Initial impressions : Becker Patrol Machete

C

Cliff Stamp

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There are few high end blades in the 10+" class for use in brush work. There is no problem finding stamped out blades, but they suffer from three main problems. First of all the quality control is obviously not going to be great when you are buying them for $5-$10 each. Now of course it isn't critical if you get a bad blade if you are paying so little, but it is annoying to have to go through a few to get a solid one. Second is that they often come unfinished. The handle, which is often wooden, can be squarish and not well fit to the tang. This is solved with some work with a rasp, which also leaves the finish with a nice secure texture. The edge as well will come in a state that is only sharpened in the roughest sense of the word, and often needs rough shaping. However the most critical problem is that because they are stamped, and thus have no primary grind, they have the worst shape possible to cause heavy wedging, or binding in wood. They work well on soft vegetation as it can't exert any force on the sides of the blade, but chop one into a solid piece of wood and it stays there stuck. Ideally it would be nice to get a dual convex tapered blade, and you can find these if you go custom, but they are impossible to find production. The next best thing is a decent flat grind and this is where the Patrol Machete from Becker Knife and Tool steps in.

The obvious question that leaps out is why do you want something longer than 10" anyway? Can't a decent bowie of that size handle any chopping you need? Well yes in regards to raw chopping power, however that is usually not what longer bush blades are used for. Ideally the felling is actually done with a saw, and the blade is usually just used for lighter brush work and limbing out the fallen wood. The problem with most 10" class bowies is that since they are made out of 1/4" stock and quite blade heavy to make them excel in chopping in thick wood (Busse Battle Mistress for example), they don't perform at an optimal level for lighter work and generate too high a fatigue rate. Now of course you can use a slimmer bowie and solve both of these problems, and that is ideal except for one factor - reach. The length of the blade gives you three main advantages; clears a wider swath, protects your hand from abrasive vegetation, and reduces over-reaching. So the ideal larger bush blade takes something like the Battle Mistress, and basically makes it longer, slimmer and narrower. It should be thinner in cross section to provide a higher cutting ability, and more neutral balanced and/or lighter to reduce fatigue. Since it has a more acute cross section, it will bind more in chopping in thicker wood, but this isn't its primary function.

Additionally, it would be that would be nice to have is a distal taper. This means that the thickness of the blade is reduced as you run out towards the tip. Thus you have quite a thin section for light work, and a thicker section for heavier chopping where you want to reduce binding, as well as to maximize stiffness for prying chips out of the wood and overall be tougher. The actual blade curvature is also a point of interest. If the edge curvature is concave, then it will act to trap vegetation such as on the Woodsman's Pal. If the edge curvature is convex, like on an axe, it will excel at chopping heavy wood. A straight edge is a compromise between the two. You can achieve a similar effect to a concave edge if you angle the handle to the blade. For light brush work you obviously don't want the edge designed for heavy wood chopping so this means that the edge curvature should be concave. This does mean that you are giving up some thick wood chopping performance, but again this isn't the primary function. As a few final points; the steel should be very tough, at a decently high RC, wear resistance isn't a huge factor but is nice to have if you can get it, the handle should fill the hand well and allow both a firm grip and snap cuts without discomfort, a lanyard hole would be a very nice.

The Patrol Machete :

First off it comes in at about 490 g and balanced so as to be lighter in hand than the Battle Mistress. This is critical as this is the one element that is near impossible for the user to fix. It is also slimmer, made from 3/16" stock with a full height flat grind, of about 2.5 degrees, very acute, and the blade even has a slight distal taper. The edge has a convex curvature to trap vegetation, which also enhances the taper as the edge thins out towards the tip, exactly as desired. Getting specific, near the base of the blade the knife is about 0.040" thick behind the bevel and thins out to a very thin 0.018" near the tip. The steel is a low allow carbon grade, solid choice, at a decent RC to prevent excessive deformation or impaction. The handle is swelled for comfort and security and will allow heavy cuts as well as fast snap chops around the index finger and has a lanyard hole. The only stand out real problem is that the edge on mine is ground at ~19-20 degrees per side, this is optimized for hard woods, much harder than we have around here (pine, fir, spruce, birch) . I run my blades in this class from 10-15 degrees depending on steel, length and function.

