Machete Edge Holding

M

me2

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Oct 11, 2003
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I started this in the wrong forum, so I thought I'd continue it here.

I started with a Cold Steel panga machete (CSPM) chopping a 4x4. It was freshly sharpened and after going throught the 4x4, it would still shave my arm. It was sharpened on my trusty HF 1x30 belt sander with a worn 180 grit belt followed by a leather belt w/ white compound. I must say I was quite surprised it held it's edge through the chopping. I may be lowering the bevel from 15 to 10 just to see what will happen. If that goes well, 5 degrees per side, here I come.

I finished a little while ago cleaning up some limbs in the back yard. I trimmed them off one of the trees, then cut them into managable sizes using my new Cold Steel Barong Machete (CSBM). The sizes ranged from small branches up to 4" in diameter. After an afternoon of work, the CSBM still shaved along its entire length. It was sharpened at ~20 deg/side in the same manner as the CSPM above. I was very careful to not hit the ground with it, and it kept it's edge well. I'll be lowering it to 15/side in the future. After all this work, about 20 strokes on the Sharpmaker brought it back to trimming hair off the back of my head well above the skin.

This brings up 2 questions. First, where did the idea come from that a very sharp edge on a machete won't last? Second, what are people doing to have their knives and choppers dull quickly? The last question comes after this chopping session and some work cutting cardboard with a RAT-1 and Byrd Cara Cara. During all these cutting sessions, the edges lasted and lasted.

As soon as I get some more wood, I want to try my Cold Steel Kukri machete. It is freshly sharpened and I want to see how it will do compared to the other 2.
 
My machete edges are sharpened the same way with a 1x30 belt sander using several belts up to 600 grit. I don't know what angle it is but it is a very wide and shallow convex and my edges hold up extremely well. This has been true for all of my machetes including Ontarios, Tramontinas, Cornetas, etc. I have been sharpening them like this for many , many, years using files before I had the belt sander for about the last 10 years. I use them a lot in the swamps of the Big Cypress and I can't remember the last time an edge rippled or chipped. The thin edges are very easily brought back just using a piece of cardboard and sandpaper and/or a small round diamond file which I carry with me.
 
I've had machetes that basically had no flex in them that would ripple or fold under this kind of use. They were so soft that they would almost bend immediately if flexed sideways. Of course these were only $2. My Cold Steel machetes have been the best I've tried. I have an old military surplus machete that was my grandmothers I'll have to try this treatment on and see what happens. Its not been sharpened in my lifetime (35 years) that I'm aware of, so it will be interesting to see how it compares to more recently made versions. If I can get the handles off without breaking anything, I'll try to replace them with something other than thin plastic, though I have made that plan for about 8 knives now and haven't finished one yet.

How wide are your bevels on what spine thickness? I really want to lower the panga to 5 degrees per side. I built a box to hold my HF sander running horizontal and just block up one side to get my angles. Then I use a picture level with a magnet to keep the blade flat. When doing it free hand, I always hold a lower angle than I think. This way takes some practice, but it keeps things more even than the factory grinds/edges. I was pleasantly surprised to see the barong machete came with a factory bevel of about 15 degrees, so the 20 degree edge only took about 3 passes per side on a 120 grit belt, followed by the same on a worn 180. My favorite belts were the Klingspore 320 grits, but there is no Klingspore store near me now, so I get the finest I can (180) from the local Fastenal store.

I definately rolled, and perhaps rolled to the point of chipping, my kukri machete. Several accidental power strokes on a buried brick cutting roots wrecked whatever edge was left. Thought it was one brick. Turns out, the previous owners of the house had them all the way down the flower bed border. Found #s 2-4 with the machete:grumpy:
 
My Tramontinas and Cornetas are very thin machetes which I think are 1/16" but for sure no more than 3/32" just by eyeballing in comparison to my Ontario which is 1/8". The bevels I put on are approximately 7/16 to 1/2" high and fully convexed on a slack belt. I usually put the edge on by handholding the machete as far parallel to the belt as I can without taking any skin off my fingers.

The edges are very thin and will cut you if you look at them wrong. You have to be very careful when swinging them around and always try to swing away from the body. One wrong swing and you could do some serious bodily damage on a pass through. They will cut through 1" and sometimes up to 2" thick green wood almost like it wasn't there when you get the correct angle of cut. I use them a lot when clearing shooting lanes in some of the more highly brushy areas I hunt just south of Lake Okeechobee or just scouting through the Big Cypress swamp before deer season.

I hate a thick machete for this type of work and the woods I typically hang out in. Thin is in for me.

