All was quiet in the razor world until Murray Carter of Carter Cutlery, an ABS Master Bladesmith and 17th Generation Yoshimoto Bladesmith, decided to make a straight razor sharpening video.

Those of you who do not know Murray Carter should know that he is probably one of the more controversial knife makers out there, and his sharpening techniques almost always come under fire on forums everywhere. At the same time, he is highly respected, and just as many people love his techniques and defend them on forums everywhere. 

We’ll get to the videos in a minute, but before we go further, I’d like to say that I have no axe to grind (pun intended!) with Murray Carter and his techniques, or any of the people mentioned in this post. The purpose of this  post is to respectfully offer more tangible evidence and arguments than those who have argued with Murray Carter and his techniques surrounding this saga.

This post is colossal,  and covers a great deal, but I feel it is necessary in order to cover the huge range of accusations and counter arguments that have flown back and forth regarding the first video, which we will watch now:

If you go to the actual youtube video and read the comments, you’ll find that this caused quite a stir in the straight razor community, and provoked the following video response from Brad, aka Undream22, who, by the way, does downright amazing razor restores:

While Brad is certainly respectful in his video response (it’s more of a friendly challenge), it lacked any technical details as to why tape and slurry were used (not that Brad doesn’t know why, he just failed to state more detailed reasons in the video), and were two of the points Murray covered in his response video – along with edge trailing vs. edge leading, and a hanging strop vs. a paddle strop, as seen below.

Before we continue, Murray’s second video must be viewed in the correct context – it was a reply to what amounted to outright bashing by certain members of the shaving community.

EXPERIMENT

1.0 – Carter’s method re-created

The initial reaction from the straight razor world to Murray’s first video above was essentially “you can’t do that”, “it’ won’t give a smooth shave”. To be more exact, “we don’t do it that way in the straight razor community” is pretty much the point those involved tried to make. Personally, I am on my own honing/sharpening journey, and while I may or may not agree with everything about Murray’s razor sharpening method, I don’t want to be an armchair critic. So to find out for ourselves, several of us from the Badger and Blade (B&B) forum tried to recreate Murray’s method as per the first video. You can read the entire B&B thread here.

In the first video, aside from getting a burr on the razor with the 1K, Murray took very few strokes at each subsequent level. I actually sat down with Michiel Vanhoudt (check out his Belgain Sharpening blog) and he watched the video while walking me through how many strokes as I honed up my Boker Red Injun razor. I took microscope pictures at each stage with my Veho USB microscope at 400x, with the actual picture size being 1mm wide by .75mm high. While I do have the King 1K and 6K stones and people do use them in razor honing, I don’t prefer them. I used a Chosera 1K and a Shapton Glass 6K stone instead. I realize these stones work differently, but it’s the method that was in question here, not the stones themselves.

The major differences between “traditional” razor honing and Murray’s method is that traditional methods advocate not pressure on the blade, using any one of several stroke patterns, with the most common being the “X-stroke”.  This usually results in more overall strokes, and a “sneaking up” on the edge of the edge. Murray’s is much more related to knife sharpening, where he goes in a back and forth motion on one side until a burr forms, then switches sides and goes back and forth until a burr forms again.

Up first was the Chosera 1K edge, edge leading

Boker 1K Chosera

You can the the edge is established and would look almost the same if “traditional” straight razor methods were used (no pressure, and single-sided, alternating strokes). One thing in common at the earliest stages of razor honing and knife sharpening is that Razor honers also employ the use of circles at the lower grits for bevel setting, which is certainly no stranger as a knife sharpening stroke.

Boker - 6K Shapton Glass

According to the 1st Carter video, he took only 2 strokes on each side with the edge now trailing. You can clearly see the criss-crossing and overall mess on the bevel, however, there was some improvement to the edge of the edge, along with a hint of more polish, Overall, you can see the 1K Chosera scratches going from the top left to bottom right, and the 6K from top right to bottom left. Note, however, the vertical lines, which are from going back and forth on the 1K to establish the burrs from the first step. The 6K has not fully removed the deeper scratches.

Boker - Balsa Wood Deburr

The deburr was not really necessary in my opinion, but I can see people without any honing or sharpening experience creating burrs that would need removal, since in knife sharpening, there is much more likelihood of a burr being formed.

Boker - 2 more 6K Strokes

Then onto 2 more strokes, edge trailing on the 6K. Now we can see a clear “polishing of the grooves” as denoted by the concentration of blue hue at the edge of the edge, which are still really 1K scratches as indicated by their direction.

Boker - 2 Strokes HA Chromium Oxide

Now Murray says you don’t need to do this step, but trust me – you’ll want to He also says any old Chromium Oxide will do, and this is true -  but the stuff from Hand American is tops   . You’ll note at the edge of the edge, there is a straight line, despite all the scratches still evident. This is a promising sight, as the chromium, rated .5 microns, or 30K really cleans up the grooves of the underlying 1K and 6K scratches.

Boker - Newspaper Strop

Lastly, Murray stropped with newspaper, which I wonder if it really has any effect, but won’t go into here. Yes, there is some more shine on the edge, which is indicative of there being more polish, but that could very well be due to variation in the picture – the Veho 400x is good, but not exactly easy to get repeatability. But hey, that’s what Murray does (and a lot of others), and there seem to be enough positive results from it from both the knife and straight razor communities.

SHAVE 1.0

After stropping, the edge passed the HHT – but it seemed to have a little whittling action before the hair actually popped. Nonetheless, it’s still a positive for the HHT test.

The shave itself was a decent WTG with no real pulling, but with some resistance – A basic shaving edge, IMO, so it “passes” in that regard. I was actually impressed. ATG was a bit less comfortable, but it still “worked”. The Bay Rum aftershave gave me a home alone moment that lasted a lot longer than I would’ve liked.

A little bit of perspective is needed here, IMO. If you’re a knife guy coming over to shaving, Murray’s method is a very good segue, and not a terrible introduction to your first straight razor shave.

2.0 – After Speaking with Jason from Carter Cutlery…

Apparently, our efforts over on B&B were noticed, and I ended up on the phone with Jason from Carter Cutlery.  We had a wonderful conversation, and he revealed that the first sharpening video was, in fact, edited, and that Murray did more than a mere 2 strokes per stone.

This opened up the method big-time, meaning that we could get the razor sharp at each level before moving on. It also meant that no matter how much we may agree or disagree on the method, it should work so long as one moves on at the right time – in other words, learns how to maximize the method. It was a huge relief because I don’t think I want to ever feel that much burn again after a shave!

No pictures for this progression, but Michiel Vanhoudt did a wonderful Veho 400x picture progression, here. He also made a video of his shave, broken into 2 parts, Part 1 and Part 2. Our resident crazy Swede, Jens Skandevall, also did a nice shave video using a modified version of the King 1K/6K  method, here.

Here’s what I wrote on B&B about my 2nd shave:

I redid my Boker last night by raising a burr on the Chosera 1K, deburred on a plastic tray (although I did do several alternating strokes on the 1K first), then about 40 laps per side on the 6K Shapton Glass, stropped on newspaper, and jumped to the 30K Glass – all with deliberate knife pressure. I “cheated” and did about 30 laps on the Tony Miller Leather, and the blade passed the HHT quite nicely this time.