Are there any actual problems? Well the NIB sharpness isn't impressive. It scores 190 +/- 23 g push cutting light thread and takes 1.2 +/- 0.1 cm to slice 1/4" poly under a 1000 g load. This is a little under about half as sharp as a well polished blade, and is far below shaving. It has the exact same problem as described with the C/U7, a buffed coarse ground edge. NIB sharpness is critial to some, of no importance to me. However I do find the handle to be a little squarish as it could have more rounded transitions, but it is a *lot* better than the handles on many other blades. I would also prefer a more aggressive texture on the grip. Personal preference obviously comes into play a lot with handle issues. The only real problem I can see has to do with the fact that the blade gets quite narrow near the base and does leave me with some durability concerns. I should be able to get some serious work in with it soon and see how it holds up. I bought a Tramontina bolo for a benchmark and have a number of quality custom level blades in that class to compare against as well.

Here is a shot alongside a Busse Battle Mistress and a Tramontina Bolo :

http://www.physics.mun.ca/~sstamp/images/camillus_bush_hog_bolo_bm.jpg

Here is a custom with a similar (but slightly heavier) intended design :

http://www.physics.mun.ca/~sstamp/images/parrell_parang_side.jpg

and some other large brush blades :

http://www.physics.mun.ca/~sstamp/images/al_bolo_bm_pab_ak_side.jpg

-Cliff
 
Cliff,
I am VERY interested in the results for this knife, as the PM will probably be my next knife purchase. I have a Livesay RTAK with a 14" blade of 3/16" 1095 and a full flat grind that I wanted to run it against, mostly to test out the usefullness of a recurve blade in this size knife and to compare the BK&T steel against properly heat treated 1095 (my RTAK has a differential heat with a 60RC edge, the heat treatment of Newt's 1095 is the best of any 1095 that I have seen it is hard enough not to roll during heavy use, and I have only experinced a small amount of localized chipping, mainly from inclusins in wood like small pebbles, etc....


Stay Sharp,
Chad
 
chad234 :

... the usefullness of a recurve blade in this size knife
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For a one blade only type of senario, I would definately pick a straight edge profile like the RCM/RTAK, as recurves like on the Patrol Machete do have problems in dedicated chopping on larger woods. However for small tasks like general brush clearing and limbing of felled wood, such blades excell in regards to smoothness of cut, raw power and edge durability, at a given profile. The latter point being critical as even small changes in cross section will swamp out the curvature effect. A very strong combination is thus something like the Patrol Machete and a quality pruning saw like those offered by Zeta, Felco and the like.

... the BK&T steel against properly heat treated 1095
Click to expand...

These are in theory very similar. However the Machax I used had problems with edge durability even though its edge was quite obtuse. I will be interested to see how this blade and the CU/7 hold up. You would expect a little more wear and corrosion resistance out of the BK&T steel is all. It would be near impossible to see any effects on wood chopping as there edge holding is determined by resistance to rolling and fracture, and in theory both of these steels should be near identical with the edge going to Newt's 1095 for the intrinsic greater durability of 1095, plus the fact that he has it differentially heat treated.


-Cliff
 
Sounds good Cliff, I'm interested to hear about the testing, especially as compared to the Busse BM.
 
The main blades it will be ran against are the Tramontina, your bolo/parang blade and my custom bush knife, as these are the same size. I'll be mainly looking at handling characteristics as well as raw cutting ability, durability and various issues like thick wood capability. It will be compared to other blades though and the BM is a solid benchmark for a 10" blade. Mine has been modifed from NIB though rather significantly, I'll mention that in the comparison. I was hoping to have done some work by now however it hasn't came above zero, and I'd like to get some soft work done with it before I move onto frozen hardwoods. If it hasn't thawed by next week I'll probably take it out anyway and just go really light to start off.

-Cliff
 
We finally got a window of decent weather so I spent some time in the woods yesterday, it was still below zero, but there was no wind, rain or sleet so you take what you can get. I had the Patrol Machete along with a Tramontina bolo, two custom forged large blades with convex grinds, a twenty inch Sirupati from HI, two axes, a couple of small folding saws and the CU/7. I went into an area that had been mainly cleared out and cut down and limbed out the remaining trees that were from two to four inches in diamater, nothing major. The trees were mainly dead, with only a few having actual living branches, the others just dead "hard ends", as we call them. In total it was just over a couple of dozen trees with all the blades.

