Steeling a Lum Chinese (VG-10)

[Cliff Stamp]

One of the most common advices given about sharpening is paradoxically to avoid it by steeling/stropping to delay the time between sharpening. This is usually argued for on the basis of sharpening being either extremely complicated or very wasteful/hard on a knife. Neither of these need to be true, sharpening can be very quick/efficient with a little understanding and sharpening doesn't need to actually remove any material from the width of a knife at all practically, again with a little knowledge of sharpening.

I have never been much of an advocate of steeling for a number of reasons, the main one being if you are going to steel then you are using an edge in a quasi-deformed state so all of that time/money/effort into making a quality steel to produce a very strong/tough material is being sacrificed as you are deforming the apex which leaves it more brittle/weak (in regards to specific loads). But recently I did a little experiment to look at this in some detail, more on a request than anything else as again it isn't something which is of significant interest to me.

To start I used a Lum Chinese in VG-10 which has been reground to a full height convex grind which ends in an edge which tapers to 5-6 dps right before the apex. It is sharpened with a micro-bevel at 15 dps with a 600 DMT stone. The knife was used to slice 1/2" hemp until dull and then calculate edge retention statistics. Then I then used a nitrided rod made by cKc knives to restore the edge to optimal at 20 dps and then repeated the cutting and the statistics. This is what the edge looked like after a few steeling runs :



The part above the red line is the steeling bevel, the part above the green line is the DMT bevel, the rest of it is the finish from the shaping stones. I did a number of steeling runs using very light force on the nitrided rod (just barely made contact) and ended with one which was forceful (a few lbs of force) to see what happened in that method. In short, th the high force method doesn't work well at all, it smears out the edge and it loses all slicing aggression and is very weak. The ideal method is to use very low force, barely make contact and alternate passes as much as patience will allow.

The results look like :



Now this is only one run and it is all connected to the first sharpening run so there could be a significant bias in the data, but still at this stage a few general observations can be made :

-the steeling times are very short, < 10 seconds
-the knife can be steeled 10+ times and still have functional edge retention
-the edge retention looks to be decreasing with repeated steeling, but stays functional for a long time

In fact if you look at the total edge retention it is ~5X the initial which means that this VG-10 blade easily has higher edge retention than any steel I have used (as steels don't offer that much more edge retention on hemp, a factor of +/- 2X will span almost all cutlery steels). This isn't at the limit of steeling so it is possible that it might be as high as 10X or more before steeling stops being effective at all.

Does this mean edge retention data is pointless because you can just steel edges? Well no, not even close. Not all materials are like hemp which is very soft and not very abrasive. If you try the same thing with cardboard and even worse, something like carpet, you won't get that kind of response as the nitrided rod won't be able to restore the edge the same way as it will be heavily worn and gouged, just just lightly deformed as happens with hemp.

There is also another issue and in retrospect maybe this wasn't the ideal knife to use, or maybe it was as it showcases something interesting when I tried to repeat it again. I ground off the edge and reset it and then applied the same micro-bevel, however this time in less than 10 cuts on the hemp the edge was damaged beyond the depth of the apex bevel :



+



I ground the edge off and tried it once more :



Can you conclude steeling is useless because it causes fatigue to the edge which makes it prone to fractures (which looks like what this is showing). Not in general, no. This is a relatively hard, high carbide steel in a very low edge angle which is almost at the failure limit for this type of cutting and thus even a small weakness will be magnified. I don't think the same thing would happen if the edge was at 10 dps, or if the steel was inherently a much more stable and fatigue resistant type (low carbide/high strength/high purity).


In short :

-steeling may increase edge retention to very high levels with almost no effort/time spent
-it can retain slicing aggression in repeated cycles (10 times)
-very high force tends to be a negative
-there may be issues with steeling very high carbide blades sharpened at very low angles

This also might be why so many people warn about steeling Japanese blades because of the high carbide and low angles they are much more sensitive to long term fatigue than the much lower carbide and higher angle western type blade materials (5Cr13).

