Phil Wilson Coyote Meadow Utility Hunter in CPM-10V


A shot :

coyote meadow

Specifications

The Coyote Meadow utility hunter was custom ordered in CPM-10V to offer maximum edge retention through high hardness and extreme wear resistance. The knife has a full distal taper to a slim point, the main full primary flat grind is ground an edge is less than 0.010" thick behind the bevel, ground at about 15 degrees per side. The blade is 4.5 inches long and about one inch wide. It is a modified Coyote Meadow utility hunter style differing from the standard model as its half an inch shorter and there is a hint of a trailing point. The Rockwell hardness is a uniform 62.5 HRC. The knife balances in the handle slightly behind the guard, which makes it very stable in hand.

The knife is very attractive and fit and finish is high on all aspects. The transition from flat stock to primary grind is made using a gradual taper, no abrupt angles to reduce blade strength. The sheath is made from very thick and rigid leather with a belt loop wide enough to swivel the knife forward at about 45 degrees. The leather is thick and stiff enough so that this swiveling does not occur unless intended. The presentation desert ironwood handle is attractive and ergonomic in hand, filling the grip nicely. It includes a thong hole for retention and safety.

The initial sharpness was very high, the edge was well formed, even, with no burr. Phil's method :

The blade you received was sharpened on a medium crystalon stone, polished on a white water stone and the wire taken off on a compound loaded leather strop. This provides a very aggressive cutting blade with some tooth but with polished flats for high bending strength. The next best is on a very fine DMT diamond stone and again finished on the strop.

UPDATE : Phil later raised the hardness due to extensive personal testing and feedback from users. He now runs CPM-10V up to 64/65 HRC.

A quick comparison to a couple of other blades

The custom was used alongside a few other blades for some miscellaneous utility work to get a feel for its abilities. It was readily obvious that the cutting ability and edge retention was very high due to the efficient geometry, steel type and heat treatment.

Cutting Ability

The modified Coyote Meadow utility hunter significantly out cut a Spyderco Calypso Jr. . Making vertical cuts through strips of unsupported 1/8" ridged cardboard, the custom 10V blade would keep cutting long past the the point where the Calypso Jr. would start to bend the cardboard. The cutting continued with both knives until the Calypso Jr. was significantly reduced at which point no significant blunting was seen on the 10V custom.

As a higher reference point for cutting ability and edge retention, the Coyote Meadow was compared to another custom in D2 made by Mel Sorg. The D2 custom was made from 3/32" stock, with a four inch flat ground blade uniformly heat treated to 62 RC. The edge bevel is about 0.015 inches thick and NIB had a convex grind which has been frequently sharpened with an 800 grit ceramic rod which induced a small secondary micro v-bevel on the edge.

Some specifications for the three knives :

Blade geometry specifications

Blade Steel Hardness Stock thickness Edge Thickness
HRC inches inches
Coyote Meadow CPM-10V 62/63 0.125 0.010
Calypso Jr. AUS-8A 57 0.125 0.021 - 0.019
Light utility hunter D2 62 0.094 0.021 - 0.015

woods

All three knives were used for about ten minutes whittling on some soft pine, each blade cut the wood well. They were also used to hack up well dried and seasoned very hard spruce limbs which were under half a centimeter thick. None of the knives chopped well as they are all very light, but each could make notches in the wood so it could readily be broken and they all could also readily slice through the wood making stakes. The Coyote Meadow has the overall most acute profile and was the better cutter of the three blades. In general the D2 utility hunter out cut the Calypso Jr. as the blade stock is significantly thinner, however on some materials like on thick woods, the D2 utility hunter is a little behind in straight push cuts because of the recurve.

miscellaneous vegetation

The blades also saw used on light flexible weeds and much more rigid almost wood-like stalks. Bundling the weeds together and pulling the knives through them, the two fixed blades were more efficient as they were longer, again the Coyote Meadow was slightly ahead of the utility hunter. The recurve of the utility hunter came into play when the blades were used to slice through the bundles of weeds [ref : sharpening recurves ].