Before I had at the trees, I first tried the Patrol Machete out on some grasses. It wasn't the sharpest NIB (at ~50%), but could slice most of the stiff grasses. The freshly sharpened Tramontina bolo did outperform it, showcasing the difference in sharpness. Based on my experience with the CU/7 it would only take a few minutes with some stones to get the Patrol machete at a fine shaving polish and then it would cut this material just as well as the Tramontina. Moving on to some actual light brush (small alders and the like), shows that this is basically the Patrol Machetes area of excellence as the curve "locks" the brush in where a straight blade can push it out of the way, so you want to use a draw stroke. However, again the sharpness difference was again noticed as compared to the Tramontina which also had a more acute edge so its shallow cutting ability was higher.

Anyway, I then moved onto some actual wood. I cut down one small tree with the Patrol Machete (PM). The tree was about 1.5" thick, soft wood, pine, but a little dead so it was close to a fresh piece of clear spruce in density. The PM took it down in a hit and limbed it out nicely. The blade curvature works well on small wood as it locks it in place, however the edge is too obtuse for decent cutting performance, personal preference comes into play here obviously, where your standards lie. The Tramontina was easily getting better pentration, actually able to sweep off limbs that the Patrol Machete had to chop into. The upper hump on the Tramontina also allows it to function very well as a mallet if you just beat the branches off with the spine, as they are dead, they crack easily. You can do the same thing with the Patrol Machete but it isn't as effective as it is thicker and doesn't have the hump.

I then moved on to bigger wood, still nothing major, about ~3.5", same type of wood, it was just more dried out and more dead. With the first chop I knew there were problems. The blade made a sharp ringing sound on impact which is never good as it should damp out vibration. The curvature also hampers chopping as you are hitting on a concave surface, the worst choice possible. Of course you can chop more towards the middle of the blade, but I was hampered in this case by other close vegetation, and besides the penetration and power is much less there. For bucking, this is the area I would use, different chopping technique there though. The blade also sticks significantly. It does better better than a flat machete like the Tramontina, but binds much more than say the Battle Mistress, which is just thicker. A nice convex grind would be optimal here, greater producion costs obviously. I was also working with the HI Sirupati at the same time and it was very fluid, no binding, and am now very interested in a Kobra.

Anyway, limbing out that tree was were the real problems set it. The penetration difference between the Patrol Machete and the Tramontina was now more obvious. Its simply a matter of edge angle, my PM is at about ~20 degrees per side, and the Tramontina is close to 10 with a light convex sweep to the last little bit of edge. Some work on a belt sander to grind the edge down and the Patrol Machete would match the performance of the Tramontina easily. However, while cutting through one of the larger limbs with the PM, I heard a snap and when I drew back the blade only about 2/3 of it was still together. The top portion had cracked off and landed in the snowback. There was also a half-moon piece missing from the edge and when I checked the cut I saw multiple fragments, which I dug out. The blade was rippled badly in that area as were the bits :

http://www.physics.mun.ca/~sstamp/images/patrol_machete_broken.jpg

Based on past experience with exactly this type of failure I know what happened. On a previous strike I had dented the edge. This left a part of the edge sticking out sideways. When this was impacted again it caused the bend to grow. If you keep this up, it will rip, or explode through the steel causing multiple fractures depending on the toughness. I have ripped 5160 blades for example in this manner. If you catch it in time you can try to hammer it back into place (carefully), or grind it out. I checked the wood for a nail or any other inclusion, but it was clear. This could not have been the case anyway as it would have scratched the coating and impacted the edge directly, neither was the case. I knew from past experience and basic principles how this fault is caused anyway, however it never hurts to be sure. I finished off that tree with the Tramontina.

In retrospect I should have kept the top of the blade, where is it much thinner just for fine work and concentrated on limbing with the region near the handle where the edge is much thicker. However when the limbs are very close together, this is difficult to do, as usually you just sweep them off, working inwards, and this means you are working with the tip. To have a more complete picture I should have also spent more time working with the blade on softer woods especially comparing it to the Tramontina with the edge ground down to a similar angle. It would have been interesting to see just how low it had to get before the cutting ability was the same. Obviously it could be more obtuse because the edge was thinner.

