite obvious that the XM-18 was certainly not designed for use in such conditions as it was quite difficult to

the knife due to the size of the handle. Of course few knives are designed for working with heavy gloves but there are exceptions such as :

However this knife in particular really is at the limit that it is beyond saying it is designed for it, it is actually impractical to use in such conditions. But again this is the smallest of the XM folder line.

Edge Retention

Initially the edge retention was fairly low as within just a couple of weeks the edge was seriously degraded and also rolled/dented even cutting soft materials (plastics, cardboard, woods, etc.). However this was just due to the way it was sharpened from the maker which likely weakened the edge through power stropping/buffing.

Sharpening

After a couple of weeks of light use the XM-18 had no slicing aggression and a couple of areas were flattened/rolled. Thinking what about a Firefighter or EMT or other similar individual that this knives is marketed for who may not have optimal sharpening equipment or knowledge and may simply have one or two natural stones, this knife was sharpened with a less than ideal method.

Starting with a 3000 grit waterstone :

Again thinking of less than idea scenarios, deliberately the stone was switched to early and an 8000 grit stone was used to mirror polish the bevels. After 1000 passes per side :

Now of course proper technique and equipment would have been to initially apex the bevel on a 600 DMT stone and once it was fully apexed, only then move to finer grits. This was just a simple experiment to see how forgiving the steel (Duratech 20CV) would be to less than ideal methods/equipment and not surprising, given the very low grindability, it isn't very forgiving at all.

Steel

The steel is Duratech 20CV made by Carpenter, the same composition as m390 a steel made by Bohler. It is a curious steel to use for knives, a few points of reference :

If the last part is a bit surprising this is because S90V is optomized for MC carbide composition which gives the highest toughness at a given abrasive wear resistance. 20CV has a higher mix of carbides including the very large chromium carbide aggregates which are much softer than Vanadium carbides (MC type) and thus reduce toughness more while providing less abrasive wear resistance. These steels are designed for more non-knife related uses including chemical corrosion resistance and adhesive wear resistance (metal on metal).

As a general point, it makes little sense to me to use this steel on this knife, had this steel instead been CTS-BD1 or similar then :

And the cost to buy, machine/grind and heat treat the steel would all be lower.

Overview

Overview :

Comments and references

Comments can be emailed to Initial Impressions

  • Light Utility
  • Initial Sharpening
  • A brace of rabbits
  • 6 weeks out
  • Another two months of use

    and/or the YouTube Playlist.

    Most of the pictures in the above are in the PhotoBucket album.

    15/12/2012
    Last updated : 15/12/2012
    Originally written:
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