The shave this time was a lot more comfortable. WTG was much smoother than the initial try – I’d say a 7 out of 10. I was dreading the ATG, wondering what would happen this time…. but the ATG was actually much better – about a 7 out of 10 again, no real pulling and no immediate indication that there would be irritation. The result was a decent shave, not quite BBS, but certainly good for a first go around with this method.

The aftershave revealed some sting, but this time it was well within acceptable parameters – a light sting that dissipated within 10 seconds (the first shave’s sting lasted more than 5 minutes…)

Conclusions – Murray said it best – that no one can reproduce his hand on his stones with his razor. With no limit on strokes, anything goes, and technique fills in most of the gaps. As this was my first real attempt at this method, I got acceptable results, but since it is new and unknown to me, there is probably a lot of room for tweaking, and gaining enough “time in” to ultimately get more satisfactory results.

3.0 – Doing Murray Carter’s Method “My Way”

Since Murray’s second video has already been published by the time of the 2nd shave, the third one was going to be my best attempt at achieving the most refined edge in the least amount of stones. But since I can’t be Murray Carter, I decided to take what I learned and mix it with what I already knew. Besides, I know I want more than a .5 micron edge on my straight razor

I took the time to document this, and I think we’ll see a rather big difference from the original method, with limited strokes.

Boker 3 - 1K Chosera

There is clearly a much better defined edge of the edge with consistent scratches throughout. The only difference here is that I used “knife” pressure instead of no pressure. You can also see the flexing of the metal by the way the scratches “bend” toward the bottom of the bevel. We’ll discuss this later.

Boker 3 - 6K Glass

The 6K Shapton Glass, edge trailing and with knife pressure, revealed something that counters what Murray talked about in his second video about edge trailing vs. edge leading (which we will discuss in more detail later). I did a “uni-pyramid” on the 6K, starting off with 10 strokes on each side, then 5-4-3-2-1-1-1-1. There was a significant amount of swarf on the stone, which when combined with the pressure seems to have created chips.

You can also see  just how well the 6K scratches are established (from top right to bottom left), and the last remaining 1K scratches (from top left to bottom right). So at this stage, you can also attribute the chipping to “underhoning” which describes chipping that is caused by revealing the deepest scratches left by the coarsest stones when using finer stones.

Boker 3 - 16K Glass

I jumped to the 16K Glass stone next for 2 reasons. First because I routinely jump from 5K to 15K on the Shapton Pros with my knife sharpening without any problems. Secondly, because of the less-than-desirable reviews the 16K Shapton Glass stones receives from the straight razor community, saying it causes chips (which was addressed here).

Anyway, you can see just how fast and even the 16K Shapton Glass stone is – there are no scratches left from the 1K at this point (I only see 2 random ones well above the edge). I used about 10 alternating, edge trailing strokes here, still with knife pressure. The edge looks quite amazing, actually, with no real “polishing of the grooves” as experienced with the 1.0 version.

Boker 3 - 0.025 Micron Poly Dimaond on Balsa

And because I am accustomed to edges finer than 30K, or .5 micron finishes, I used some of Ken Schwartz’s 0.025 micron (640,000 grit!!!) Poly Diamond spray on balsa for 5 strokes, then cleaned it all up with 50 strokes on my Tony Miller Hanging Leather Strop:

Boker 3 - Tony Miller Leather 50 strokes

As you can see, the edge of the edge has become rather consistent and even, the browning is actually leather residue.  I’d say at this point, we have at the very least, removed all the 1K scratches, and most of the 6K scratches. The edge is essentially a very clean 16K edge, with some remaining, yet polished 6K grooves.

Here’s my review of the shave as posted on B&B:

I shaved with the Boker last night and got a very close shave – but just a hair short of BBS. The edge held up for the entire shave, and it seemed to shave closer when I used more pressure. I did 2 full passes. The Bay Rum aftershave burned a little more than the previous shave, but not what I would call out of the ordinary.

DISCUSSION

Before concluding this saga, there are a few more things that Murray Carter has brought up, some which are just not talked about enough: Taping the spine, razors as tools, pressure, hanging vs. paddle strops, and edge leading  vs. edge trailing.

Taping the Spine of a Razor

In Brad’s (Undream22) reply video to Murray Carter, he explained reasons for tape, which amounted to keeping it pretty,  and to make it easier to hone. I think Brad missed the most important reason for taping the spine, and that is for proper edge strength/geometry.

Murray stated, and I think most people agree, that razors have their own built-in jig, or guide, and should be honed flat on the stone. But with today’s quest for precision, perfection and flat hones, I think we have assumed certain things about razor manufacturing and honing processes that are just flawed. The big one for me is that we think razor manufacturers of western razors knew of the optimal edge angles and thus produced the optimal spine thickness to blade height ratio on every razor with their corresponding grinds.

I see it this way -  In the history of razors, they started off more as big forged wedges with softer steel. They needed the thick spines  in order to hold the softer and less pure steel at the edge in place. Hanging strops were perfect for drooping loosely enough to caress the edge of the edge (we’ll get to that more later). Initially, people who owned razors and razor hones were most likely barbers who shaved many people each week. If you look at the constant upkeep that takes, you will see a dished natural hone, and a corresponding convexity to the edge angle of the razor which is more obtuse than the spine thickness to blade height ratio. In other words, a razor was big so it could hold an edge thin enough to shave without  folding over on itself, and it was reinforced by the convexing of the edge. Watch this Popeye cartoon at 2:30 and you’ll see what I mean about the dished hone.

Razors became more and more hollow ground as steel quality improved, and it is my belief that once the industrial revolution began, manufacturers and users expected to have a breaking in period of new razors on old, dished stones in order to create the proper geometry and the thinner steel meant less production costs, increased production speed, and quicker breaking in period for a new razor.

Fast forward to today, where technology has gained incredible speed in the quest for sharpness – flat and precise stones are now what we promote, with constant maintenance. When you get to certain stones like the Shaptons, they don’t break down and form a finer paste – they keep removing layers of steel at each level, making the edge of the edge extremely flat and sharp, yet evermore thin and fragile. (Other stones, like Kings and Superstones dish much more readily to create that convexing of the edge, though.)

Hence, the use of tape in order to artificially create  the proper geometry suitable for any given razor.

An excellent example was this Klas Tornblom hollow ground, which was so thin that it produced a terrible shave because the edge of the edge was too weak to hold up to the strain of shaving.

Klas Tormblom - 16K Glass, no tape

It ended up with 3 layers of tape before it produced a burn-free shave.

Klas Tornblom - 3 layers of tape

This is the real argument for tape, in my opinion. Saving the aesthetic of a razor is secondary to me as well, and as Brad stated, some people/customers don’t want to prematurely wear out the steel on the spine.

Which leads us to our next discussion topic.

Razors as Tools or Heirlooms?

This is an excellent argument that all knife makers seem to have the same stance on, and one that Murray Carter was also adamant about in his reply video – Knives/razors are tools. They are not meant for the altar, and you should use them and they should wear.

