OK, I’m confused. You said it was true and used that to ask why it wasn’t that way in the UK and US. You then go on to say it’s because the Europeans found a better way. Are you now saying we don’t know if that is true? If we don’t know that that is how almost all European blades were ground how can we say they found it to be superior? Just trying to follow the logic Help me out, like I said, I’m confused
Some old German books say "it's a more advantageous way of honing." What does that mean to you? I find it vague and puzzling, and could cover so very many things.
you gave up questioning You are literally promoting a technique that you have never even tried… Arguing with somebody that that has tried it and just about every other “new” idea that people have presented over the last 17 years of honing professionally.. It isn’t that I know i’am right in theory, or parroting somebody else, I know I am right because I have done it If I hadn’t, then I would try it, and test it on 50 different razors sending them out after a test shave and see how many WOW responses I get back.. I don’t even talk about a technique or new Hone/ Stone until I have tested it on 50 different razors.. Yet here you are with zero experience telling us all about how great it is That isn’t questioning… honestly I think that is what bugs me about this thread the most..
I told everyone in this thread that I was still researching this. You came here with a lot of questions, that you demanded answers to. So I gave them to the best of my ability. You asked me to list the advantages, so I gave you those as best I knew them to be based on the science behind the theory. We both know you've forgotten more about honing razors than I will probably ever learn. I didn't ask to have this discussion at this time. I said I wasn't ready to discuss it, precisely because I wished to continue to learn more about it. You asked me to present the argument for convex hones. I did the best I could, despite my complete lack of preparedness and uncertainty in the principle. I haven't even shaved with a convex honed razor. I would have at liked to have done that at least a few times before having this discussion. Go back and re-read what I posted before you jumped in with your questions. I am not your enemy. In case you haven't noticed, I'm also in the "oh so popular" club of people Jarrod likes to make fun of on YouTube. What reason would I have to promote something I don't yet understand fully? "That isn't questioning." Then what is it? I concede the argument. Razors honed on flat rocks shave just as good as ones honed on bumpy rocks. You win. Your experience is vast compared to mine. Which is, last I checked, zero, when it comes to convex honed razors. That's probably what's bothering you about this thread. It's like dueling a cripple. The other problem you're having with it is you probably haven't had this discussion with anyone who likes and respects you. You know I generally don't like to post stuff until I have it well sorted out to my personal satisfaction, and this isn't the usual high caliber grade stuff I post. You've seldom, if ever, seen me post so many maybe's, possibly's, and I don't know's in one place before, when talking about a deep subject.
Why not just thin the spine? That will widen and thin the bevel too, and you can still use a flat hone.
Yes, there is no reason why you could not do this. However, you will be loosing some of the width of the spine. If you create a bevel angle that will not hold, you are not able to put steel back. You are then forced to add tape on the razor, or grind off more steel on the blade to get a workable bevel angle. The steel needs a minimum amount of stiffness to effectively be cut. By moving the abrasive field resultant closer to the apex makes it easier to refine the edge as the edge gets more refined, and more flexible (maybe to flexible to be cut with a certain abrasive). The steel removal is proportional to the effective force over an area. When the force resultant is acting closer to the back of the bevel, the material is not removed evenly over the bevel plane. This might contribute to burr formation, and problems "cleaning up" the edge. Slurry on natural stones, like JNAT's also does some of the same thing. The slurry directs more of the abrasion closer to the edge. It also creates some minor convexity behind the edge. You can do the same with a narrow hone only shaped over the short axis, by using a fixed skew angle to cut in a new bevel, and make it longer. Standard flat bevel Concave bevel used on a flat stone to refine the cutting part of the bevel plane, and apex.