I order my Klingspor sharpening belts for my HK 1x30 from Pop's Knife supplies:
http://popsupply.bizhosting.com/kingspor_1_inch_belts.html
 
I'll have to lower the angle on the CSPM to match the others. I can tell a difference in the way it cuts when compared to the CSKM, though this could be the slightly longer blade and more forward balance of the CSKM. Also, the CSBM seems to have a different sweet spot closer to the handle, which will take some getting used to. Thickness is in the 3/32" range for the CSKM and the CSBM, while the CSPM is about 1/16". This one is apparently intended for lighter brush clearing, so I think the lower angle may work fine for it, and if not, at 5 deg/side, it would be easy to use stones or the belt sander to make a secondary edge bevel.

So as low as you take the edges, they have never buckled or completely rolled on wood? Do you use them exclusively on green wood, or do you get a few practice shots on some dried lumber before setting out with them? How does the extra weight of a 1/8" spine feel? Too heavy, but needed on some thicker cuts? I've wanted to try to make my own machete for a while, and was looking at either 1/16" A2, or 1/8" S7 steel. I'd prefer the S7 steel wise, but don't know if the 1/8" stock would be too heavy.
 
Make your machete. You will be happy to experiment and have fun at the very least. I am making my own using 3V and CPM M4.
 
me2 said:
As soon as I get some more wood, I want to try my Cold Steel Kukri machete. It is freshly sharpened and I want to see how it will do compared to the other 2.
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is this the cheapo $14 one? I'm very interested to see how you like it.I have the same belt sander and have convexed my CS cheapo and it holds an edge even slamming into the ground from time and again.. its probably one of the best machete steels I've used, surprisingly though a lot of people bash it.. and was even considering a bad batch of steel got cut loose from africa.. Mine has been good to me over the last year..

your sharpening method is whats made your experience IMO.. I've got several cheaper machetes that have out performed my HI's (which in my newly formed opinion isn't saying much)..

I bought a Marbles Bolo when they came out and was very disappointed.. it chipped, rolled and simply was shameful compared to my CS Khuk, that is until I convexed that bad boy.. its a chopper now..
 
Me2,
I mostly use my machetes on green wood and dry wood on occassion but never anything much over 2 inches thick. Just haven't had a need to. I really can't remember any major deformations occuring or maybe I am just not that observant. I know I always touch up the edge after returning home on a ceramic stick or fine diamond round file just out of habit every time I have used it for more than a few minutes. A few strokes on the ceramic sticks always brings the edge back to real sharp.

I would never try to baton with it as many on these forums seem have an obsession with. As far as the 1/8 to 1/16 comparison I really prefer the 1/16 because it just swings so much easier and is less fatiguing on the arm and shoulder. What I have found with these super sharp edges is that they cut through the wood so easily that a fairly light swing cuts all the way through minimizing the risk to your body parts and affording much more control.
 
In general I'm not a fan of recurve blades but the CSKM is one of a few exceptions. It has done quite well in my yard work evaluation. I really like the barong machete (CSBM) too, and I've been using Panga styles for about20 years. I've given my opinion on the geometry of the HI kukris and kukris in general in your other thread. I really need to try one to be sure I'm right, but if the pictures don't decieve, they seem to beat the wood into submission rather than cut it. Maybe they work better on Nepal's local hardwoods, where their mass still won't be enough to get the blade much deeper than the edge bevel into the wood on a perpendicular cut.

I don't really side with the "convexing fixes everything" school of thought, but on chopping blades it minimizes binding and results in a slightly stronger edge when properly done. On your Marbles machete, I'd hazard a guess that you removed some damaged/overheated steel and possibly raised the edge angle a little, which explains your increased performance. Just remember, small increases in thickness behind your edge, or anywhere for that matter, will result in very large increases in strength w/r to bending of the edge. For instance, going from 1/16" spine to 1/8" spine results in a blade that is 8 times stiffer than the original thickness. The numbers aren't the same magnitude for edges, but the general concept remains the same. The same concept works in reverse as well, meaning lowering thickness drops the stiffness very quickly. Extreme thinning of an edge should be carefully thought out and done with caution.