If it seems odd that the Tramontina was more durable then you have to consider a few main factors. First off since its cutting ability was much higher, the impact the blade "saw" was much lower under a given load because it was spread out over a much longer time. As well because the blade was straight, and not curved, again the pressure of the impact was lower, under a given load. In addition, because of the greater cutting ability, I was also to use it with less force and achieve the same results, this just amplifies the above two effects. Finally, even though the Tramonina is of thinner stock, it has no primary grind and thus is pretty much 1/8 of an inch right behind the edge and thus as you go back from the edge, the Tramontina gets thicker much faster than the Patrol Machete, and thus is much stronger. The Tramontina however would for example take much more edge damage if both blades were chopped into inclusions, under the same load.

I'll have a post up on the Tramontina in awhile as I want to do some work comparing it to a few other blades, including a custom that I need to do some edge work on, as right now its too obtuse, ~20 degrees per side (the custom, not the Tramontina). I want to get it to at least 15, and hopefully much closer to 10. It forged 5160 so it should go pretty far.

-Cliff
 
That's unfortunate. My experience with the Patrol Machete has been very positive, with the only damage coming from impacts with rocks near the tip.
 
WOW!!!! Now these are suprising results!!! Luckily BK&T knives come with a great warranty, I have heard nothing but great things about Will Fennell, I'm sure that it will be replaced......
What kind of grip security did you experience???? I think the Becker handle design is great in that it is hand filling (which I find prevents blisters, and allows for better shock absorbtion) and seems to offer excellent "mechanical" security, my concern is that the handle material seems quite slick. The glass filled polymer seems very durable however, much more so than I expected. While It could be covered with grip tape, that is not an option that I prefer....

Looking at the metal at the point of failure is there any indication of defect in material or heat treat? How uniform is the texture of the metal, are there any obvious inconsistent areas?

How did the machete size blades compare to past work you have done with the Battle Mistress?

Thanks,
Chad
 
Chad :

[grip security]

I think the Becker handle design is great in that it is hand filling (which I find prevents blisters, and allows for better shock absorbtion) and seems to offer excellent "mechanical" security
Click to expand...

I would agree here, there are too many flat and small handles, it is very nice to see a shaped grip of a decent size. McClung also has a very nice grip on his larger models like the TUSK. My main problems with the Becker grip are the holes which are abrasive to my fingers (which can be filled in), and that the end-hook is on to sharp an angle, it should be taper at a lower slope to enhance snap driving. You want some resistance to torque off of, but nothing that sudden that it gives a sharp impact. When I had that custom made in the above I also flared out the end-hook to also reduce the pressure. As a side effect of the flaring, I can use it just by the end knob for maximum reach and speed. In hindsight I should have got a laynard hole made in the grip, I'll fix that shortly.

... my concern is that the handle material seems quite slick.
Click to expand...

Yes, the grip doesn't have the texture that I would want, it is too slippery. Right now that isn't much of a factor as you are too cold to sweat and the sap isn't flowing. However in late summer, rotting sap and sweat make a devil of a grip "juice" to work with. I just "checkered" the grip on my Machax with the file on my SAK, using it like a scraper.

The glass filled polymer seems very durable however, much more so than I expected.
Click to expand...

Yes, you basically have to hit it with a hammer to break it. It is not in the same league as Micarta (mainly because it is hollow), but nothing short of hammering on or with it, is going to cause a problem.

Looking at the metal at the point of failure is there any indication of defect in material or heat treat? How uniform is the texture of the metal, are there any obvious inconsistent areas?
Click to expand...

The steel is uniform, nothing odd, and of very fine grain which you would expect at this hardness and alloy content.

How did the machete size blades compare to past work you have done with the Battle Mistress?
Click to expand...

While the BM is a fine 10" class blade, I greatly prefer longer blades for brush work mainly for reach issues. About 14" is as long as I would go as then they become too difficult to use for knife work. However a longer heavier machete is a wonderful thing to have for limbing just like a light axe. The heavy duty 18" Barteaux makes a great heavy limbing blade. I would want an additional smaller knife however alongside such a knife. With the BM it can handle all of it, just not as well as the task-specific blades.

As a direct comparison, since the BM come with more acute edges NIB they would out-cut the PM I had, especially since it was rather dull, but even after sharpening, the edge angle would have been the dominant factor. Assuming the edge had been thinned out, the PM would then get better raw penetration, but I don't think it would be productive on heavy wood cutting because the blade would be sinking in pasts its width and the wood would actually bind in over the top. It would readily out-cut it on light vegetation and limbing though.