Honing with a skew angle over a narrow stone, that is only curved in one direction, has some of the same effects as a convex stone. This will act like a honing rod. When the skew angle is 90 deg, the stone will have contact over the whole bevel plane, and on the spine (which technically also is part of the bevel). If you use a skew angle, you no longer have contact with the whole bevel plane. The razor will be resting on the bevel shoulder, and on the spine. As you start to remove material you will grind in a taller bevel, and accomplish some of the same things as a convex stone, just without the small concavity, which is really not that important in itself. It actually works quite well. I used a narrow coticule shaped this way, with slurry to cut in a new bevel. Then i finished on a full sized fine flat coticule with just water. By doing this you can work quite fast, even with relatively slow stones. You can also hone problematic razors much easier, if you avoid having the geometry fight you through all the steps. As you can see this also creates a gap to the flat stone. This will help to even out some of the imperfections of the razor. You will get a good undercut when you move to your finishing stone. The finishing stone will also in this case be working over a much smaller surface are closer to the edge, and thus make it much more efficient. Everyone who have a stone that is thick enough (20 mm for instance) can try this, without having to compromise any of the stones for normal use. This type of application would have been quite relevant for people in history who probably had limited access to the stones we use today. If they only had a few natural stones, making them work more effective would have been a priority. It was not my intention to derail the subject. However, since this is quite comparable to what is effectively also going on when you use a convex stone. The contact points over a convex surface should stay fairly perpendicular, but because the radius over the diagonal of the stone is different, when you are at a skew angle of 90 deg, some of the (in addition to the aforementioned effects) will be going on.
What this all boils down to is: 1. Several here have honed a lot of Straights. All makes, models, issues, quality, and types of steel. 2. The wider(larger), the bevel. Which translates to a thinner piece of steel at the bevel end, is usually not a good thing. 3. Thinner hard steel has a propensity to break apart(chippy edge). Not a good thing. 4. Most, if not all of the better honed razors have a smaller bevel. All due to an increase in spine thickness. Usually a well made razor, when new, will have a small bevel. The more it is honed, the larger the bevel gets, usually, due to poor honing techniques. Tape counters worn spines, and large bevels. 4.5. Convex hones thin the steel out, leading to the issue listed above. 5. Convex hones lead to a smaller area that the blade can touch stone. Hence issues I've seen with the heel end of razors honed on Convex stones. As well as issues being reported by others who extolled the virtues of Convex Hones. People can theorize about which ways of honing, until "The Cows Come Home", and even mathematically try prove their theories. But, none of this theorizing matters, unless you can replicate it with facts(cold steel and stones). I say all this with respect. I am still willing to test one of @PLANofMAN 's Convex Hones, whenever they get built. I dont know what else can be said. .
Part of the motivation for me to start exploring this concept of convex honing was mostly for coticule honing. I had one hard and fine coticule and one coarse. The coarse one i would not call a good finishing stone. From my experiance the best coticule edges i got was from using slurry that was thinned to clear water. The problem with coticules is that the garnets do not brake down. It can be difficult to make up for the apex dulling effect caused by the slurry with a hard, slow, but fine finishing stone. By playing around with the geometry of the stones, i was able to get an ok edge to a better edge with the stones i had. Staying for too long on a cotiule with wather or oil usually resulted in the edge going backward at some stage. I wanted to limit this by needing to stay on the stone for a shorter time. I liked the idea of sticking to what i interpreted as an old honing style that had been used by most of the German and French razor manufacturers to this day. In my opinion, the holy grail of razor honing is understanding what is going on at the apex. I.e. the fingerprint every type of honing procedure leaves. At the end of the day, if the stars aligns, the difference is really not that big, and for allot of users, especially without heavy growth do not matter that much at all.
@JPO - in this image it appears that the shoulder of the bevel is not on the hone (gap). Is the hone hitting the blade above the bevel? The lower profile of the blade is not shown. And since the force is at the apex, won’t the apex of the edge quickly wear away where the shoulder will be hitting the hone?
