Did you see it? He and a buddy apparently tested a whole bunch of sharpening methods using some sort of expensive sharpnes-testing device. Claims nothing is sponsored, but he seems to be pushing the scary sharp method using sandpaper on a flat surface ( that he sells). Two big takeaways were: (1) stropping on a HARD leather surface is critical, and (2) Shapton stones are worthless.
I'm bothered because I just purchased a 16,000 grit Shapton stone! Now I'm wondering if I threw away my money.
I have not used any stones over 3000 grit or scary sharp, and have never heard of Katz Moses. But I've somehow gotten by for 50 years of woodworking without.
To be blunt......in the pantheon of woodworking gurus who are worth listening to because of their vast experience and expertise in making fine furniture.....Katz-Moses ain't on the list.
A Shapton 16,000 grit stone is a very high-end piece of kit. But, a very effective and useful cutting edge can be practically obtained well before reaching the 16,000 grit level. You have not wasted your money......I know that Rob Cosman uses this stone in his sharpening regiment......so enjoy it......but, more than anything, use it......form your own opinion based on your own experience.
Develop a sharpening system......a sharpening regiment......that works for you......and then perfect it.....get good at it......over time you will know what is working well and what areas need improvement.......don't listen to every wannabe that comes along trying to sell you something.
Yes, that's it. I more or less had in my head what Roger said here and will no doubt go along with his advice. But I did find this KM video informative. Just the information about the leather and MDF is useful, if true. Regardless of KM's reputation, one can see that the two of them did indeed do a lot of testing. And whats up with that sharpness meter? Does it really work? Since you have seen the video, what do you make of it?
As I recall, what the two presenters were saying is that there is a rule of diminishing returns. The 16K Shapton produced a good edge, but the 30K Shapton was not significantly better. That was their conclusion.
The thing is that they strop on green compound (60K), and believe that anything else is just leading up to this.
They make a good point here since stropping is a way to remove the wire, and you cannot have a sharp edge with wire attached.
Years ago I did similar blade testing using a sharpness tester that cut loops of thread, and also examined edges under a digital microscope. The first thing I noticed was that the results varied considerably depending on the way I set up the sharpness tester. My results using a tensioned thread (like the setup in the video) didn't seem to be reliable, based on comparing them to other methods such as shaving arm hair or slicing paper. Repeated tests of the same edge produced numbers that varied more than the differences between edges sharpened on different stones. The pre-tensioned threads used in the video may solve that problem but I'd still like to know the variation when the same edge was tested multiple times instead of just once. I ended up testing each edge ten times or more and averaging the results.
The method recommended in the video is to sharpen to about 1000 grit (15 microns or so) and then strop using hard leather charged with compound. The stropping will remove the wire edge and create a slightly rounded, much more finely polished cutting edge. This isn't a bad way to sharpen but it doesn't produce the best edges, either. My biggest objection that there is probably damage to the steel below the surface that will decrease edge life. When I sharpen I like to stop grinding before I reach the edge and use 3 micron or finer abrasives to do the last little bit.
The 30,000 grit Shapton stone they describe as "terrible" is one I tried out in a class given by Harrelson Stanley. It worked well and produced a very sharp edge, comparable to the edges I'd achieved using 1/2 and 1/4 micron diamond paste. That's way sharper than I aim for when I'm just building stuff instead of testing sharpness.
Katz-Moses uses a trailing stroke only (pulling the blade toward him instead of pushing it too) which tends to let the wire edge build up. I found that my edges tested sharper when I did the last dozen or so strokes by pushing the blade, which removes almost all the wire edge when using very fine stones. This reduces the need for stropping. His assistant in the video uses a forward-and-back technique and achieves better sharpness using the same test machine. (I watched his video, too.)
The fact that Katz-Moses found no difference in sharpness between 25 degree edges and 30 degree ones tells me his testing method was not very precise. I found a consistent correlation between more acute angles and higher sharpness. The downside of more acute angles is that they chip or roll when used in planing. I wouldn't go lower than 30 degrees in a plane blade with any of the steels I tested.
The video's title "The Most Comprehensive Sharpening Test Ever Done" is hype, but then it's on YouTube so that's what I expect. I don't think the guy is dishonest but his tests are not as conclusive as he claims.
It is not my intension to put Katz-Moses down......he is a young man trying to make a living.....trying to build a business which is the basis of our economic system......so when you watch him, remember that. It was a good video......lots of information on sharpening.......but, the conclusion is aimed at favoring products that he happens to sell.
Numerous times during the video, KM states that it does not make a difference which system you use (water stones, diamond plates, or sand paper sheets)......all will produce a sharp edge.....as long as you strop at the end. I use water stones......but, I have a wet sink in my basement shop that allows me to contain all the mess of water stones and flattening of those stones etc etc......without that, I don't think I'd be recommending water stones. And that is what KM is doing.......he's recommending (selling) sand paper sheets that can make a sharpening system with less of a mess. No information on the economics of using these sheets.....how long they last......how often you will tear one and have to replace it......etc etc.
Interestingly, KM openly admits that even if you sharpen below the arbitrary level of 140 on their sharpening device......a little use of the tool will result in the blade settling in at 150 or so on their scale where you will continue to work for a period before the tool dulls noticeably. This is what Derek is pointing out as "diminishing returns" of sharpening to very fine grits which result in tools that will only remain at that level of sharpness for a very short time when the tool is put to work. So, the question is......is it worth all the cost and effort to sharpen to the extreme??