One thing Murray may have missed was the fact that many of the straight razors on the market are antiques that are over 100 years old in many cases, and the vast majority of the world’s sought after razors are no longer being produced (the famed Wade & Butcher is only one example).  In my opinion, they should be preserved as well as used. In fact, the best way to preserve them is to use them.

It’s probably better to see it from the perspective of a Japanese sword polisher – if you are given the task of removing the surface rust from a 100 year old Katana, you will not go to town on it – you will actively preserve as much as the steel as you can, while removing only what is necessary. Even if the sword is no longer being actively used, it is still maintained and kept in a functional state.

Well, you can argue that Murray Carter does act to preserve his razor/tool by doing the bare minimum necessary, but knife sharpening techniques in general tend to use up “extra” steel when sharpening simply because of the burr that is formed and then removed. But if you listen closely, Murray also says that he doesn’t always go back to the 1K each time. Believe it or not, I’ve even seen Brad, a renowned razor restorer, come under fire for his preservation methods from other restorers because he uses a buffer to remove rust and to polish the blades. You just can’t please some people!

This leads us into the most controversial area of Murray Carter’s method: Pressure.

Pressure

Techniques aside, pressure is a critical component of knife sharpening and razor honing. It’s one of those things  about sharpening and honing that is not easily conveyed, other than relatively subjective terms such as no pressure, light pressure, medium pressure, etc. As someone who straddles both knife sharpening and razor honing worlds, I can see from Murray’s videos that he is using a good deal more pressure on the razor than I do, and a lot more than what is generally promoted in the straight razor community.

I’ve often pondered why less pressure was better, when more pressure would arguably just get the job done faster. It is clear from the microscope pictures that with Carter’s method, some pressure isn’t all that bad. But what I’ve come to believe is taken from more from my experience with luthiers (violin makers) and their scrapers which are used to thin and even out certain areas of the violin (cabinet scrapers are a little different, being bigger, they generally use the corners and burrs on either side of the scraper ). In order to create the luthier’s scraper edge, it is sharpened, and then literally bent with a rod (burnished), creating a little “hook” or claw that scrapes the wood out. When it needs to be sharpened, everyone knows that you need to remove ALL the metal that was bent, or burnished, because it was stressed in the burnishing process and became too fatigued to hold an edge.

Go back to the straight razor, and we are dealing with metal much more fragile than the luthier’s scraper. I’m of the mind that pressure on the edge of the edge of the straight razor from repeated strokes causes the metal to fatigue enough to influence the integrity of the edge.

But the 1K Chosera picture from experiment really drives this theory home. I did back and forth strokes with knife pressure, which flexed the entire bevel – but I instinctively lessened the pressure as I made my final strokes, which allowed the bevel to “spring” back into a higher position, and the scratches only hit the edge of the edge and not the entire bevel.

Look at the picture again:

Boker - Chosera 1K Flex Variation

The angle of the scratches caused by the flex is shown by the longer vertical line, and reads 245.88 degrees. The smaller line is caused from the relaxing of the steel with less pressure, and reads 342.32 degrees – a difference of ~3.5 degrees in the scratch angles. It is not an anomaly in my honing technique, or caused by a stroke that careened out of control.

Now here’s the wrench – based on the Tornblom razor in the spine taping section above which took 3 layers of tape before it shaved well, we could argue that pressure on an edge that is too thin will remove the unnecessary metal partially through abrasion, and partially through what could be seen as self-regulation by the amount of flex the edge itself allows (within reasonable pressure limits – whatever that means!)

Of course, the razor community will argue that the bevel is the strongest and truest if less/no pressure is used, and it’s an argument I subscribe to – but I got you thinking, didn’t I?

Edge Trailing vs. Edge Leading

I don’t have much to say on this topic – Murray is correct about the surface of the stone, though. Here’s a picture of a 2K Shapton Pro stone at 400x. The white is the abrasive and resembles tiny craters.

2K Shapton Pro Surface

I don’t have a problem with edge trailing or leading, and I don’t think it is a huge deal in the razor community in general. However, I do prefer edge leading because the edge abrades against fresh abrasive and pushes the swarf and debris out of the way like a snowplow or bulldozer, and I personally think it leaves a more precise edge. With edge trailing, the edge may not get caught on the craters in the stone’s surface, but  it ends up running over all the swarf and debris.

Michiel Vanhoudt sent me a picture which showed edge trailing strokes from the Carter method on a 15K Shapton Pro, and in all honesty, I think it was more a cause of the pressure used rather than trailing or leading edge:

Edge Trailing, with Pressure

Michiel’s picture actually shows the edge of the edge being burnished, or pushed out of alignment from pressure. It is not a burr. If there were less or no pressure used, the edge would more than likely not be burnished, though.

Hanging Strop vs. Paddle Strop

Finally, we approach the final detail in this epic blog post: The use of hanging vs. paddle strops.

Murray advocates a paddle-like strop specifically so that the edge of the edge remains as true to being point at the top of a triangle, and does not round over, which, by definition, dulls the edge. However, leather is quite squishy, and compresses to round over the edge of the edge no matter how lightly you strop. Hanging strops don’t work to minimize that effect since they will droop more than a paddle strop.

Using either is acceptable for straight razors, but what’s most important is the use of clean leather before the shave. Let’s say you don’t have the fancy microscope pictures to help you, and your edge looks like Michiel’s picture with the burnished edge. That will be a harsh shave, for sure. Leather acts to caress, and in some situations the leather even abrades the metal ever so slightly, thus minimizing any burnishing.

In going back to precision that is offered by Shapton stones for example, the edge of the edge does become quite thin, and there seems to be some level of self-regulation of the edge of the edge with stropping – in other words, it takes the edge that is say .05 microns wide, and convexes it so that it is, say .10 microns wide – still within the limits of thin enough to cut hair, but with added strength and smoothness.

To touch briefly on edge trailing vs. leading again here is necessary – with edge trailing strokes on stones, I feel that the edge runs over the swarf and debris, but when stropping on clean leather, you must use edge trailing or you’ll cut your strop, but more importantly this is where Murray’s theory on stropping comes into better light- with a clean substrate, edge trailing will allow the edge to run over the bumps smoothly. Here’s a closeup of a bovine leather strop, courtesy of Michiel Vanhoudt:

Bovine Leather 400x

(Check out Michiel’s other microscope pictures of stropping substrates)

CONCLUSION

The first, and most important question is: Does Murray Carter’s method of razor sharpening work? The answer is clearly YES.

Is it the most desirable method? Well, as all most things related to sharpening, it depends If you want a quick and easy edge, yes, this method works, and produces a rather decent shave when you have an idea of what you’re trying to achieve at each level. With enough practice, it can be tweaked to a level that Murray Carter himself achieves.

There is a significant amount of wear that the razor will receive with this method, though, and here it depends on your stance – is it a tool to be used, or a 150 year old razor that you’d like to see have another 150+ years of  great shaves? For modern day production straights, such as Dovo and Boker, for example, they most certainly don’t “make  them like they used to,” and therefore, I can see using them up like tools. At the same time, some of the older razors were subjected to not-so-ideal treatment, and may take some serious restoration efforts to return them to shave ready condition, and once there, the idea of preserving the razor should be paramount.