The harder vegetation could not be sliced well, and on pure push cuts the relative performance was the same as it was on the woods. Overall it was quickly obvious that the fixed blades had a definite advantage for this type of work in that unlike the Calypso Jr, a lock blade folding knife from Spyderco. The fixed blades had no moving parts to get gummed up by plant matter, after the end of all this cutting, the Calypso Jr. was definitely not as smooth to open as material had gathered around the pivot and other areas. The fixed blades also had much superior handle ergonomics and security.

fabrics and clothing

The blades were cleaned and the pivot area on the Calypso Jr. relubricated. The blades were then used to cut up an old pair of sneakers. The first cuts were vertical down the back and straight down through the tongue. The Calypso Jr. could not make much advancement as it had been significantly dulled by the previous cutting. The two fixed blades easily went through the fabric. They were then used to cut right around the sides removing all the material and just leaving the rubber sole. The soles were then folded and cut in half, one with each knife. The very thin point of the Coyote Meadow very easily penetrated the thick rubber and glided down through it. Once the sole was 3/4 of the way cut through I released the sole and then just sliced right down through the cut. The recurve of the utility hunter gave it an advantage here. As these were used sneakers the sole contained a fair amount of grit and dirt.

in the kitchen

The cutting ability of the Coyote Meadow exceeds most kitchen knives due to the very thin cross section. However the guard made some tasks awkward and in general the utility hunter in D2 from Mel Sorg was a more functional kitchen knife especially working on a cutting board.

Edge Retention

As noted, after the wood and vegetation cutting the Calypso Jr. had been significantly blunted as its steel is significantly softer than fixed blades and the wear resistance is a lot lower. It was sharpened with fifteen strokes per side on a 600 grit DMT hone and stropped. It now had a fairly aggressive finish, it will shave but it a bit grabby. The utility hunter held up much better and was just slightly pebbled along one centimeter of the back of the recurve. This was not visible deformation, but could be felt by thumb nail. The edge was restored to full sharpness with a ceramic rod, twenty strokes per side. The Coyote Meadow was unaffected by the cutting, showing better edge retention and durability than the other two blades.

Handle Ergonomics

The fixed blades were in a different class than the folder which started to get uncomfortable quickly during the wood cutting. There were a few abrasion points around the clip, but the most significant one was that the inside faces of the Micarta are not rounded and this sharp edge would start to bite into the finger after a few minutes. The handles on both customs were comfortable and neither had any problems with security. The grip of Coyote Meadow was a little more comfortable because it is more rounded than the utility hunter. This would also make it less secure than the utility hunter but for the fact that it has a forward guard and dropped butt to prevent the knife from moving much in either direction.

Quantitative comparisons on edge retention and cutting ability

The Coyote Meadow in CPM-10V was also compared to a number of other blades to examine the cutting ability and edge retention in some details. Against some stainless steels and D2 :

The work should have used more material to better quantify the differences however however a clear constrast was seen, with the CPM-10V blade strongly leading. Compared to another stainless steel (VG-10) :

The Coyote Meadow in CPM-10V again fared very well. Later it was compared to a Battle Mistress and Basic #7 from Busse Combat :

The CPM-10V blade again stayed sharper the longest. Finally it was compared to a a Talonite blade, with the cutting comparison being very detailed :

The CPM-10V blade easily out-slices the Talonite knife and has much better edge retention in regards to resisting deformation and bite loss.

The knife was also compared to various other blades on used carpet, several times with each time the performance being very high : ref. It also did very well slicing cardboard with various edge profiles and finishes : ref.

Phil Wilson has also personally performed a lot of edge testing on rope, here is some of the information he has gathered with some background details :

Here is a series I recently ran on 3/4 inch rope. The cuts were all on the same 7 ft long piece of rope from the same roll. All cutting was done against an Alder wood block clamped to the bench. I judge the blade dull when it starts to slide at the bottom of the cut. At this point it will still cut paper but somewhat erratic. The blade will also skiv leather but with some force needed. I use a slicing motion, not a pushing shear motion to cut the rope. All 5 knives have the same blade length (5 inches), the same blade design (semi skinner),.125 stock, flat ground very thin,.015 behind the edge and all fabricated and heat treated by myself. All knives were tested twice. I do a sub zero in Ln2 as soon as the steel comes to room temp. Hardness values are done with my Wilson 3JR machine, calibrated with a Wilson certified test block (+/- 0.5 RC). Sharpening method was consistent on all blades.
Medium crystalon (silicon carbide) initial bevel, about 18 degrees 800 grit Japanese water stone to polish the flats on the edge strop on leather to remove the burr. Leather was initially lightly loaded with "green" buffing compound. This provides a brilliant toothed edge that will shave hair, but is not surgical. I consider it optimum for field work.
Edge retention comparisons on rope performed by Phil Wilson
Steel RC Number of cuts Average Ranking
CPM 10V 62 135-155145 +/- 14100
CPM 420V 60 130-135133 +/-   492 +/-   9
DAMASTEEL 60   90-105  98 +/- 1168 +/- 10
154 CM 60   80-105  93 +/- 1864 +/- 14
D-2 59   70-  85  78 +/- 1154 +/-   9
AISI 420 54   18-  25  22 +/-   515 +/-   4
The range is due to my "feel factor" and also the initial sharpening variations. The rack up is consistent with other tests I have done and also testing of my blades by other "hands".