Eliot....I think you should use your 16,000 Shapton just as Rob Cosman does.......when he's working and notices his blade isn't performing as he likes.....he sharpens the micro bevel on his 16,000 (I'd use a guide).....removes the burr (maybe better done on a hard strop)......and goes back to work......remembering, of course, he sells that stone.
One factor that came out of that video for me was a reminder of the value in stropping to ensure the wire is removed.
It is possible to prevent the incursion of a wire simply by raising a small wire with each succeeding stone, and finishing on a high grit. This will reduce the wire size progressively. However, there is still wire remaining. Final stropping on a hand is a time established method, but a leather or wooden strop is more reliable.
I used a Hard Butt leather strop, either plain leather or green compound (I have both), for years and then switched to green compound on planed hardwood. The leather has a smidgeon of compression while the hardwood has none. I also have a piece of MDF which has been used successfully (unlike the comments in the video). It needs to be noted that my MDF is well-used and saturated in green compound.
I like the harder surface as dubbing is avoided, yet the leather gives the impression of a sharper edge. After the video, I cleaned up my leather strops (with a scraper) and will try them again.
I stroke both the bevel and back on each stone as I progress. I check for a wire on my thumb nail and I guarantee that there is no wire when I'm done. The final test is to shave my arm. If there was a wire, it would not shave. But what do I know, I'm not on YouTube and I'm not popular.
Quit watching videos by people monetizing their YouTube presence and selling something via those videos.
You can produce edges suitable for woodworking with nothing more than a fine India and a charged strop - about $30 worth of "kit." You don't actually have to have a grinder, but if you do decide to hollow grind you don't need anything more than a basic 6" grinder that costs around $50. The wheel that comes with the grinder is fine. It'll remove metal. That's all you need it to do.
I found the video informative. Is he selling something? Sure. This is how he makes his living and pays the bills for his family. He makes very professional instructional videos, sometimes with subtle hooks to his line of premium woodworking tools he has designed.
For someone like me, who knows almost nothing about woodworking, I find them very well done, almost like having a shop instructor walk me through the detailed steps of doing something, with great camera work, where at the end I feel I could actually do exactly what was shown and described. I see some criticism about him not actually making anything, but to me that is not the point. The purpose of an instructional video should be to show the process, not the end result, unless the purpose is to inflate the maker's ego.
I am not the one who said that I'm not aware of any finished pieces made by KM. In fact, I'm not, but I'm not the one who said it here. I have seen videos of him cutting rather elaborate tiger tooth dovetails and similar joinery. I believe he is a fine woodworker of sorts. And I see clearly his approach to selling his goods in the business that he has chosen for himself. There's nothing really wrong with that. I learned a few things from his videos.
The bottom line for me is that I will continue to sharpen more or less the way I have been doing it. But I will keep my brand new 16,000 Shapton and will fool around with different stropping leathers and compounds to see how they work. And I'm not about to buy a sharpness tester; I can see what's going on when I plane some wood.
BTW, his sandpaper on tile approach is probably not a bad idea. But good sandpaper is not cheap.
I do agree that stropping isn't essential (nothing really is), but technically it will still shave with a wire. Happens if a wire edge was too fat, then it can leave a very minuscule wire edge, which will be soft and bendy, but it will shave. Thought of course you would figure it quickly since a cutting edge would deteriorate very fast. Also it would shave say bevel up, but wouldn't shave with bevel down, this is also an indication some false edge is still there.
But yeah, the type of abrasive doesn't matter, only removing the wire completely. I can get an edge that shaves from a fine India. It will shave, but the surface quality wouldn't be great and edge life isn't going to be long. Soft Arkansas gives a shaving edge all the time. I strop, though not for sharpness, but for longevity. David W posted a bunch of microscope photos, basically an edge can be sharp but ragged, and in such a case damage tends to propagate deeper into the steel, so it dulls faster. There's a bunch of variables to this equation, softer steels seem to be more prone to that, harder steels might form almost no wire edge at all, but there's no reason why something like water stones or ultra-fine diamonds, or any other abrasive close to 0.5µm wouldn't remove a wire edge completely.
So he's cut some trial joints? I didn't search extensively, but I can't find a piece of furniture or general woodworking he's done. I'm sure he has, I'm sure it's fine enough.
Trial joints are a nice parlor trick. I have no wish to change anyone's sharpening routine. I also prefer to avoid infomercials.
I've never used a 16,000 grit Shapton. I have no idea how this grades out vs. some sort of standard, but clearly it's a very fine stone and my guess is that you'd have more to lose by stropping than gain by stropping. I have used abrasives on glass in the past and there was no need to strop after finishing on 2,500 grit wet/dry, especially if the compound is not very tightly graded and controlled. If you're looking for extremely fine media, graded and produced to a high standard then look for optical polishes -- the kind used on multimillion dollar instruments. The green wax stick is a joke.
I don't know much about the thread-based sharpness testing device, but it seems very far removed from the actual action of cutting wood. A youtuber did a chisel test some time ago using the a similar device.
I find test results produced with a CATRA device a lot more informative. If interested, check this article by Larrin Thomas.
