Need help with sharpening Cold Steel's 1055 carbon steel.

L

Lotus Leaf

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Jul 18, 2011
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Ok, so I have Cold Steel's G.I. Tanto along with some of their machetes (Kukri, Gladius, Katana, and 2012 Kopis). All of these are made with 1055 carbon steel. Since they came with somewhat miserable edges, I wanted to improve them, as I do with all my blades. Since I'm more of a collector than a user, I aimed to get them hair-shaving sharp, as Cold Steel describes they can be.

I've gone through a few methods. I tried the Spyderco Sharpmaker, but it didn't seem to remove metal quickly enough and proved to be awkward when trying to sharpen my machetes. I tried using my DMT diamond benchstones (coarse, fine, and extra fine). I tried sandpaper for my machetes as well, progressing from 80 grit dry sandpaper, 320 grit wet or dry, 1000 grit wet or dry, 1500 grit wet or dry, and 2000 grit wet or dry. In every case, it seemed like the tiny burrs created from using the rougher grits proved more useful at roughly draw-cutting paper than an edge with burrs removed at the finer grits. For example, after polishing the inner curve of the Kopis machete on 1000+ grit sandpaper(s), the inner curve lost the ability to draw cut paper.

So in my experience, 1055 carbon steel won't take a great edge. At least not like Cold Steel's SK5 carbon steel on the Leatherneck, easily takes a razor edge. However, product reviews and forum posts from some individuals claim that they get a "razor sharp" or "shaving sharp" edge on a Cold Steel machete.

In short, can anyone tell me what process they used to get a Cold Steel 1055 carbon steel blade to a literally hair-shaving edge ? Am I the only person who has trouble sharpening these to a razor's edge, or are other people having trouble as well ? It seems like it'll take more than just "a little work" to get these blades hair-shaving sharp. Any advice, insight, or constructive criticism would be appreciated.

Thanks,
Lotus Leaf
 
I use a good file to form a Burr and smooth out the edges before i even try to get a shaving sharp edge some guys use power tools to do this paper wheels belt Sanders then you can use your DMTs to finish of course there's no limit to how sharp or polished you can go depends how much time you want to spend. In other words you have to start with a good even profile it took me a good hour to just to get my cold steel machete in decent cutting shape. Hope this helps. Rich
 
Not sure what the issues might be except that 1055 (and 1075) and other common machete steels aren't going to be as high RC as a smaller knife blade. They can be worked very quickly and with relatively little pressure. Make sure you aren't making the angle too obtuse - the metal comes off fairly quickly and its easy to inadvertently change the angle. I have three CS machetes in 1055 (two now as I gave one to a buddy). Sharpened all three the same way initially. Use a file to form a nice clean bevel both sides - don't raise more of a burr than necessary. From there I used a 1200 grit King waterstone and stropped on newspaper. The one I gave to a buddy I went over with a 4000 and 6000 grit King but only improved the edge a little bit. All three can treetop leghair and dryshave facial stubble. I went through a period where I did a bunch of machetes using this method - the CS ones, a Tramontina bolo, and a Imacasa Daga. They all turned out the same - very sharp.

I've also had very good luck simply using a Norton combination SiC stone. After sharpening on the fine side I wrap a few sheets of newspaper tight around the stone and lightly rub it with some white buffing compound. Strop on that and the edge is as nice as the waterstone edge. I used this on a Marbles (Imacasa) jungle machete and it turned out very well. This also how I maintain my machetes unless they get really beat up - sometimes I'll use black emery compound and then move to the white stuff - they seldom need to go back to the stone if I stay on 'em. These aren't uber polished edges tho they do turn out pretty smooth and don't take very long. The file work is important - do it well and the stone work goes fast. You could do the rough work with a coarse stone, but the file goes a lot faster and cleaner.
 
I used to use a 12 inch single cut bastard file followed by a long aluminum oxide hone. They make some files and hones just for conveniently sharpening machetes: http://www.machetespecialists.com/maac.html

Nowadays I mostly use my large tabletop belt sander followed by a little deburring with an extra fine diamond hone.
 
Thanks for the advice. The general gist I got from the above posts were to use a file, which I tried, but didn't really get much of an improvement. Maybe I need to work on keeping a consistent angle? After some frustration, I'm taking a break on the machetes right now. Maybe I'll try again in the future when I have more patience, and if that fails, I may take it to a professional or a belt sander. I'm hoping reprofiling the edge once will make it loads easier to maintain in the future.
 
You can try using a C clamp to hold the machete steady - elevate it off your bench with a piece of wood scrap. Wear heavy gloves or use a file with a guard and file into the edge. Light pressure and use a Sharpie. The file will skate at first till it starts cutting and then you'll feel it going to work. In all reality you could probably just use a file and get it plenty sharp - the edges look good too - use a single cut, smaller file - maybe 6" (the smaller the file the finer it cuts generally).
 
I think your problem may be the lack of a consistent angle. I usually use a 1000/6000 grit waterstone for my knives, and I too get some burrs after the 1000 grit which makes it feel sharper than it really is. At first my angles werent consistent using the 6000, so I could never achieve that razor edge even when using 1095. You have to find a technique that allows you to keep a steady angle, and from there its just repetition. Whenever I rush to get it done it doesnt quite turn out so well as opposed to when I really take my time.

