Is shaving sharp sharp enough?

[miro44]

You really need to decide that question for yourself, if you don' t need it any shaper, than keep it shaving sharp.

 

[DainBramage]

I managed to keep it shaving sharp using a Sharpmaker about once a week, and didnt go back to the sander for about 4 months. The trick is to sharpen at an angle about 5 degrees less per side than the touch up angle. This reduces steel removal to a minimum, and the narrow, higher angle bevel doesnt reduce cutting enough for me to notice.

So is your primary bevel closer to 10 or 15 degrees per side?

 

[Ben Dover]

It's all personal preference. I prefer an edge that is at least as sharp as a straight razor, and is mirror polished.

You might ask. "Why do I want to get it that sharp?" Well....... Because I can!


Ben

 

[nozh2002]

Once a knife gets to the point of shaving sharp, can clean the hair off of your forearms for example, is there a need to try to sharpen further?

First of all this is a question of your sharpening skills. I can make knife sharp to slice hair. And so when I sharpen knives I always continue to sharpen to this level - do not see reason why should I stop before I rich my best.

Do I need it to slice hair? - Yes I do. As an example this sharpness became handy to me to take away splinters. Knife this sharp can cut skin on my finger without any pressure at all - I just make small accurate cut on top of splinter without drawing blood. Knife which are not sharp enough will require some pressure and in result push splinter deeper and make cut without control - injure instead of fix the problem, so I will end up with splinter deeper in my flesh and bad cut on top of it! This is just an example and do not cut out splinter yourself this way.

There are many other use you will find when you got you knife to be really sharp. Please do not fall to this silly excuse not to sharpen you sharpening skills - "No need to get knife sharper". Learning is always good!

Also shaving sharp is indication of edge not being round not really indicate all aspects of sharpness. You can have coarse or fine edge being shaving sharp - it is not a criteria of sharp edge but more like good edge.

Thanks, Vassili.

 

[smitty0331]

Shaving sharp is only sharp enough when you can shave the hair off of a sleeping mouses butt without waking him up.

 

[me2]

So is your primary bevel closer to 10 or 15 degrees per side?

The primary is much shallower than 10 degrees, but I didnt do that. The angle off the sander is roughly 15 degrees, and I touch up on the 20 degree rods for my Kershaw Vapor. Its was my work knife until my Byrd Cara Cara. I keep some kitchen knives at 12 and touch up on the 15 degree slots on the Sharpmaker.

 

[Lurker]

For me personally, there are times when less than shaving sharp is good enough. For beaters and especially knives that I am not the primary user of, I can put a "working edge" on one in well under a minute and I often stop there and call it good enough. These might just barely shave a little bit, but not well. Why bother to invest my time putting a really nice edge on a knife that will be immediately used to cut on glass or ceramic and then tossed into a sink? I call it quick and dirty sharpening and there is definitely a place for it.

However, if you are doing my vasectomy, then go for hair whittling sharp. It all depends on the use. For my EDC, I stop at shaving-sharp and have never bothered much with ultra-fine stones or stropping. I just don't see the need and I consider sharpening a chore to be completed rather than a hobby to be savored.

I would be willing to bet that even for the sharpening fanatics, if they own a working axe, a splitting wedge, utility scissors or a lawnmower blade, these things are not hair whittling sharp or even shaving sharp even though they would work better if they were. Everyone draws the line somewhere.

 

[bbcmat]

My goal is the equivalent of shaving sharp (I find once the blade press cuts newspaper it will cut hair easily) AFTER the blade has done some work.

For a general purpose blade that is a few full slices (not press cuts) into clean cardboard, and for kitchen knives it is a few slices into a clean plastic cutting board, then 15-20 slices into clean used photocopy paper that’s been folded 3x.

If the burr / weakened edge has been fully removed – there will be negligible difference across the length of the cutting blade and the overall sharpness will stay high. The “glide” through the material is consistent and without draggy (burred or dull) areas.