--

I am not sure if I will look at this in more detail because again it really isn't something I am practically interested in, though there are obvious questions to be asked such as what would happen if :

-I didn't do that very high force steeling run at the end
-If this was white steel
-Or AEB-L
-Or maybe 121REX/Maxamet (are they worse again)

There are also some very interesting questions such as :

-what edge angle stops the fatigue failures (or what carbide volume)
-at this edge angle just how much greater edge retention can you get
-does it work to any practical extent on something dramatically abrasive like fibreglass or carpet
-is there any difference between 1095 vs White steel (purity has a strong effect on fatigue resistance)

This is course what happens any time you apply a little science to anything, you learn a little bit about something and you immediately see dozens of questions which reveal you were ignorant in ways you didn't even know that you didn't know.

[bh49]

Cliff,
Thank you for sharing. I am not steeling even my kitchen knives, still very interesting.

[Cliff Stamp]

I am not steeling even my kitchen knives, still very interesting.

Yeah, I don't either as kitchen knives for me blunt in a few ways :

-I don't strictly follow the Japanese two-towel method and corrosion sets in on the White/Blue type steels
-People not "into" knives use them and they are just damaged
-Preparing dirty vegetables (lots of small local farms)

If I can avoid that then I can use a knife for a very long time (much more so than weeks) and they still easily slice a tomato with no slipping. The problem is though that trying to avoid that perfectly for month+ isn't trivial. It only takes one accidental impact to do more blunting to an edge and it takes more work to carefully wash / scrub vegetables than it does to sharpen the knife after peeling.

Still though, just looking at the data in one light and seeing a 5-10X increase in edge retention isn't trivially ignored. This can be further expanded if you use a grooved steel on a knife which can actually be filed. In that case it would not be unexpected that the average person may only need to sharpen a normal 5Cr13 knife once a year. It might also further be the case that what would commonly be called the "better" steel might actually be worse due to not having the fracture and fatigue resistance or response to the pseudo-filing.

--

As a side note. I have used the Lum a lot lately for these types of comparisons and it has really grown on me. It is unfortunate that I snapped the clip off almost immediately when I got it because of back pocket carry.

[bearfacedkiller]

Thanks cliff. I have always avoided both stropping and steeling because I believe that you are better off just creating a fresh clean apex of unstressed and undamaged steel. I never had any evidence either way and it has always just been my theory and practice. I enjoy extremely sharp edges for edc folders and question if stropping or steeling is good for maintaining extremely fine hair popping edges. They don't stay that sharp for very long and any reduction in edge retention is not good for my preferred edge and uses. Sounds like a steel could be a good option for some situations but not for my edc folders. I don't find maintaining edges with a sharpmaker all that difficult or all that time consuming.

[Bugout Bill]

On high grindabilty steels, you sort of reach a point where you could resharpen with just as much effort as you could steel it.

With my Superblue Endura, I've found that 10 alternating passes on a Norton India are sufficent to return high sharpness, even if the edge is blunted from cutting in ceramic or glass.

[Cliff Stamp]

I don't find maintaining edges with a sharpmaker all that difficult or all that time consuming.

That to me is pretty much the critical part and it is at the heart of why steels are often difficult to advocate. Now if you roll back the years and you compare using a steel on a kitchen knife to having to break out oil stones then you are looking at a very different process. It isn't at all the case that you could stop in the middle of a meal and take a break to sharpen the knife on the oil stones and so another option which allowed you to continue with just 5-10 seconds jumps out as very useful. Lets even accept that the edge retention after steeling may be significantly lower, say 25-50%. If steeling is literally a few seconds does this actually matter? This is why a lot of people just get in the habit of steeling an edge before they start to cook a meal, it easily lasts through one meal unless you do a lot of bone work (like filleting) and if you do well another 5 s and you are ready to do again. If you use the Japanese approach to preventing corrosion then that takes much more time than steeling.

I think an interesting knife to use might be one of the MBS-26 kitchen knives from Spyderco because it is not only a kitchen knife which are frequently steeled, it is right in the middle between high carbide steels like VG-10 and the low carbide steels (5Cr13) which are typically steeled all the time. Still though, even if this works, even if the results come out ideal and you can get say 5-10X the edge retention (on hemp) what does this really gain you if you simply went to the Sharpmaker instead of the smooth steel. It is just as fast and in fact you can easily get back to almost identical sharpness/edge retention if you use the brown rods to start to remove some weakened metal and finish on the fine (for most work). Or for really coarse cutting like cardboard and carpet, just use the CBN rods. It therefore can not only act like a very fine / smooth steel or simply reset the edge directly.