It constantly amazes me just how much controversy is associated with sharpening techniques and it’s compounded when you add the politics of the straight razor world of honing. Hopefully some of the arguments presented will get people thinking about the bigger picture, and start people off on their own journeys to find out for themsleves.

It was a pleasure and an honor to be able to provide them!

I’d like to send out a special thank you to Mark Reich, Jens Skandevall, Michiel Vanhoudt, and Jason from Carter Cutlery.

Enjoy!

Nubatama finish

Nubatama stones are the newest playthings I’ve recently received from the US distributor, Ken Schwartz of Precise Sharpening. The main idea for me was to work with him to find a series of stones that we can add to the Edge Pro custom stone lineup, but that is another story for later I don’t anticipate carrying the whole line of these stones (I got 28 stones in 2 series in all to try out!) or know for sure if they will all make it to the US market. If they do make it you can be sure to find them at ChefKnivesToGo.com in Ken’s Corner.

As I stated, there are 28 stones within 2 series loosely grouped more or less by price into a “higher” Bamboo (竹) series and a “lower” Plum (梅) series.  There is absolutely no indication of a higher and lower quality reflected by the prices, though. The right stone for the job is clearly more dependent on the steel and style of the knife, not the series, which I quickly found out.

There are several overlapping grits, but they all have different properties, and it can drive a man mad trying to keep track!

Box-O-Nubatamas

Nubatamas - Left Bamboo series, Right Plum series

As luck would have it, one of the sushi shops I service called and the chef wanted me to fix up his Japanese Damascus yanagi. They usually have standard clad steel, so this one was more special than the usual no-name sushi knife most of the other chefs have.

Unfortunately, I didn’t get a before picture because I was just playing around with the stones to get a feel for them and didn’t realize it would lead to making a post about it so soon. As everyone knows, I am very much a Shapton man. I was going through every stone with a couple of different knives to get acclimated to they overall sense of how these stones would work, and ultimately compare to Shaptons.

Back to the knife – I started off with the 80 grit belt sander and then cleaned things up a little with the 240 belt. From here I played with the Plum and the Bamboo 180 grits. For this specific knife, I found the 180 Plum to be better suited for removing the belt scratches from the clad steel, although there wasn’t much for the stone to do here. I found that a slight trickle of water helped keep the stone working fast and refreshing the abrasive. There was no real slurry/paste forming. While the stone did release it’s abrasive, dishing was rather minimal. There is a solid feel, with a little cushion, similar to a Chosera, but with the aggression of a 180 grit.

180 Plum Nubatama

Next up was the Plum 320. The #320 Plum can be used without running water, and in fact, works better with just a light coating of water to keep everything wet. A little paste did form, and since I had done my initial shaping on the belts and 180 grit Plum, I was now set on cleaning up the scratches. Overall, this stone left an even 320 grit scratch pattern with a little bit of “graying” on the bevel that is indicative of a polish beginning to form.

#320 Plum Nubatama

Then I moved to the 400 Bamboo. Here’s where things got very interesting. On other stone series, such as  the Choseras, they begin at 400 grit. Well on the 400 Bamboo Nubatama, you must have your initial shaping finished already. This stone does not do any “work” as far as shaping is concerned – and believe me, I tried! You are officially polishing at this point.

A wonderful thing about the 400 Bamboo Nubatama is that it seems to know just how much abrasive to release to form a paste, while the stone itself is still quite solid underneath. I occasionally added a drop of water to keep the paste moving around. (I ended up coming back and spending a considerable amount of time on this stone in the end.) The end result was more graying of the bevel, but with still evident scratches, although they were not as deep (technique plays a role here, too. I purposely used the paste and did not try to use the stone.)

#400 Bamboo Nubatama

Next up was the #800 Bamboo Nubatama. Once again, while other stones are just beginning the sharpening process at this level, the Nubatama Bamboo 800 is polishing. And like the 400 Bamboo, the 800 seems to know just how much abrasive to release to form a paste. By the end of this stone, I had a clear, clean view of the Damascus pattern, and could see any imperfections and scratches I had missed on earlier grits. An interesting not here is that when wet, the contrast of the bevel was easily seen, but when the bevel was dry, there was more of a grainy gray finish and less contrast.

#800 Bamboo Nubatama

Then onto the #1200 Bamboo Nubatama. Once again, things got interesting. First of all, this stone has a serial number. That raised an eyebrow….. and on top of that, it looks like a big brick of dark chocolate.

This stone is much softer and a lot muddier – there is no grit release as much as there is mud release. Think of an Aoto, in fact I am calling it that. (sorry Ken) The end result was a smoother finish on the bevel, which enhanced the dry contrast of the Damascus pattern.

#1200 Bamboo Nubatama

The finish off the 1200 was probably “enough”, but hey, I got stones that go up to 10K! So the next stone is one of the most expensive stones in the bunch – the 2K Bamboo.

I must admit my Japanese Natural stone finish experience /aesthetic sharpening is zero so I don’t know what I was supposed to see on this stone, or if it was even meant for single bevels…but the stone was rather soft and chalky compared to the stones in both series up to this point.  Time will tell on this one. Obviously, there needs to be some more exploration with this stone to unlock its potential. Either way, it seemed to make the bevel smoother than the 1200, and seems to give more overall grayness to the entire bevel – both the soft and hard steels.

2K Bamboo Nubatama

Lastly, I used the 4K Bamboo Nubatama. Once again, something interesting happened. I usually sharpen the hollow ground side of a single bevel knife first, since the stone is at it flattest, and then do the bevel side. Well, I started with the hollow ground side, and it was terrible – nothing was happening and I was thinking this was not a stone for yanagis. So I flipped the knife over to be thorough, and suddenly, the softer damascus steel mixed with the stone and the stone instantly came alive!

That was cool.

4K Bamboo Nubatama

That’s where I stopped because of limitations to my time and the grit of the sushi shop

Thoughts and Conclusions

Everyone knows that Shapton sharpening stones are the standard by which I compare all other stones to, but the Nubatamas I tried for this review are the first stones to come around in a while that don’t try to necessarily compete in the same way (other stones in the pile do, though). There’s still a lot of work to do with learning about these stones, but the stones here are clearly more geared toward polishing and aesthetic sharpening, meaning you do your “work” at the lowest levels, and then work toward creating a beautiful finish.

These may even be a very real synthetic solution to using Japanese Natural stones, and are unlike other synthetics that try to produce aesthetic finishes that I have tried.

Once again, the money shot!

Thanks!

Basically, Sham claims that when finishing a straight razor on the 16K Shapton Glass, it causes microchips in the edge when more than 20 strokes are used. He has tried several approaches to the 16K, and all have failed him. You can read his complete thoughts about it, here on the Razor and Hone Forum.

I’ve known Sham long enough to know that as much as I don’t like it, he’s usually right. But being a die-hard Shapton fan, I naturally disagreed Besides, lots of people like, and some even rave about the edge off the 16K Shapton Glass. I’ve personally had many wonderful shaves off the 16K Glass.

So while Sham and I are arguing, people are somehow still somehow managing to shave. 