1055 can indeed become just as sharp as 1095, as I found out with my cold steel trail hawk. It has a convex edge that I sharpened using a mousepad and sandpaper. In this case I needed steady pressure as well as angle... and a lot of repetition.

Also, as far as stropping goes, I suggest you invest in some Mothers Mag alumunim polish($5). Its a metal polishing paste, but it works better then honing compounds and other pastes I've tried on a strop. The best stropping device I've come across(better than leather) is just a piece of cardboard(cereal box kind) taped onto a flat piece of wood. Smear some mothers mag and then youre good to go. This will give you the best mirror polish, and if kept at a steady angle, a scary sharp edge!
 
@HeavyHanded - I've been doing that exactly, for both convenience and safety.
@viper2788 - I would normally use my benchstones for my blades, but the machetes are too large, so sharpening them as I would normally is too unwieldy. Not to mention that the Kukri and Kopis machetes have inner curves that are difficult to reach by benchstones. My current strop is some vegetable tanned leather glued to a 2x4 and smeared with 1 micron diamond paste. Gives a great hair-splitting edge on a lot of my other knives.

I'm going to try again with the file. Then I'll try to refine that edge a bit with the rougher sandpaper. For the sharpened Cold Steel machetes, have you guys just matched that edge, or have you guys done some reprofiling?
 
I do all my machetes to around 32 degrees inclusive and they hold up pretty well. I little bit of convex doesn't hurt either. It is possible to take them to a benchstone, just work it in small sections and overlap as you go. Well worth learning how to do this - lets you use any stone you want to work on them. Even the recurves can be done this way if you radius the edge of your bench stone.
 
Worked on the Kopis machete. After holding up the length of the machete's edge parallel to my line of sight, I saw that bevel is uneven on both sides. One side had a smaller angle, enough so that the bevel looked almost like a chisel grind. The larger angled side also was a bit rounded out, I guess maybe like a convex grind. After like an hour of filing, I was able to flatten out that convexish bevel to more of a cantled edge and bring down the larger angle a bit, but it was still noticeably larger than the other side of the bevel. I also filed down the smaller-angled side a bit as well. Instead of using the rubber sanding block, I then wrapped 80 grit paper around the file, matched that to each side of the bevel, then sharpened away for a bit. I then did the same with 320, 1000, 1500, and 2000 grit paper that I used with water. The result is a bit better than what I described in my first post, but still doesn't feel "knife sharp." Sorry if the terms I used are a bit confusing.

In any case, I think it's much sharper than the factory edge.The bevel should be a bit narrower than when I started this thread (which was after one sandpaper progression) and has a near-mirror finish. It also goes through water bottles much more easily than when put my first post. It can roughly pop off skin from my arm, and the occasional hair, but it still isn't quite razor sharp. It still requires quite a bit of draw to cut paper.

I think I'll try what HeavyHanded mentioned on benchstones. I feel like sharpening recurves would've been a lot more difficult with my older DMT stones, which are not continuous diamond, so the edges of my stones would have had less surface of abrasives. Since then, I've acquired a new set of continuous diamond stones (I didn't get them for the issue with machetes), which I hope will serve better with the recurves. I think I'll try out the stones on my Kukri machete first since it's smaller and easier to manage. Any advice on getting that recurve would be helpful.

Thanks,
Lotus Leaf
 
Diamond plates are not a good choice for recurves - there's a good chance you'll tear the diamonds out along the edge of the plate and still not be able to hit the curved portion well. A better move is to get a solid stone (waterstone, India stone, silicon carbide) and grind one long edge down so it has a rounded profile - I've done this to all my stones for just this purpose. You could also wrap sandpaper around a dowel - you need to have an abrasive surface with a curve you can work against. Use a Sharpie as well. Sounds like you're on the right track.
 
The first time you reprofile a badly ground machete with a file I would expect to spend a solid couple hours leaning heavily on the file. I wouldn't even look at another sharpening device until the file edge felt really sharp along the whole blade. I would file at about 15 degrees per side. This will leave a burr, but it should cut like crazy and not shave at all. After that I might try some sandpaper on the file, but don't push too hard and don't round the edge. Use a few edge-first strokes on your finest diamond hone to knock off the burr. Now strop with light pressure to avoid rounding the edge. From now on try sharpening much like a regular knife blade.
 
The initial edges on all my CS machetes were really horrible. I resharpened them with my belt sander. I sharpened my Panga with a 220/1000 combo stone and strop a couple of times, then got really motivated to fix my belt sander.
 
@HeavyHanded - thanks for the advice on recurves. I certainly don't want to shear off the diamonds :eek:. Unfortunately, I don't have any water stones on hand anymore. My sanding block has a small portion that's rounded like a dowel, so I guess I'll use that after I try filing the edge. Or I just might tape the paper to file like I did with the Kopis.