[Cliff Stamp]

On high grindabilty steels, you sort of reach a point where you could resharpen with just as much effort as you could steel it.

There is this, and I think this is where a little knowledge of blade materials and sharpening go a long way. For example knowing which abrasive to use and how to take advantage of micro-bevels are key to being able to sharpen a knife very quickly and keep it sharp. But as you said, at some point, when you hit steels which are very easy to grind, assuming you are not really afraid to sharpen - the time can be very fast. Geometry is key here as well and with a little knowledge of that you really reduce the effect that grindability has on sharpening time. If you have the money for modern abrasives that also makes a big effect. For example switching from a traditional steel to a 1200 grit diamond or 600 grit diamond or ceramic rod is certainly a choice to explore.

[Brock O Lee]

I have a fine ceramic steel in my kitchen, and a bunch of cheap noname stainless steel german kitchen knives. I have seen edge retention drop after a few steelings compared to a freshly sharpened edge. My wife is the primary blunting agent in our kitchen, hence the cheap knives... :)

Even so, I can maintain a tomato cutting edge for many weeks with a few steelings, so it feels worthwhile to me. I have often wondered where the sweet-spot is in terms of the coarseness of the steel to steel with.

As I understand, if the steel is just smooth glass, it will only fold the edge back into line, so it will align the edge but also create stress in the edge without removing any damaged steel.

If the steel is coarse like a diamond rod, I suppose it both aligns the edge and removes some damaged steel to a certain degree. My question is, do diamonds also align (and as a result stress) the edge, or do they cut fast enough to cut a fresh edge with a few swipes on an edge that starts to slip on tomato?

My gut feel is that it may be easy to just have a Sharpmaker with diamond rods as a permanent fixture in my kitchen, and show my wife the basics on how to use it... She is not mechanically minded or have an over-abundance of patience. So, it's a bridge too far to ask her to reset the edge, check for light reflecting while she sharpens, apex at light force on a higher grit, deburr at a high angle and backsharpen, then micro bevel in a few passes at super light force on the grit of her choice for her intended application ! :D

[Laethageal]

I have a fine ceramic steel in my kitchen, and a bunch of cheap noname stainless steel german kitchen knives. I have seen edge retention drop after a few steelings compared to a freshly sharpened edge. My wife is the primary blunting agent in our kitchen, hence the cheap knives... :)

Exactly the same at home! I got a bunch of cheap knives I let her use and sharpen only once in a while. I can't get her to stop cutting directly into the ceramic dishes. When she goes saying the knives don't cut anymore, I give them a few quick pass on a Forschner diamond oval steel (I'd guess about in the range of 600 grit) and does bring a level of sharpness which is good enough for her.

[PayneTrain]

Cliff, you mention possible problems with the edge high carbide steels, but the question I've always wondered is will these high carbide steels, possibly being harder than the sharpening steel, ruin that steel, especially if it is the ribbed kind like I am used to? I've never seen a nitrided one, just bare metal and I'd say only once was it smooth and not ribbed. It seems they wear with use (as most things do), and I wonder if using them on a high carbide steel accelerates that wear, or are they hard enough themselves that it wouldn't make much of a difference vs the soft steel of those cheap scimitars I mentioned in another thread of yours.

[arty]

The usual advice is to never steel high chromium steel, but only softer german carbon steels, or carbon Sabatiers. I used to use a steel on my 4 Elephant Carbon Sabatiers, but I have transitioned to kitchen knives in VG10, XHP, S35V, and 440C. I would never use a steel on a Gerber M2 blade. Steels are for softer carbon steel. I am not referring to a "steel" with an abrasive surface, but the old fashioned steel designed to straighten rolled edges, sort of like the chakma that is supplied with traditional kukris.
I do use a strop from time to time, but that is rare.
Cliff's results confirm what people in the kitchen knife forums have been saying.