I feel that the majority of the problems anyone might have with the 16K Shapton Glass stems from underhoning, where the 16K scratches are revealing the bottom of deepest scratches which were not properly removed during earlier grits. (read my theory on razor overhoning). But this is Sham we’re talking about, and if you’ve ever shaved with a razor honed by him or spoken with him at length, you’ll know that he does know what he’s doing. So underhoning  is less likely the case here. Sham and I are also pretty much in agreement about underhoning, and he is of the mind that the use of diamonds in bevel setting process are the root of many of the problems experienced later.

Which brings the more technical possibility – the way the Shapton Glass series work. The Shapton Glass stones have a softer binder which allows for the more readily release of abrasive. They are designed this way to take on the harder and more abrasion resistant steels out there. In an all-Shapton Glass progression, it could very well be that loose abrasive may be causing little potholes, or microchips. Also, in conversations with Harrelson Stanley he has mentioned that the binder itself is a little harder on the 16K, which when it comes loose, may also get in there with the loose abrasive and swarf to cause microchipping. Keeping the stone clean is the best way to avoid this.

One of the reasons in my theory on overhoning is that the geometry may be too acute. With Shaptons in particular, they peel away the layers of steel at each level, gradually thinning out the edge of the edge on a razor. If that geometry is too acute for the steel’s characteristics, then it will break. A piece of tape or 2 to increase the angle is usually the remedy, and microchippng stops when the geometry is solid enough for the steel to hold that particular thinness at the edge.

So without further boring random facts, here’s what went down with the Tornblom on the microscopic level. All pictures are taken with a Veho-400x, and actual size is 1mm wide by .75mm high.

Before picture:

Klas Tornblom 185 - Before

There’s not much to say here, since the goal was to get this razor to 16K.There is some rounding of the edge of the edge, from stropping most likely, and the bluish streaks from left to right are oil residue.

1. Setting the bevel with a 1200 Atoma Diamond Plate

Klas Tormblom 185 - 1200 Atoma Diamond Plate

I generally always go straight to diamond plates when honing for others to make darn sure that any failures and successes can be attributed to my honing. Most razors do require the removal of fatigued metal or rounded over edges, and if it’s been sitting in a drawer or antique shop, then it’s safer to remove the top layers that may have been subject to oxidation. You can see that the edge of the edge is somewhat serrated, and eve a little flaky – but the bevel is set, and this does cut arm hair.

2. #320 Shapton Glass

Klas Tornblom 185 - #320 Shapton Glass

Here the edge of the edge actually looks worse than the 1200 Atoma, and that is true – the #320 Shapton is coarser. I used this stone to be sure that all the 1200 Atoma scratches were removed, and Shapton scratches were established.

3. #2K Shapton Glass

Klas Tornblom 185 - 2K Shapton Glass

I skipped to the 2K because my 1K was out on loan, so this experiment is already somewhat faulted. To make up for it, I spent extra time on the 2K, and this is about where it should be. The edge is only slightly serrated, but beginning to line up nicely. The 2K scratches are all lined up and a pretty even bevel surface is developing.

4. 3K Shapton Glass

Klas Tornblom 185 - 3K Shapton Glass

I love this stone! You can see just how much better the edge of the edge is lining up and how consistent the scratches on the bevel are.

5.  4K Shapton Glass

Klas Tornblom 185 - 4K Shapton Glass

Off the 4K Glass, the edge has lined up quite nicely, and there is a slight hint of a burr. I’m not worried about any slight burr at this point because my “critical leap”, which is the leap from abrading to polishing is going to happen between the 4K and 6K on the Shapton Glass stones.

6. 6K Shapton Glass – Gray

Klas Tornblom 185 - 6K Shapton Glass - Gray

You can see the transition from the duller bevel to the shinier, cleaner bevel of the 6K (my 6K white glass stone was also on loan with the 1K). If you look closely, you can already see some chipping/fraying at the edge of the edge. This will play a role later.

7.  8K Shapton Glass

Klas Tornblom 185 - 8K Shapton Glass

The 8K Glass starts to even out the bevel, and the edge of the edge is juuust holding up…

8a. 16K Shapton Glass – 10 Strokes

Klas Tornblom 185 - 16K Shapton Glass, 10 Strokes

With 10 strokes on the 16K Glass, the edge of the edge looks OK, and there is a minimal amount of fraying. With some stropping, this would be acceptable for shaving, IMO.

8b. 16K Shapton Glass – 25 Strokes

Klas Tornblom 185 - 16K Shapton Glass - 25 Strokes

Now is where Sham’s claims come to life – (remember – I said he was usually right) micro chipping and fraying appeared.Just to be sure it wasn’t an effect of hidden underhoning, I did 25 more strokes.

8c. 16K Shapton Glass – 50 Strokes

Klas Tornblom 185 - 16K Shapton Glass - 50 Strokes

25 more strokes did improve the overall edge, but you can see the edge of the edge has become too thin. I could also flex the entire bevel on my thumbnail, telling me that this geometry was too low. I actually stropped and shaved with this edge, and while it did shave smoothly, there was the “home alone” moment when I applied my Bay Rum. That completely confirmed that the edge didn’t hold up and I was dealing with a geometry issue. So I went back with some tape.

9. 16K Glass Stone – 1 layer of tape, 25 Strokes

Klas Tornblom 185 - 16K Glass 1 Layer of Tape, 25 Strokes

With 1 layer of electrical tape, I went back to the 8K Glass first, then onto the 16K for 25 strokes. A clear microbevel has formed, but the edge of the edge is still too weak. I tried 2 layers, but it looked the same as above, and I took a deep breath and added a 3rd layer and went back to the 4K Shapton Glass.

10. 4K Shapton Glass – 3 Layers of Tape

Klas Tornblom 185 - 4K Glass, 3 Layers of Tape

11. 8K Shapton Glass – 3 Layers of Tape

Klas Tornblom 185 - 8K Glass, 3 Layers of Tape

I know this looks worse than the original 8K picture, but you must allow me some wiggle room. 

12. 16K Shapton Glass – 3 Layers of Tape

Klas Tornblom 185 - 16K Glass, 3 Layers of Tape, 15 Strokes

Ok, so this does look worse, right? Well, yes and no. On my honing journey, I’ve been finding Swedish steel to be a little  funny (there are 8 more Swedes in the pile where this one came from). The steel is rather hard,thus on the brittle side, and will go to a point where nothing is happening, and then you suddenly have a microchip. If you look closely, there is actually no fraying of the edge at this point as seen in picture 8c above, yes there is some waviness in the edge of the edge, but it is clean.

13. Stropped and ready for the shave!

Klas Tornblom 185 - Stropped for the Shave

After 5 passes on my Kanayama 50,000 linen, and about 20 on the leather, this baby was ready for a test shave. The edge is thin, no doubt, and there are some teeth, but no real microchipping. The resulting shave was muuuuuch smoother than the initial test, and there was only a cooling feeling on my skin as the Bay Rum evaporated. With 2 full passes and some touching up, there was no burn at all. I even doused on a second helping of Rum

Conclusions

Microscope pictures are a helpful guide, but we can’t forget that anything that close looks ugly, and while I am a perfectionist, the trick is to know when to let certain imperfections go. That’s the hard part in this wonderful journey.

