Microbevels

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sodak

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I decided to start a new thread on microbevels since we were inevitably hijacking another on burrs and steels.

First of all, what is a microbevel? Why use them? Are there both pros and cons?

For the sake of this discussion, let's agree that the primary grind is the major grind shape of the blade. For a full flat ground blade, it's obviously a flat grind. For a mora, it's a saber grind. For some others, a full convex grind from the spine to the edge. Some have a full hollow or high-hollow grind. Some others are combinations - I've seen some saber grinds that are hollow from mid-blade to edge.

The secondary grind would then be the edge bevel. It is ground by the maker to form the edge. Some knives, such as chisel edge knives (or chisels) or moras, don't have an edge bevel. The primary grind extends all the way down into the edge.

Consider the case where a knife has a very thin edge (secondary) bevel. It may or may not have a thin primary bevel, we'll get into that later. With a thin edge bevel, it is possible to damage the steel from either cutting the wrong things, too much sideways force, etc. Enter the microbevel. Once the secondary bevel has been set, a third (very small) edge bevel, somewhat more obtuse than the secondary bevel can be quickly sharpened into the edge by slightly increasing the sharpening angle. This microbevel can have several advantages:

1. It is very quick and easy to set on a sharpening stone, especially with a thin secondary bevel.
2. It is very quick and easy to re-sharpen.
3. It thickens the edge slightly, providing for more edge stability under hard cutting.
4. While it theoretically makes cutting a little more difficult, in practice, it doesn't appear to be a big enough difference to be noticed.

Here's an example. Sorry for dredging it up again for those who have seen it already. I have a Queen 4180 in D2. Great knife. But the edge was a little too thick for my liking. So I spend some time on a DMT blue and thinned it out. In doing so, the edge bevel is now 1/4 - 3/8's of an inch wide. It can take a while to sharpen, because now there is so much surface area of metal to remove. For a long time, I really liked the results - this thing can really cut cardboard, carpet, etc. Good stuff!

Then one day I decided to cut up some pine fuzz sticks, using a very slight scooping motion. Here is the result:

p1010048.jpg


Obviously, my edge is to thin for this kind of work. Check out those chips! What to do?

Well, I pulled out the DMT blue, and instead of spending an hour on the bevel, I increased the angle slightly, and put in a microbevel. It took less than 5 minutes to remove all but one of those chips, and it's not noticeable unless you really look.

p1010007-4.jpg


The knife still cuts as good as ever, but no more chipping. Yes, I went back to
the same wood and tried it again, no problem. The microbevel put enough steel
behind the edge to give it the stability that it needs. And it still cuts like a demon, and still cuts much better than the original stock edge did.

I don't put microbevels on everything, my straight razors just have an edge bevel. And if you have a fairly thick edge on a larger knife that works for you, then a microbevel might not make sense. But if you have a thinner grind that needs a little support without sacrificing cutting ability, give it a try!
 
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I think that a micro bevel works well on a EDC. It's not for a specific purpose but is called upon to perform many functions. I have been using a 20 degree micro bevel with a 15 degree back bevel for the EDC's I have sharpened for friends and customers. They all seem pleased with the results.
 
Micro bevels work for most of my knives. I find they demand thin and acute edge bevels for best effectiveness.

Ideally, I think most knives should have a zero edge. This allows for the keenest edge on a particular blade. However, such things are often very difficult to maintain. This is where the micro bevel comes into good use. Rather than having to grind away at the full primary grind, only a few swipes at the very edge, at a slightly less acute angle, will renew the cutting ability. And since it's a micro bevel, the advantage of a thin edge is maintained.
 
The reason I am such a convex nut is the same as reasons for a micro edge bevel. With the convex you get all three in one, primary secondary, and micro. I personally like thin edges, heck the truth is I like too thinn of edges the most. Convex grinds/edges the way I use them I can keep a thinner secondary edge profile with a edge that isn't as week as if I had a flat ground secondary edge. I also think but have no proof the smooth curve of the convex bevels helps cutting glide through what ever your cutting. For me the convex is quick and easy to maintain and or sharpen to a new edge, and that is mainly why they are my edge type of choice.
 
db said:
The reason I am such a convex nut is the same as reasons for a micro edge bevel. With the convex you get all three in one, primary secondary, and micro. I personally like thin edges, heck the truth is I like too thinn of edges the most. Convex grinds/edges the way I use them I can keep a thinner secondary edge profile with a edge that isn't as week as if I had a flat ground secondary edge. I also think but have no proof the smooth curve of the convex bevels helps cutting glide through what ever your cutting. For me the convex is quick and easy to maintain and or sharpen to a new edge, and that is mainly why they are my edge type of choice.
Click to expand...

My thoughts exactly.


Like the pic's I posted in the other thread showing the difference between a edge sharpened by a guide and one done by hand. The edge sharpened by hand lasts much longer.
 
Outstanding post, sodak! You make everything absolutely clear, and your example with the D2 blade illustrates things wonderfully. IMO this really should be made a 'sticky'; invaluable information, especially for newer blade enthusiasts with sharpening questions.