Binding of course strongly depends on the nature of the wood and the technique used. On really soft woods like fresh, clear, pine, binding isn't a problem, even for flat machetes. As well the energy of the impacts is also a critical factor. The lighter your swing, the less you will be concerned about wedging.

In regards to the edge bending/rippling, this doesn't surprise me, given the geometry. I have a custom 10" bush knife coming from Phil Wilson, the optimum geometry he felt was practical was 0.020" behind the edge, on 1/4" CPM-3V with at 58/59 RC. In the part of the PM that rippled it was actually thinner than this at ~0.018. Now that might not sound like much, but it is actually ~25% weaker, couple this with the difference in edge growth due to the blade stock (~56%), and it under-cuts that design by quite a lot. Phil hasn't made that judgment firm yet either, he has some prototypes to evaluate.

As for the breaking, when you get steels up that hard and uniformly hardened, there are very few than can take a rip without propagating it quickly through the steel. Which is why in general, I'd drop the RC a little for a safe-guard, or better yet go with a different steel like L6, edge retention is not nearly as critical as durability on large hackers. There were probably multiple dents which each spawned micro-rips. From this experience, if I was working with one again, I would just be much lighter with tip work on small hard branches and be very careful on heavy-growth so as to avoid glances, which is what causes the dents, as they induce lateral edge loads.

Besides just swinging lighter, if you have more skill than I have, you would not have seen the problem I did. However, with heavy in-growth, glances are almost impossible to avoid, uless of course you are very careful and slow down greatly and basically pick the brush apart carefully piece by piece. The wood is also the other factor, you won't get such problems on softer wood, nor if the wood is larger. The latter might seem odd to some, but you could easily take the same PM I had and chop through a telephone pole with no durablity problems. The larger the wood, the lower the impulses of the impacts.

The Tramontina is proving to be a very nice light brush knife. I had to do a lot of rasping on the handle, to get it functional, and still need to cut the end-hook. The biggest problem with it so far is the flexing, it bends during chopping, even when felling small trees. This does reduce performance, but the raw ability is enough so that overall it is still very strong. I suspect though that it isn't going to be that functional on thicker harder woods as it will bind and doesn't have the stiffness for chip breaking. I'll see how that goes when I get to do some bucking.

-Cliff
 
This is mainly to address the comments that Chad made about his experience with a Tramontian bolo as compared to some comments I made both in this thread and in another :

http://www.bladeforums.com/forums/showthread.php?s=&threadid=196116

I took the bolo out yesterday along with the GB Wildlife hatchet and used both to take down 8 small trees each from 2 to 4 inches in diameter. I was looking at raw cutting ability, ease of use and fatigue issues. It was soon obvious that on the small trees the bolo could cut them well, little fatigue and limbed them out easily. It was just as obvious that it struggled with 4 inch hardwood trees as it would bind heavily and had no ability to pry chips out as the blade didn't have the stiffness. Better performance was achieved by working very close to the handle, but then you have a lot of blade getting in the way as its out past the tree which forces you to work higher off the ground as well as have more area cleared out. The bolo and a small saw are a very strong combination.

Nothing surprising here, the size of tree that is comfortable to chop down of course depends on its nature. Softer fresh wood of four inches thick would be very easy to handle as compared to the harder woods I was chopping and thus the bolo would have no had problems until the wood got much larger. On the positive, the modification that I made to the handle, cutting back the angle on the end-hook was perfect and allowed heavy chopping to be performed without any excessive impacts to my pinky, and without any loss of security. On the negative, the edge got dented up quite excessively during both the felling and the limbing. I also gave a car door a couple of light taps and the edge just folded in, with little or no resistance.

The other day that I used it, the wood was simply much softer, still a lot harder than fresh, but yesterdays wood was like a rock. The branches were breaking often the edges were that jagged that when I got a little sloppy one of them contacted the side of my hand and easily tore out a piece of flesh. In any case, the dents were mainly about 1 mm long and less than 0.5 mm deep, however one large one was about one cm long and 1 mm deep. The couple of car door hits left large impacts and the steel was actually directly compacted, the wood of course can't do this, it just bends the steel to the side. The angle of the edge in the bend area was from 10 - 12 degrees per side. This geometry is possible on a steel that is very durable at a high hardness (~60 RC), but it is too weak on this steel.