In the case of the Klas Tornblom 185 progression above, geometry was the key to preventing microchipping, but there was also the steel characteristics and the thin grind which, truth be told, I would’ve liked to put 1 more layer of tape on this razor. I was surprised at just how this the grind was on this razor, and how much effort it took to get her to shave well.

In regards to the 16K Shapton Glass chipping out, Sham is not entirely wrong – the edge will chip out if you do it “right”. Geometry plays a large role when using synthetic hones for razors, and the game is different than when using naturals.

Where Sham is spot on is the number of strokes on the 16K Glass (and 30K Glass for that matter) should be kept to a minimum – assuming underhoning isn’t an issue. When using an all-Shapton Glass progression, even I recommend people only do 10-15 strokes on the final stones. Keeping the stone’s surface clean is also essential.

The bottom line is that the 16K Shapton Glass IS suitable for getting a perfectly fine shave. And while the 16K Shapton Glass may be a little on the finicky side, the hone/stone is only one of many factors that combine together to influence the resulting shave.

Shave on!

I will say that the only major difference is that the Atoma is available in a standard EP size -  1″x6″ while the DMT is only available in the 2″x6″ size.  The standard 1″x6″ obviously makes things more consistent, but there are advantages to the 2″x6″ as well, especially with longer knives.

It is also quite obvious that the DMT diamonds are “sprinkled” into the matrix while the Atoma diamonds are precisely placed “clusters”. As with everything sharpening, arguments can be made for and against the merits of each, depending on specific situations. I will make my personal comments at the end of this post.

So on to the pictures

All photographs were taken with a Veho 400 USB microscope at 20x for macro and 400x for micro, and are approximately 13mm wide x 10mm high and 1mm x 1mm, respectively. The pictures have been re sized to fit the format on this blog, but no other alterations were made. Here are the links to the original photos for the Atoma and the DMT plates. All of the plates pictured are already broken in. Atoma does not have any official micron ratings as of this post, so all sizes are loosely compared to the JIS (Japanese) standard.

First up are the Atoma #140 and DMT Extra Coarse. These are not equivalent comparisons, as the the Extra Coarse is 60 microns or #220 grit, and the #140 Atoma is more closely related to the Extra-Extra Coarse (XXC) DMT, which is rated at 120 microns.  You can easily see the major size difference. Nonetheless, these two are the coarsest of the bunch available for the Edge Pro.

#140 Atoma Diamond Plate - Macro

Extra Coarse DMT Diamond Plate - Macro

#140 Atoma Diamond Plate - Micro

Extra Coarse DMT Diamond Plate - Micro

The Extra Coarse diamonds at the micro level almost look like pebbles on a beach in comparison to the giant, almost 1mm wide cluster of diamonds in the Atoma (don’t forget – the Atoma is rated much coarser than the Extra Coarse DMT).

Next are the Atoma 400 and the DMT Coarse. These two plates are more closely matched in terms of micron sizes with the DMT Coarse being 45 microns (#320 grit), and the #400 Atoma falling into the JIS 400 range, which is 40 microns.

#400 Atoma Diamond Plate - Macro

Coarse DMT Diamond Plate - Macro

#400 Atoma Diamond Plate - Micro

Coarse DMT Diamond Plate - Micro

The DMT coarse clearly has a more even coating than the Extra Coarse DMT, and the Atoma #400 cluster is roughly half the size and height of the #140.

Onto the Atoma #600 and DMT Fine. The DMT Fine is 25 microns while the JIS 600 puts the Atoma #600 at around 29 microns.

#600 Atoma Diamond Plate - Macro

Fine DMT Diamond Plate - Macro

#600 Atoma Diamond Plate - Micro

Fine DMT Diamond Plate - Micro

At this level, the Atoma #600 ‘s cluster seems to have reached it’s smallest width, and the DMT Fine has a dense, even coating of diamonds.

Lastly, is the Atoma #1200 and the DMT Extra Fine. The DMT is rated at 9 microns, while the JIS standard loosely puts the #1200 Atoma at 13 microns.

#1200 Atoma Diamond Plate - Macro

Extra Fine DMT Diamond Plate - Macro

#1200 Atoma Diamond Plate - Micro

Extra Fine DMT Diamond Plate - Micro

Personal Thoughts

As with all things sharpening, the answer to which is better is “it depends”. There is no doubt with my experiences that the DMT and Atoma diamond plates both deliver, they just do it differently.

The Atoma plates have a lot of positive things going for them: the #140 is certainly more aggressive than the Extra Coarse DMT, making it a better low end plate for profiling and chip removal. The systematic grid pattern of the Atoma plates make the diamonds less likely to “rip out” – for example, the knife may get between the spaces between diamonds on the DMT Extra Coarse. The Atoma plates also leave a very predictable scratch pattern at each level, which really appeals to my OCD and completely compliments the way my Shapton stones work. The clusters seem to ensure a longer lasting life of the plate, too.

But the Atoma plates come at a cost – literally. The labor in making the Atoma, while worth the cost IMO, may be a little over budget when compared to the price of the DMT plates.

Aside from the price factor, the DMT plates also have a larger surface area, which makes them better suited for working on longer knives, and even arguably faster since there are 2 inches worth of abrasives vs. 1 inch on the Atoma plates.  The sheer density of the diamond coating on the Fine and Extra Fine DMT plates leave a very even finish and “smooth” scratch pattern, as well, which makes progressing to the next stone level easy.

So once again, I recommend getting them all and trying them for yourself One thing is for certain in all this – I don’t see either series getting much rest between performances

The people in the following videos are actually all experienced straight razor shavers and are skilled razor honers who have all been deemed legally insane, crazy, unhinged, and even nuts by the highest authorities across several shaving communities. For more information about Maestro Wu’s knives, please visit maestrowu.de or jendeindustries.com.

I’m not sure how these videos ended up coming to be, but I think someone one the knife forums posted a video of himself dry shaving his goatee off with a 240mm kitchen knife, and someone said they could do that with a cleaver, and well, here we are 

The first video is of yours truly, Tom Blodgett, aka, jendeindustries. I’m using a Maestro Wu D-4 Cleaver that was honed using he Wicked Edge Precision Sharpener (WEPS) with  Shapton Pro stones up to 30K, finishing with Ken Schwartz’s .125 micron CBN (see my microscope progression of the honing process here). I have been shaving with straight razors for over 9 years, but only 1-2 times per week.

Next up is my good friend Michiel Vanhoudt of Belgium with his Maestro Wu D-11 Cleaver. He’s pretty new to the straight razor scene, but he is an extremely talented and experienced sharpener and fast becoming a major force in the straight razor honing world. I was secretly hoping he’d slice his head clean off, but alas, the only head that got sliced was that of a pimple on his chin.    His progression used the Edge Pro with custom cut  Shapton Pro #320, 1k Chosera,  then 2K, 5k, 8k, 15k Shapton Pros for the Edge Pro followed by 0.5 CBN, 0.5 CrO, 0.125 CrO, 0.125 CBN horse (all on balsa), and finally stropped with Clean horse from Hand American.