Something I noticed when feeling the edge on my Kopis machete is that the edge doesn't feel "toothy." Could the micro-serrations have been smoothed out? I'm sure the bevel is narrow enough, but it feels very smooth. I compared this to a katana I have, which I'm certain has a bevel that's a bit wider but more "toothy," and my katana has less trouble cutting paper. Just throwing a thought out there - I still have a lot to learn in sharpening.
 
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Jeff Clark said:
The first time you reprofile a badly ground machete with a file I would expect to spend a solid couple hours leaning heavily on the file. I wouldn't even look at another sharpening device until the file edge felt really sharp along the whole blade. I would file at about 15 degrees per side. This will leave a burr, but it should cut like crazy and not shave at all. After that I might try some sandpaper on the file, but don't push too hard and don't round the edge. Use a few edge-first strokes on your finest diamond hone to knock off the burr. Now strop with light pressure to avoid rounding the edge. From now on try sharpening much like a regular knife blade.
Click to expand...

This is good advice. The initial file work is extremely important - to Lotus Leaf, use a Sharpie if you aren't already and take your time with the file. Use a single cut mill file and when you've raised a burr and flipped it, go back and use a draw file technique before moving to any other method (page 5 of this PDF) http://www.evenfallstudios.com/woodworks_library/nicholson_guide_to_filing_2006.pdf.


And keep in mind the 1055 is "soft" and very "plain" in that it probably hardened to RC 52-54 and has no alloys or added carbides compared to other steels you might be used to. Use very light pressure and check often for best results. In my experience, its possible to strop most of the tooth from this steel very easily, esp if sharpening to a fairly high grit to begin with. This is not a bad thing for a chopper - extra tooth will actually increase resistance. However, its also very easy to round the apex over when stropping or working with the finer abrasives. I highly recommend you make a few marks across the bevel with a Sharpie before stropping so you can see exactly where you're hitting - entirely possible this is where you're having trouble.

IMHO you should try to sharpen the thing in sections - a machete is way to large to reliably manage full sweeping movements and maintain a steady edge angle.
 
Lotus Leaf said:
@HeavyHanded - thanks for the advice on recurves. I certainly don't want to shear off the diamonds :eek:. Unfortunately, I don't have any water stones on hand anymore. My sanding block has a small portion that's rounded like a dowel, so I guess I'll use that after I try filing the edge. Or I just might tape the paper to file like I did with the Kopis.

Something I noticed when feeling the edge on my Kopis machete is that the edge doesn't feel "toothy." Could the micro-serrations have been smoothed out? I'm sure the bevel is narrow enough, but it feels very smooth. I compared this to a katana I have, which I'm certain has a bevel that's a bit wider but more "toothy," and my katana has less trouble cutting paper. Just throwing a thought out there - I still have a lot to learn in sharpening.
Click to expand...

How did you sharpen your katana? Thing with my Kaze katana is that the edge geometry isnt uniform throughout... basically theres more "niku" or meat/convexing towards the handle part of the blade, whereas its more of a scandi grind towards the tip. This gave me a lot of trouble sharpening... esp stropping as I would have to slowly change angles going down the entire blade.

That being said, I believe my solution may help you in your case... with any blade actually(esp curved blades). What I did was I cut up sandpaper into little squares the size of stamps and ran them down the edge with my thumb(diagonally), flat against the grind. Your thumb would act sort of like a mouse pad and gently convex the edge... except you can get a MUCH better feel for it. You can easily control the amount of convexing, or in my case, I barely convexed it at all and actually did some sharpening this way. I believe its the feel of it that allowed to be give a better edge than other sharpening methods. Also visually, I'd look down the blade while sharpening as I would aim with a rifle, giving me more feedback. I would move up in grits the same way just as I would sharpening otherwise. I went and did the same thing with the "stropping." I cut up a pair of jeans into squares and applied the Mother's Mag(can be any stropping compound/abrasive) and did the same thing... applying very light pressure over the edge(barely any) as you would do with a flat strop. In about 3 hours, I was able to get the entire 28 inch blade beyond shaving sharp... with a bit of convexing that is(in theory it should be tough)!

Recently I touched up my mini griptilian this way. I did the thumb/sandpaper thing with 1500 grit and then used a flat strop. took about 10 minutes =)

I would recommend this method for semi sharp blades only... really dull edges should be re profiled otherwise first. Hope this helps
 
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@HeavyHanded - I think I've been drawfiling when using the file (basically holding the file with two hands, applying pressure to the edge, and sliding it back and forth in small strokes, slowly traveling up/down the blade), but I'm not sure if that would be the official term for what I've been doing.

@viper2788 - I was referring to the katana's factory edge; I haven't dared attempt to sharpen my katana yet. I also like to look down at the bevel as you describe like a rifle to see where I'm at. That thumb/sandpaper technique seems a bit dangerous to me (since I'm quite uncoordinated and prone to clumsy accidents).

I'll take the Kukri out tomorrow with the file and mark the edge with Sharpie. Before I just looked at the grind marks against the finish I started with to see where how far I need to keep filing, but some extra assurance shouldn't hurt. I'll try to set aside much of tomorrow to try and get this done. I'll also try to use less pressure on my higher grits to prevent rounding the apex.

Thanks again guys for your advice.
 
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