In this case the spine and the front part of the edge will be hitting the stone. Yes, if you are moving to a fast flat finishing stone the tip will just wear away, and you get contact with the bevel shoulder again. Here is where a hard stone like an Arkansas can really be good, bacuse of how slow it cuts and the hardness. If you move to a jnat with slurry, some of the slurry gets trapped in that concavity, and seem to be able to maintain this shape better. I just know it works quite well. In reality I the the gap will not be there, or be really small because the bevel will flex, but you are able to move your resultant reaction closer to the apex. This will initially also help to even out small geometry issues. As you move to a flat finisher the razor feels different on the stone compared to a flat bevel. The undercut is better, for what that is worth
See this “Slurry on natural stones, like JNAT's also does some of the same thing. The slurry directs more of the abrasion closer to the edge. It also creates some minor convexity behind the edge.” This is a theory it is not proved, I happen to believe it but would never claim it as a fact. Over thousands of razors honed and sent back to customers I have received many WOW responses from using variations of this to finish on almost every finisher including some Synth Hones Not a fact.. Fact: Of you remove steel from behind the Fin /Apex of the edge you WEAKEN the edge Fact: The strongest longest lasting bevel shape is a Convexed or Almond This is proved on Tools Knives and Razors People used many specialized grinds for a specific purpose but that fact hasn’t changed When you claim a “More Flexible” edge it also means a weaker edge by very definition Same as the actual grind of the razor, a Near Wedge is by very definition a stronger razor than a Double Hollow @PLANofMAN Let’s be factual here You have changed the very definitions of the Bumpy Hone claims not only in this thread but since Jarrod and Bill promoted it here Beginners vs Advanced Easier vs Difficult I also see that this is now being presented as a Finishing Technique aka Micro-Beveling after one creates a true bevel I actually like to see that change, it becomes more plausible as such Micro-Beveling is easier to accomplish and test.. To be honest I have always doubted most people’s ability to even hone steady enough to create a Concave bevel.. Especially to create and hold one through low or mid level hones.. Just so you know, trying to prove a honing technique through math presentations means little to nothing Your hands the razors and the hones themselves are not exact enough to attain the sub-micron calculations. I seriously doubt many of the “Concave” edges get past the first round of stropping on Linen.. I never checked when I tested this technique, probably should have.. Now go get some steel on the stonesv Hone On !!!
Yeah, normal people can’t do this, lol. Some ‘peripheral’ observations: I think razor bevels flex more than most of us think that they do. If you have a JNat (because it makes a hazy finish on slurry), try the usual back and forth strokes with normal finishing pressure, then look at the bevel finish with a loupe - you need to see the entire bevel. Now, go back on the same stone/slurry with very light, feather weight strokes and do 20-30. When you look at the bevel, you will see a bright area at the apex, but not further up the shoulder. Alex Gilmore also told me that circles/ellipses polish the entire bevel, but straight strokes hit more toward the apex. He is correct.
Here is how a concave bevel acts when it is honed on a flat jnat with slurry. The action from the slurry is focused on the middle of the bevel, and towards the apex. The upper part of the bevel is hardly affected. One or two strokes on something like a 30k will show the apex convexity caused by the slurry. However, I think this effect is quite visible even on the hazy finish.
You’ll get an almost identical image on a flat bevel with a JNat and slurry. This is one of my edges, scoped by Jerry King (I don’t use a microscope). The image is from a razor that I honed for him on a flat JNat. See the similarity?
I agree. You can even manage to create a concave bevel just by using a diminishing pressure. Finishing with feather light strokes, like you probably have used. This utilises the same principles, if done right. Shoulderless blades makes this easier, because you don't need to take into account the extra stiffness close to the stabilizer. However, you are more likely to digg into the stone more with heavier pressure at lower grits. Which makes this difficult to pull off, but possible.
Ha ha, you are correct, diminishing pressure, or at least different pressure at different stages, and feather weight finishing strokes.
Not all stones allow you to pull it off. A jnat that can handle this without convexing the apex is a must. Softer stones will not allow this. You only need one heavy handed stroke to set the edge back on a soft stone.