Next is my good friend Jens Skandevall from Sweden, aka, Honed and Bengt-Hans with his Maestro Wu Damascus D-11 Cleaver.  Jens probably has the most straight razor shaving experience out of the 3 of us. He free-hand sharpened his cleaver using full sized Shapton Pros 1.5K, 5K & 8K, then the Naniwa Superstone 10K . He finished by stropping with HandAmerican 0.50µ and .25µ Mono Diamond on leather, back to Hand American 0.5µ Chromium Oxide on balsa, then on to Ken Schwartz 0.1µ CBN on balsa & finally with Ken’s 0.025µ poly diamond on kangaroo. – Say that 5 times fast! This shave includes 2 parts below. Part 1 is With the Grain (WTG), and part 2 is Against the Grain (ATG).

AND Since someone is going to get the bright idea to attempt a large knife shave after watching these videos, please watch  this tutorial video I made about shaving using a Maestro Wu A-5 Damascus 10″ Chef Knife. I know the knives will be sharp, but it will hopefully save some of you crazy yahoos from lopping your head off because of poor shaving technique.  (BTW, the technique in the 3 videos above is all acceptable, it some of the others out there I’m referring to below.)

Enjoy!

Edit: Another video with a Maestro Wu D-11 has surfaced – this is the one and only Ken Schwartz of Precise Sharpening, and the granddaddy of the sub-micron CBN and poly diamond sprays out there on the market. This video is not for the faint of heart! (yes, he makes it out alive – but I don’t know how….)

As with all challenges, someone posted a video on the Knife Forums dry shaving his goatee with some kind of 240mm knife. Naturally, it brought out the freaks who enjoy shaving as well as sharpening, and the gauntlet was thrown down by I forget who at this point, and we ended up having 3 guys commit to doing shaves with their Maestro Wu Cleavers….

I decided I was going to hone my Maestro Wu D-4 Cleaver on my Wicked Edge Precision Sharpener (WEPS), and use this opportunity to document my Shapton Pro Stones for the WEPS. The main reason I chose the WEPS over free hand and even the Edge Pro was because of the clamped knife system, which reduces the amount of accumulated error due to flipping the blade that would need to be done on the Edge Pro or freehand.

One of the difficulties I knew I was going to face with a blade this big was the amount flex in the blade itself, being a good 3 inches (7-8cm) high and 1.8mm thick. On top of that, straight razors require a super-light touch, and I knew there would be some issue with how the paddles of the WEPS would create flex at the edge of the edge, which would normally not even be thought about if I were sharpening the knife as a cleaver.

But hey, if it were easy, everyone would do it!

This particular cleaver was a beater that had been experimented on several times, so I reset things on my belt sander before heading to the WEPS. I did not get a “before” picture, but below is a picture of a stock Maestro Wu edge taken from a D-6 Chef knife for another competition.

Maestro Wu D-6 Stock Edge (2.5mm wide x 1mm high)

Since I had already gotten the edge on the belt sander, I decided to begin with the stock 600 WEPS diamond plate set at 15 degrees on both sides. (I checked all my angles along the way with my Angle Cube. It’s a must for precision!) All microscope pictures from this point are 1mmx1mm.

Maestro Wu D-4 Cleaver with WEPS 600 Stock Diamond

I decided to do my normal progression of Shapton stones that I would do on straight razors. Looking back, I should’ve gone to the #320 Shapton after the #600 WEPS to really clean things up since I normally go to #1200 on diamonds – I actually don’t have them for the WEPS, though  :/

But I do know what I’m doing, and I went to the 1K Shapton Pro from the WEPS 600, which as you can see, is perfectly fine.

Maestro Wu D-4 Cleaver WEPS 1K Shapton Pro

Then onto the Shapton #1,500. I really like this stone because the 1K Shapton is on the coarser side of things, and the #1,500 really helps clean things even more before the critical leap to 5K, where all of the previous shortcomings are revealed.

Maestro Wu D-4 Cleaver WEPS #1,500 Shapton Pro

You’ll notice there is the slightest wave at the edge of the edge  t is at this point where I was beginning the think that 15 degrees was going to be too shallow. Most straight razors are between about 18-21 degrees.

I moved on to the Shapton Pro 2K stone and saw that the edge was crumbling a little – mostly due to my lack of razor honing technique on the WEPS – so I upped the angle to 18 degrees. You can see the new angle in the first picture below, and then the finished 2K.

Maestro Wu D-4 Cleaver WEPS 2K Shapton Pro - transition to 18 degrees

Maestro WU D-4 Cleaver WEPS 2K Shapton Pro - Finshed 18 degrees

The finished 2K shows evidence of a burr, but up until this point, that is acceptable in my mind, given the circumstances and dimensions of the knife!

On to the 5K – the 2K-5K is the critical leap, and I spent a good deal more time perfecting my 5K edge than any other. It is the key to success with the Shapton Pros.

Maestro Wu D-4 Cleaver WEPS 5K Shapton Pro

At this point, picture taking becomes more difficult with the added frailty of the edge being likely to chip from hitting the scope!  If I were sharpening this cleaver as a regular cleaver, this is where I would normally stop on the Shapton Pros. However, for a straight razor shave, it is not good enough yet!

On to the 8K. Having done my preliminary polishing on the 5K, the rest of the stones move pretty quickly to further polish.

Maestro Wu D-4 Cleaver WEPS 8K Shapton Pro

You can see how thin the edge of the edge is becoming – there is some evidence of rolling at the edge of the edge – again, from my technique and the way the stones do need to push against the steel. In fact, you can see from the slight angle change that I did put some pressure on the edge.

Maestro Wu D-4 Cleaver WEPS 15K Shapton Pro

However, on the 15K I used as little pressure as possible, and the edge becomes very crisp and clean. The shine from the reflection of light was becoming a hassle for the pictures! This would be a comfortable shave by normal standards, but Shapton goes to 30K.

Maestro Wu D-4 Cleaver WEPS 30K Shapton Pro

I will admit I did something I shouldn’t have done, which is more strokes than normal at this stage. The clumping on the bevel is evidence of elements of the swarf. I normally only do 10-20 strokes, but It felt so good, that I did about 50, and the water on the stone dried out.

I wasn’t worried because I knew I was going to use Ken Schwartz’s .125 Micron CBN (available from Wicked Edge here), and that there was going to be some convexing of the edge of the edge due to the leather paddles.

Maestro Wu D-4 Cleaver WEPS/Schwartz .125 micron CBN

The CBN really cleaned things up for the plain leather WEPS strop.

Maestro Wu D-4 Cleaver WEPS Plain Leather

As you can see from the plain leather paddle, there is some rounding of the edge of the edge. This is not always bad for shaving The weakest, thinnest portion of the edge is gone, leaving a solid enough width at the edge for shaving. You can see a fresh score going in the opposite direction of the normal scratches – this is from contamination, most likely from me when wiping the blade down with a tissue with my dirty hands…

The overall shave was a success. There are 3 guys in on the “competition”, and I will post all 3 videos when they come out. In the mean time, here’s my picture of the Shave of the Day. Enjoy!