So I take out a file and grind out all the damage putting a small secondary bevel along the edge that is about 2 mm wide. I then polish it with some waterstones and CrO to a fine shaving finish, which has a slight roll, but that is difficult to remove on this soft a metal. Anyway, the bevel angle is just a little steeper, it ranges from 13 - 15 degrees, so it is just a 3 degree increase, but this will actually give about a 65% increase in strength to the edge. I'll try this out, starting on some softer wood and working up to the harder stuff and seeing how careful I have to be to keep the edge clean. If I have to go much more obtuse with the edge I'll just write the blade off as by then the light cutting ability will be too low. But I suspect that it should be fairly durability at this level, and a few degrees more should allow even sloppy hacking with only minor problems.

The PM is going back to Camillus, it will take about 2-3 weeks to get there, so expect an update on it in about a month or so.

-Cliff
 
The Patrol Machete replacement arrived last Thursday, I picked it up Friday. The NIB sharpness was higher than the last one. It cut the light thread taking from 80 to 160 g of force. Showing a range of sharpness which was at best equal to any production or factory knife I have seen. It also scored very well on the poly, taking one to three cm to cut through. Not doing as well here as on the thread, showing a light lack of aggression. The blade shaved easily, and would cut light thread with no problems.

I spent Friday evening, all Saturday and Sunday, and in the evening on Monday and Tuesday, in the woods with the blade (and others) about 20 hours total. The tip was used for bucking and felling on the softer woods like Pine and some of the harder woods like Spruce that that had rotted, you get 3-4" of penetration just with a wrist snap, they are that dead soft. There was also some limbing done with the the base of the blade, and some chopping in that region as well.

On Sunday, before sharpening, out of curiosity I tried the can cut that the ABS guys do (vertical cut through a pop can), and the Patrol Machete suffered no damage after eight cans. It was hard to do the cuts though as the recurve kept throwing the can, and the blade was fairly dull at this point. A later light sharpening (to check edge for hollows - there were none) proved that there was no damage at all, as the blade showed no rough spots slicing up some paper. I don't know what this actually means though in regards to durability, as I have not done the can cuts on many blades.

Anyway, the knife has many positive attributes, and I would prefer it over the common 10" blades like the Battle Mistress for example in a lot of situations, mainly soft wood and brush. It gives more reach, and the hooking action provides more cutting ability and less batting around on springy vegetation. It has the most optimal edge profile I have seen on a machete so far, in regards to the modifications I would make. I would just drop the edge profile down a few degrees to 10-12 per side, which would be optimal for thick wood, and light brush. The tip does bind excessively when chopping on soft woods, but you would expect that given the thin grind, it works very well cutting cleanly through the leafy vegetation.

The total number of chops performed over the five days of work, was in the range of 2000-3000. I was swapping it out constantly to check its performance against several other large blades, mainly a Jungle Knife from Martindale, a Tramontina Bolo and a custom RTAK from Newt Livesay. It could hold its own against them in regards to chopping and limbing, and all of them I had heavily edge modified. The only real problem was the tendency to glance on thick woods, which is just in the nature of concave edge face. It didn't have the ability to pry out wood, which I verified by going to ~35 degrees a few times just to check stiffness, only wrist leverage used. No splitting was done either, the blade received no heavy impacts (all reserved for later).

However, late on Tuesday evening, I was working my way up a 4-5" piece of soft wood, from base to tip, clearing the live limbs (no dead wood, no ingrown branches), when my attention slipped and I used the Patrol Machete near the tip to chop into a limb. I was using a standard method, angle cut about 1" up from base, then cut near base to clean out the chip, repeat as necessary, lop off when just a little remains. Up until then I had been making sure to work near the base of the blade where it is thicker when limbing. I heard a snap, several large pieces of the blade had broken away, one piece remained lodged in the wood. This is the same thing that happened last time. On the previous occasion, I saw more edge damage, but I was using a fuller swing and thus that would be expected. The wood and blade bit :

http://www.physics.mun.ca/~sstamp/images/pm_edge_wood.jpg

I then wrist snapped the blade off a log on the flats lightly to check for crack propagation. On the third hit, the entire top cracked off with a loud PING. These were light hits, I could take them to the back of my hand with no problem (tested it, a little sting, and left the imprint of my cotton glove on my skin). I then stuck the blade in a stump and flexed it until it broke as I was curious about the flexibility. It bent easily, being 3/16" thick with full flat grinds and very narrow. I just stood to the side and pulled on it with one hand.