UPDATE : Phil is now running CPM-420V (S90V) and CPM-10V harder, 62/63 and 64/65 HRC respectively and thus both have even better relative edge holding than in the above.

Edge durability and strength

The Coyote Meadow was used to stab into a pop can and pull up through it (the top had been cut off) at a decent speed. After five such cuts the edge was not effected, it still shaved and sliced paper easily. The knife was then pushed through some RS-232 cable which was then looped it and the blade pulled it through with a hard jerk. Again the edge was not damaged.

A heavier cable was then cut up. The cable had a core of fairly thick copper wire (one millimeter in diameter), with a wrapper of hard plastic core (two millimeter thick), and then surrounded by more copper wire. A few push cuts were made with the blade. The hard plastic shell was difficult to cut and it made the center copper wire slip and thus deform rather than cut smoothly. The blade was then pulled through a loop of the cable a couple of times. While the custom would still slice paper easily it now caught in one place on a push cut though the edge deformation was too small to be visible.

The knife was then used to cut strips off of a mild steel bar The pieces were small, maybe 0.5 of a centimeter in length and a dozen cuts were made in total. The edge was now blunted significantly and had numerous spots were the light reflecting due to impactions or rolls. These distortions were still not visible at arms length. Finally the blade was used as a chisel to cut the edge off of the Calypso Jr., the custom CPM-10V blade still did not chip out.

Sharpening particulars

After the cutting just described, the edge was restored with DMT benchstones, 25 strokes on each side with the x-coarse hone, and 25 per side with the fine. The knife was then given a light micro bevel with the fine ceramic rod. Comparing the edge to the usual sharpening session which was a light honing with the ceramic rod, the new edge felt much more aggressive. Discussing this with Phil, he pointed out that an optimal sharpening of 10V blade has to come from a hone which can cut the very hard Vanadium carbides.

To examine this in some detail the blade was used to cut up an old car mat. The custom was used to slice four foot lengths off the mat, and the the number of slices recorded as a measure of sharpness. The first few sections took about 21 +/- 2 slices . Some loss of aggression was felt and the knife would not shave any more. During the next eleven sections this performance was constant at about 26 +/- 1 slices. As a side note enough even though the blade was now dull (a finger could easily be ran along the edge) due to the very efficient geometry it could easily cut up wood, and after cleaning nicely prepared a sandwich.

To restore the edge a ceramic rod was used for a couple of passes per side. However while the edge would shave easily, it did not have much bite. The edge was then lightly honed with a 600 grit DMT eight inch bench stone, just five strokes per side, and again lightly micro-beveled the edge with the ceramic rod. The blade would again shave but had a much stronger bit which was evident as being much more aggressive in another try at the mat cutting.

A final comment about durability

As noted in the above the edge isn't fragile, and it takes some pretty serious cutting to do any direct damage, considering it intended scope of work as a light utility knife. The durability was in fact enhanced due to the very efficient blade geometry and ergonomic and secure grip which means that the minimal amount of force is necessary and it is used with the maximum amount of control. Of course this is a very focused blade, it would not hold up to significant prying or hammering. The corrosion resistance of CPM-10V is also fairly low on par with other similar tool steels.

Comments and references

Comments can be sent to : cliffstamp[REMOVE]@cutleryscience.com. Feedback can also be seen on the following ARCHIVED thread :

More information can be obtained on Phil's knives on his website : Seamount Knifeworks.

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


Last updated : 12 : 10 : 2005
  Mon Jul 24 14:43:13 NDT 2000
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