SOTD 9/12/2011

The next problem with the theory of overhoning is a little more complicated. That is the part that says that an edge is and/or can be  “too refined”.

The way I see it, any given stone will only “allow” an edge to be as thin or as thick as the height and depth that the abrasives can cut. For example, an 8K edge will only ever be as thin as the depth of the scratches made by the 8K abrasive. If it is too thin, then the 8K abrasive will cut through the steel. 16K should theoretically allow for the edge to be half as wide as the 8K, and so on. In this view, overhoning is technically  impossible because the edge is continually renewed at a constant thickness.

When honing razors, the overall agreed upon minimum refinement for a razor is 8K or abrasives as small as about 2 microns. It is 8K because this is the level at which the edge of the edge becomes thin enough to comfortably sever the hairs on your face 6-7 days a week, but thick enough to hold up to 5-6 shaves in between touch ups.

This has led to a rise in the belief that if the edge becomes too refined, it  will be too weak to hold up to a shave, or it’s lifespan will be greatly reduced. The more recent upper limit was .25 micron in refinement, or about 60K. This idea has been challenged since the first .125 Micron CBN (that’s 120K) edges started coming out. (Here’s a review of one of the first documented .125 micron CBN edges from 12/2010) We have since moved on to .1 micron (150K) and even into 50 and 25 nanometer edges (.050 and .025 microns or 300K and 600K, respectively!).

It is without a doubt that more refinement does yield a closer shave (whether or not it is smoother and/or sharper is another topic entirely ).  But there is a tradeoff that must be acknowledged as refinement increases – the edge of the edge becomes thinner as it becomes more refined, thus inherently more fragile. (It certainly cuts through hair much better, though!) So can be seen as true that an edge with more refinement will not hold up as long as one with less refinement. However, it can also be said that a closer shave lasts longer than one that’s not as close. But in terms of overhoning, the abrasive’s characteristics determine the thickness of the edge. The rest is reliant upon the steel quality and geometry. Good technique doesn’t hurt, either!

Bart Torfs, who is probably the the world’s leading authority on Coticules, summed up on a B&B thread what I am thinking much better than I can:

This pretty much concurs with what I always assumed to be going on with small chips that can be seen under magnification immediately after honing. They are just the deepest remnants of a saw tooth pattern left by the coarser stages of bevel formation.
“Overhoning” by the definition of an edge disintegrating once it is supposedly taken beyond the keenness limit of a particular hone, is a hoax.
If the blade in the picture is honed further on the stone it was finished with, there will be no new chips to form. Quite the contrary: more metal will be removed and the boundry that forms the very edge will slowly shift towards the bottom of the chips. The finishing hone may be too slow to “hone the chips out” within a reasonable time frame, but that is what eventually would happen.
There is no single physical reason why a hone could abrade “through” the bevel. In fact, the hone only “abraded through” the steel at the very apex of the bevel. It leaves a particular type of edge jaggedness akin to that particular type of hone. The only reason why there could ever fall fragments out of the bevel, that are larger than a hone’s normal abrasion, is when there is structural damage in the steel, caused by corrosion or stresses induced by erroneous tempering.

So in the end, one must choose for themselves – just be sure not to overhone your edge!

As the host and honorary judge of this competition, I supplied 7″ Maestro Wu Bombshell Steel Chef Knives to the participants, without knowing who got which knife. I knew there would be no clear winner, and my main goal was to make this a learning project. And learn I did. The knives were all amazingly sharp and well done.

I took microscope pictures of before and after the cutting tests – and it is from these pictures that this blog post is based to support my theories on Overhoning straight razors. I know these aren’t straight razors, but the similarities to what I saw on straights when I honed and on what I saw on these knives sharpened by others gave some quantitative support to my long lingering theories. Besides, the guys sharpening were no hacks, and approached their sharpening in a similar fashion to straight razor honers.

All pictures here were taken with a Veho 200x USB microscope. Original resolution size is 1mm high x 2.5mm wide.

OVERHONING

Overhoning is a controversial topic amongst straight razor honers. Most people who know me know that I respectfully do not subscribe to the theory, which basically states that too many strokes on a hone will cause the edge to become a “foil edge”, which is too thin to support itself and folds over during the shave; and/or cause microchipping in the final, and most delicate stages of razor honing.

As far as foil edges on straight razors caused by overhoning, the thickness of the spine of the razor combined with the width of the blade determines the edge angle. Since we hone razors with the spine flat on the stones or strops, the geometry is predetermined. If the edge angle should be too low and the steel quality isn’t able to support such an angle, it will fold or break. This isn’t  a direct consequence of overhoning, as in too many strokes. It’s clearly one of geometry. Increasing the angle by adding a layer of tape will reinforce the geometry, thus stopping the breakdown or foiling when honing.

Once geometry is accounted for, one can arguably hone past the point of ideal or what is considered “enough” – in other words, “overhone” in the sense that you took more passes on the hone than was necessary. However, this shouldn’t raise a burr (with single side passes as in straight razor honing) but will continue to reinforce the geometry that is there. In an example taken from knife sharpening, where a burr is often formed and is the indicator for “sharp” on one side, it clearly is honed passed the point of “ideal”, but there is no foiling of the edge once the burr has been removed (unless the angle is too acute). The same applies to razors. Once you get “there” you will only continue to reinforce that angle. Of course, the idea is to know when to stop, but that is another issue (I’m not addressing the spine wear issue here) 

That brings us to the argument of  microchipping as a result of overhoning. It has long been my belief that what really happens is that each successive level of refinement ultimately exposes ever deeper scratches left behind from earlier stages as it establishes it’s own scratches. In fact, it’s not that the edge actually chips, it’s that the edge is refined enough with smaller scratches around it to reveal the gap left by the deeper scratch!

Below is a perfect example – the vertical deeper scratches lead directly to a microchip in the polished edge.

Microchip 1 (200x)

However, microchipping at the finishing stages is a real phenominon, as anyone who has honed a razor has probably seen the semi-circular chip-out just left of center, below:

Common Straight Razor Microchip (200x)

This micro chip, and the triangular one to the right are often attributed to overhoning because these chips only appear at the final stages of honing. While I said before that the microchipping were preexisting gaps that become exposed, it could also be that because the scratches are so relatively deep, by the time  the razor is honed to such a thin and even plane at the edge, a preexisting deeper scratch causes the chipout due to lack of support from the steel around it – a weak link, if you will.

Let’s take a closer look at that microchip and how it most likely formed:

Microchipping closeup (200x enlarged and cropped)

If you follow the chip upwards from the edge, a deeper scratch is revealed in the bevel, as marked by the arrows. In other words, the deepest scratches from a coarser stone/belt/diamond plate had not yet been completely removed and only when the edge becomes thin enough so one can shave with it does the earlier damage become apparent.

At this point, an argument for the theory of underhoning  – not overhoning – can be made.

Something to think about

In Part 2 I will discuss my theories on overhoning in regards to edges that are deemed “too refined”.

He gives me a nice plug, too – not to mention a jaw dropping knife demo… (and I’m no easy pushover when it comes to knife demos)

Thanks for a great video, Clay!