[sal]

John Juranich produced a pair of hard highly polished steel rods as part of his offerings. Don't know if he still makes them. I removed them from their holder and use them in the slots of our white ceramic triangles at the same angle just used (30 degrees in my case). Interesting results. They do feel a tad sharper and seem to stay sharper longer. I've thought about producing a pair of highly poished hard smooth rods as an accessorhy to the Sharpmaker.

sal

[Chum]

John Juranich produced a pair of hard highly polished steel rods as part of his offerings. Don't know if he still makes them. I removed them from their holder and use them in the slots of our white ceramic triangles at the same angle just used (30 degrees in my case). Interesting results. They do feel a tad sharper and seem to stay sharper longer. I've thought about producing a pair of highly poished hard smooth rods as an accessorhy to the Sharpmaker.

sal

Interesting idea, especially if they could somehow fit into the existing Sharpmaker cases.

[dbcad]

Good Topic :D

I can see intuitively why high carbide (more brittle) edges aren't suitable for steeling. The edge would just start start snapping off :eek:

Seems to work well with vg-10 and Superblue for me with a cheap Farberware steel, for a few times at least

Steeling is great for literally stretching the edge for as long as you can with lighter use. Know your blade material if you want to steel and have a clear idea of what you're trying to do :)

[Cliff Stamp]

My question is, do diamonds also align (and as a result stress) the edge, or do they cut fast enough to cut a fresh edge with a few swipes on an edge that starts to slip on tomato?

It depends on the diamond grit, the common ones are 600 grit and are very aggressive, they cut off steel immediately and do little alignment.

My gut feel is that it may be easy to just have a Sharpmaker with diamond rods as a permanent fixture in my kitchen, and show my wife the basics on how to use it.

I believe Spyderco used to sell a much simpler system just for that, the Galley V.

Cliff, you mention possible problems with the edge high carbide steels, but the question I've always wondered is will these high carbide steels, possibly being harder than the sharpening steel, ruin that steel ...

That is an excellent question and a lot of people talk about it and some people even recommend using a light lubricant on the steels in order to prevent it because many modern high carbide steels contain carbides which are much harder than even case hardened steel rod. However, and this is an interesting point - without lubricant you will also get some manner of adhesive wear. The only real evidence I can give is that Alvin Johnston, who used to make knives for butchers, would note that they common did have to repolish steels. The knives he was making for them were of full hard 1095 (66/67 HRC) and full hard M2 (64/65 HRC). It might be an interesting experiment but man you would need mega-patience for that given the extremely low rate of wear unless you wanted to try abusive steeling to try to accelerate it and I am not sure then that the wear would be similar.

The usual advice is to never steel high chromium steel, but only softer german carbon steels, or carbon Sabatiers.

I am really curious if that is due to the hardness or the carbide volume. I have lots of very nice, very hard blades in low carbide, high apex stability steels, even white/blue steels which are very high purity. It suggests an interesting experiment.

[Cliff Stamp]

Here is an update :



That is the result of the same basic procedure with a very basic 3Cr13 stainless steel knife (EveryDay Essentials Chef - $1) . I did three complete cycles of runs of 12 in general and there was none of the edge breakout as noted in the above. As I was able to do multiple runs I was able to put error bars on the results which is critical in being able to conclude any patterns visible.

For each cycle the edge would just go from this which is a 15 dps 600 DMT micro-bevel on a ~5 dps edge polished with Naniwa Aotoshi 2000 :



To this at the end of a steeling run :



Note the strong deformation and lack of fracture. This is a very tough steel, it would be surprising to see it fracture even when fatigued.

As a few observations :

-the initial edge retention is lower than the VG-10 knife
-the total edge retention for one run of all steeling cycles is higher than any steel potentially
-there is no issue with the edge fracturing
-the steeling time is very short, even at the last cycle

However I will say this, steeling is a lot more complicated than you might assume. The edge retention is strongly influenced by the quality of the steeling. The five rules of steeling are :

-go extremely light
-alternate passes
-go extremely light
-do not over steel
-go extremely light

In case it isn't obvious - you have to use very light force, if you don't bad things happen :

-the edge smears, you lose all slicing aggression and it collapses very quickly in use

If you over steel and continue past the point it is optimally sharp the the same thing happens but not as much. Now of course if you are not spazzing about minute details you don't obsess about this in use, all you do is very basic :

-make a few very light alternating passes
-check sharpness
-repeat if necessary

If you go a little to far all that happens is that you will notice the edge degrade too rapidly in use so you make a mental note to use maybe a little less force and more passes next time.