It went very close to 90 degrees, 80+ easily, which was impressive. However when it broke, it did so violently. It broke again at the top where it was in the wood (the triangular piece that is missing), and exploded in the middle of the bend, as you can by the following picture, losing large pieces of the blade. The breaks that happened in the bend are very irregular, not clean.

http://www.physics.mun.ca/~sstamp/images/pm-replacement_broken.jpg

To clarify, here is how I would rank the chores for cutting woody brush, from hardest to easiest :

1) sweeping cuts through ingrown small dead branches
2) sweeping cuts through individual small dead branches
3) clean angle cuts through individual small dead branches
4) sweeping cuts through live ingrown small branches
5) sweeping cuts through live individual small branches
6) clean angle cuts through individual small live branches
7) clean angle cuts through thick wood (bucking or felling)

Working from base to tip when limbing along the trunk is also easier that tip to base, which should be avoided if at all possible. I am still working on refining the angle necessary for each stage, some are much closer than others (three and four are near identical for example). I would estimate the total difference in durability from top to bottom is easily a factor of five in edge angle required. The Patrol Machete broke at between five and six, it wasn't a completely clean angled cut, but it wasn't a dedicated hard sweep either. I have already mailed Will, and the blade will be going back to Camillus if they want to have a look at it.

-Cliff
 
Cliff, What did Camillus say about the broken blade? Did you get another one? What do you think about the performance of this alloy in a chopping blade?
 
Jeff, I discussed the performance with Will on the phone, you can drop him an email or make a post on the Camillus form for a public responce. In short, no I won't be looking at another PM, however I will be looking at one of the new #9's. In regards to the steel, it is not what I would want for a large chopper, not because it simply had problems, but because of their nature. For example I have been using Martindale machetes of similar edge profiles (0.020-0.030", 10-15 degrees per side) and they also will take damage on similar tasks, but they will just ripple and not be prone to brittle failure.

To clarify, the onset of the damage is as I would expect given the geometry and usage based on what I have seen with large blades for that type of task. Limbing is very hard on a blade due to the high concentration of force. Specifically, the edge on the PM is only 0.018-0.022" at its thinnest (for the ones I had), and due to the full flat grind of only a few degrees, it thickens slowly above the edge. For reference, Phil Wilson reasoned that 0.020" would be a lower limit on a 10" long, 1/4" blade of CPM-3V. The Patrol Machete is longer (and thus faster at a given swing), with a thinner edge and primary grind (due to the thinner stock).

I would reason that if the edge angle was made more acute it would raise the durablity by increasing the impact time, and thus spreading out the force. The edge angle is too obtuse (~18 degrees per side) for the type of work the blade works well on. Lowering the edge angle would also directly lower the probability of lateral loads as it would reduce glances. I had intended to look at this with the second one applying a wider convex edge. Now this edge alteration does make the very edge more prone to rippling, but it is not damage to the edge bevel which is a primary concern but damage which extends into the primary grind.

-Cliff
 
I've had a patrol machete for about a year now,and have used it extensively to clear brush and small trees.I wasn't happy with the edge as delivered either so I put a convex edge on with a slack belt after using it a bit.I have had no problems with chipping or cracking of the blade,and have seen excellent edgeholding for a knife of this type and the use it's recieved,particularly since I reprofiled and polished it.I've chopped through live alders and firs up to 5" in diameter quickly and easily and it is the ultimate blackberry chopper,I've also used it with a baton to split up some firewood .I wouldn't use it to chop through dead hardwood though,it simply isn't a good choice for that task.Unless you live in a jungle environment the PM is probably not a good choice for a "one knife does it all" scenario,and unlike a battle mistress it isn't designed to be unbreakable,but rather to do a particular job very well,that job being cutting live wood and brush up to about 3".I believe in matching the tool to the job and the PM does what I need it to do better than any other tool I have with the possible exception of my stihl brushcutter.I really like the handles and the coating is holding up well and hasn't yet been breached after many hours of use.The PM lets me continue to work for a long time without fatigue or blisters,something I've come to appreciate after using a khukuri for an afternoon(also a great blade,but not ideal for blackberries)
 
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