For reference, here's the early thread mentioned both by sodak and knifenut1013, which is a very worthwhile read in itself:

https://www.bladeforums.com/forums/showthread.php?t=631113
 
Great post, Sodak. It clearly illustrates all I like about the microbevel, even if it has been called a "cheater" bevel. I've always just called it my lazy man's bevel. It just plain saves tons of time and work while greatly strengthening your bevel, so there isn't much of a reason not to use it.

Mike
 
I really do not want to wear down my blades. I also do not like cleaning my stones constantly, so micro is the way to go.
 
As a tangent to this thread, and I hope Sodak doesn't mind, but how do most people apply their microbevel? Strop? stone? Crock sticks? etc.

I prefer to use a ceramic rod (Spyderco Profile Hones or Idahone, White Fine grit) held at about a 45 deg. and just use the weight of the knife (read that no pressure) for 3-4 swipes on both sides.

Good job Sodak, nice read!

Be safe.

NJ
 
I'll make this a sticky for you guys for the time being (subject to final approval by the forum's moderator whose authority I have no wish to usurp.)
 
Shucks, DOW, you're gonna make me blush. Thanks for the kind words. Aside from "Traditional" this is my favorite forum as I learn a lot from you guys in pursuit of the keen edge.

Carry on gents.
 
Lately I've been putting on a microbevel of 20-22 degrees or so after going to the 220/1000 King combo stone at 17. I dont really have any noticable effects on edge holding, so at this point its purely a way to save wear on my 0.3 micron lapping film. There is a barely visible, mirror polished line along the edge and it works on my favorite kitchen knives like a charm. Touch ups can be done on the Sharpmaker, but I generally resharpen the whole edge. The kitchen knives usually take at least one trip through the dish washer without me knowing until I try to cut with one and notice the dents in the edge.
 
Confucious say, for tough cutting, a very thin edge with the right microbevel will survive and prosper much longer than a low angle zero edge paper push cutting monster edge. The challenge is to try to get the microbeveled edge to push cut paper almost as easily as the zero edge!
 
since I freehand, the edge is naturally convexed a little, and when I strop, raise the angle & only the very edge is polished. maybe that's micro-stropping? :)
 
Native Justice said:
As a tangent to this thread, and I hope Sodak doesn't mind, but how do most people apply their microbevel? Strop? stone? Crock sticks? etc.

I prefer to use a ceramic rod (Spyderco Profile Hones or Idahone, White Fine grit) held at about a 45 deg. and just use the weight of the knife (read that no pressure) for 3-4 swipes on both sides.

Good job Sodak, nice read!

Be safe.

NJ
Click to expand...
Not at all, I like it when threads take twists and turns. I generally get the best results with Spyderco UF Hones, followed by a stropping on linen with Thier-Issard diamond paste.


me2 said:
Lately I've been putting on a microbevel of 20-22 degrees or so after going to the 220/1000 King combo stone at 17. I dont really have any noticable effects on edge holding, so at this point its purely a way to save wear on my 0.3 micron lapping film. There is a barely visible, mirror polished line along the edge and it works on my favorite kitchen knives like a charm. Touch ups can be done on the Sharpmaker, but I generally resharpen the whole edge. The kitchen knives usually take at least one trip through the dish washer without me knowing until I try to cut with one and notice the dents in the edge.
Click to expand...
Our wives must be related... ;)

I often wonder about the relationship between microbevels and convex grinds. Some people, I'm thinking Joe Talmadge, but could be wrong, actually argued for more than one microbevel.

One thing that convex grinds have going for them, I think, is the reduced friction due to the varying (lessening) angle. When cutting something that might "stick" to a zero grind, the convex, due to the angle being reduced into the primary grind, has a tendency to have an air gap. Sushi blades have that tendency by design as well, being a chisel/hollow grind. I wonder if the microbevel has that effect that helps cutting, but still not sure if it's too small for having that effect.
 
Hi sodak

Good post. Thank you.

What you think is best angle for bevel and micro bevel for diferent hardnes steels?

Thanks
Frank
 
Hi Frank,

I was hoping this thread would stimulate this exact discussion. In the other referenced thread, some have been very happy with a 40 deg microbevel. I'm still experimenting, although the harder steels can take a thinner edge grind due to their higher strength. The queen pictured above had around a 20 - 25 deg primary, IIRC, after I thinned it out. The microbevel is probably 30 - 35.

Another thing to consider is the width of the edge grind at the shoulder. Really thin widths don't need much, if any help. Dozier, Krein, and Wilson all come to mind here. The primary grind is thin enough that the edge grind is almost like a microbevel, if that makes sense. I have a Wilson fixed blade in CPM 10V at 64.5 HRC. The edge bevel width is so thin, that completely re-setting the edge on a DMT benchstone takes a minute or less. That's completely re-honing the edge using a sharpie for checking. With that kind of performance, obviously, a microbevel is a moot point. Now my CS Trailmaster, that's another ball game altogether.
 
Hi Sodak,

Thank you very much. Not sure but I think good micro bevel has to be big. More than 35 degrs. Maybe 50 like on some microtom baldes.

Thanks
Frank
 
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