As a final note, I don't think that large initial drop off is due to steeling. I believe it is mainly due to a combination of :

-increased polish
-increase apex angle

More experiments are needed to confirm however.

[Cliff Stamp]

As an update, to confirm a few things I repeated the work on the 3Cr13 knife but this time reduced the grit of the initial finish (MXF DMT) and tried to steel vs close to the original angle :



In short :

-the edge retention of the MXF is lower than the 600 DMT (both with a 15 dps apex)

This is expected as it is slicing a harsh/abrasive media so the more coarse finish has better edge retention. However what is interesting is :

-the steeled edges have better edge retention in the MXF case than in the 600 DMT case

This is mainly because I am comparing a steeled 20 dps edge on the 600 DMT bevel vs a ~15 dps steeled edge on the MXF case as I was trying to see if you could retain the edge retention of a polished edge if you steeled at the same angle. The lower apex angle gives higher edge retention.

In super-condensed form - it appears you can steel an edge and retain similar levels of edge retention as long as the initial apex finish was also highly polished and you steel at a similar angle -and- the material you cut isn't that harsh/hard to cut.

--

I also played around a little to see what would happen if instead of doing a few heavy strokes I did a lot of light ones as first I was curious if I could obtain some kind of uber sharpness (didn't happen) and then became curious what would happen if I would continue. The push cutting sharpness does get very high, but then starts to decrease slightly and the slicing aggression slowly is absolutely lost. I believed it was nothing more complicated than the apex being bent/hooked over (like you burnish a cabinet scraper). I confirmed this by doing some ultra-light, barely making contact passes until I could and shave on both sides and the slicing ability was again restored to high levels. I think this is another of the reasons why people think polished edges have low slicing ability as they are simply folding over the polished edges when they go to the fine abrasives because they tend to have a strong ability to deform material vs abrade it. This is why it can often be easier to get slicing ability with coarse edges inherently.

--

It might be interesting to try this kind of steeling with Spyderco's MBS-26 knives or the LC200N knives and see if they behave inbetween the above, or more like one or the other. In any case there is more to steeling than you might imagine, and if you do in general light cutting which doesn't tend to damage edges, you might want to look at a steel, especially if sharpening is something that really stresses you out. It might also be something you introduced to your friends/family to postpone the times they ask you to sharpen their knives. The only thing I would say is when you do go to sharpen a knife which has been steeled you really want to cut some of that metal back or else you are not going to like how it sharpens.

[Cliff Stamp]

Here is some more data doing similar (not mine) :



I plotted it another way to show the non-linear relation and the kind of scatter you see in hand cutting/sharpness measurements.

Note that it shows how with steeling, you can get back to the original sharpness (within the bounds) even after significant cardboard which is far more abrasive than foods. This is why a lot of people like slicks/smooth-steels in the kitchen. With proper light use then knives can be kept working sharp for a very long time as long as they are the kind of blade materials which react well to repeated steeling.

[me2]

My old Food Network petty (RIP) was my trial at steeling. It behaved similarly to the Carter knife in the graph above. I could cut cardboard for a while, and as long as I was paying attention and didn't let it go too long, I could steel it on the spine of another knife with very light passes and it would be like new. However, let it go too long and the steeling just made noise and would only get the edge back in the most basic sense. I think I went 4 or 5 rounds of cardboard/steeling and then quit when I ran out of cardboard.

[Cliff Stamp]

Chris, there is a bit of an interesting question which comes out of that though which is - since the sharpness can be brought back so effectively on this class of steels, how important is edge retention really for that type of cutting?

Now this doesn't mean in general that holding a sharp edge and the properties which make it happen are not useful, there is some cutting which doesn't lend itself to steeling.