Which brings me to Alex's machetes. After running some numbers, your edge angles are in the 5-8 degree/side range, very thin for chopping, unless you've read Leonard Lee's book on sharpening (everyone should once). For felling axes used in green wood, he recommends angles in the 7-10 degree/side range, surprisingly thin by most people's standards, even for knives, let alone axes. If you are so inclined, I wouldn't think batoning with a 1/8" thick machete would do any damage to it, but you could buckle or twist the 1/16" ones pretty easily. I'm completely conviced the notion that sharp edges are delicate and should not be used on chopping tools is a myth. It's counter intuitive to be sure, but after seeing how much easier it is to cut and how long the edges can actually last, I can reach no other conclusion. Just as with my cardboard cutting tests, the amount of cutting that could be done before the edge would stop slicing paper is immense. Maybe this weekend I could try that on the scrap I've got left over in my yard. Even if the edge didnt last, the amount of control and ease of use might be worth the extra sharpening.
 
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me2 said:
After running some numbers, your edge angles are in the 5-8 degree/side range, very thin for chopping, unless you've read Leonard Lee's book on sharpening (everyone should once).
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me2, what book is that and what other good sources on sharpening would you recommend? I confess that I'm almost sharpening illiterate. I can get my knives arm-shaving sharp, but I still have a lot to learn on the subject.
 
Leonard Lee's The Complete Guide to Sharpening. See his store's website at www.leevalleytools.com. His recommendations on bevel angle are quite unconventional in some cases, but he spend a childhood chopping wood in Canada, and must know more about axes than I do.
 
Preacher Man said:
me2, what book is that and what other good sources on sharpening would you recommend? I confess that I'm almost sharpening illiterate. I can get my knives arm-shaving sharp, but I still have a lot to learn on the subject.
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I'm with ya on that one for sure.. there for a while I thought I was really getting good, but then you start mixing in different blades/lengths/geometrys, and a lot of what i thought i knew goes out the window.
 
I can think of only one or two times I've needed to resharpen a machete in the field. As long as you aren't torquing the blade through the cut or banging it into rocks your edge should last plenty long. :)
 
Yep. I'm just amazed that such inexpensive choppers can hold such a fine edge for so long. it's completely against the belief that super sharp edges are delicate and not worth the effort for this type of blade.

On that note, I spent another hour or so chopping all the wood I cut from the tree into pieces no larger than 1' long, even up to the 4" diameter setions. The edge will still cut a few hairs off my arm, and will slice paper easily, even into little curly confetti. I'm almost out of natural wood, so next I'll move to a scrap 2x4 I got and then finish off the 4x4. If it still slices paper after that, I'm done. If it still shaves hair at all after that, I'm calling the "super sharp is delicate" myth officially busted. Sorry, new season started.
 
I've been using machetes for 35 years around the farm. My dad, for whatever reason, was a machete guy. Can't recall him ever swinging an ax and if the machete wouldn't do it, he used a chainsaw. Of course wood-splitting, well that's what I'm here for right :thumbup:

Anyway. I have never bothered to worry much about the edge on my machetes (Collins Legitimus). We always just roughed on an edge with a file and that'd keep us going for a a very long time. Never once touched up the edge until the thing dulled up something fierce.

Collins are thin and springy so that helps...they cut pretty well even if dulled. We routinely chopped against the ground. Never slowed us down.

Interesting how people do it differently.
 
It's all in what your used to using. I used a filed edge for a decade and a half. It took down trees, cut grass, cut down corn after picking, kept the trails clear and fought back the kudzu. However, as long as I can get an edge this sharp in less time than it takes to file one, I see no reason to go back. If for some reason I can't use my belt sander, I would start with a filed edge again. I'm sure I'd polish it with hand stones a few times to see if the effort was worth it.

I've heard lots of people say the fine edge will dull very quickly and it's not worth the effort. I will say they are wrong on both counts. It's worth it if for nothing else than the ease of touch up. I had the edge down to about as dull as it is now after my afternoon of yard clearing. I brought it back to clipping hair off the back of my head with about 20 strokes on the Sharpmaker.

Hitting the ground isnt really that bad, and in real use its almost unavoidable. I've hit the ground a few times and the edge still shaves hair off my arm. Hitting a buried rock is another thing. As long as the edge doesn't roll too much or a piece get taken out, it's pretty easy to fix. A polished edge is stronger for chopping and mitigates this kind of damage to some degree.
 
Another update. The barong machete is still sharp enough to cut about 5" off the end of a free hanging rope. No sharpening or touch ups have been done to the edge.

The kukri machete was freshly sharpened and cut the free hanging rope. Then it went through a 2x4 twice and still shaved. After some more work, and a few more cuts through the rope, the edge rolled a little in a section about an inch long. I'll probably fix it with the Sharpmaker rather than do a full resharpening. There was some remaining damage from the brick impacts that I didn't take time to remove during the resharpening, so the rolling may be because of that. The area of impact with the 2x4 was about 3 inches long.
 
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