I give a few alternating passes on the finish stone (after the test) and the blade is ready for use.


I started into this routine to weed out the combinations of good steel, low angles, and light usage patterns that would not hold an extremely sharp edge. Cardboard cutting really shows off how well a blade is deburred and the quality of the steel AT THE EDGE. I’d always use cardboard if I didn’t have to be concerned about scuffing on the sides of some of the blades I sharpen.

MAT

 

[Vivi]

I don't think so, unless you want to get it to "clean the hair off your face", in which case you risk getting an edge that will chip very easily.

Best,

Edalb

Could you elaborate? I've never noted an inclination for very, very sharp edges to chip more than somewhat sharp edges.

I think it depends on what you are planning on slicing. You going to be sawing vines off the roller of the chipper, or are you going to slice up milk bottles or cardboard? Maybe just open an envelope? As someone alluded, really ultra-sharp blades can be fragile as a consequence of being too thin for the job at hand. Don't believe it? Slice/whittle a few bottle corks with a straight razor. Look at the nicks in the blade. Now try it with your hunting knife. What's the difference?

Edge geometry. Give your hunting knife the edge geometry of a straight razor and see how tough it is then. Sharpness does not reduce toughness, thin geometry does.

For me personally, there are times when less than shaving sharp is good enough. For beaters and especially knives that I am not the primary user of, I can put a "working edge" on one in well under a minute and I often stop there and call it good enough. These might just barely shave a little bit, but not well. Why bother to invest my time putting a really nice edge on a knife that will be immediately used to cut on glass or ceramic and then tossed into a sink? I call it quick and dirty sharpening and there is definitely a place for it.

While I tend to agree with your beater point (Knives that I know are going to see abusive cutting just get shaving sharp, no more), why would you cut on glass or ceramic?

I would be willing to bet that even for the sharpening fanatics, if they own a working axe, a splitting wedge, utility scissors or a lawnmower blade, these things are not hair whittling sharp or even shaving sharp even though they would work better if they were. Everyone draws the line somewhere.

Would you like a video of me shaving with my Fiskars two handed axe?

Every cutting edge that I use on a regular basis is capable of touching up missed spots from a morning shave. Why shouldn't they? What possible benefit is there to having a duller edge? Why are we even having this conversation in a knife forum of all places?

 

[3wolves]

Could you elaborate? I've never noted an inclination for very, very sharp edges to chip more than somewhat sharp edges.

The thinner the edge the easier it is for it to chip or roll. Take a hatchet and a straight razor for instance, If you take a few swings at concrete with each, the straight razor will be totally destroyed but the hatchet will have just a little chipping or rolling.

Edit: I don't know about your fiskars though.

 

[Vivi]

The thinner the edge the easier it is for it to chip or roll. Take a hatchet and a straight razor for instance, If you take a few swings at concrete with each, the straight razor will be totally destroyed but the hatchet will have just a little chipping or rolling.

Edit: I don't know about your fiskars though.

Compare the geometry of each and you'll see why. Are you sure you're not confusing geometry and sharpness? My shaving sharp fiskars can cut down a tree without getting chips, and will still take hair off my arm. Edge geometry and sharpness are, for the most part, different aspects of a cutting edge. They have very little influence on each other. Cutting ability is measured by both, but durability is more relative to geometry than it is sharpness.

The straight razor doesn't fail the concrete block test because it's sharp, but because it has very thin edge geometry designed for a different purpose than chopping concrete.

 

[Broos]

It all depends on what you define "shaving sharp" and "sharp" as. If you define "sharp" as cutting ability, and associate "shaving sharp" as polished edges only, then the question is about two different qualities. Some will also associate "shaving sharp" as a thin edge, further muddying the water.

I do not think I would try to shave with any 320 grit edge, even if it did slice like the dickens, because those big microteeth are going to be ripping through the skin on my chin. But I would give it a shot with a chisel edge at a 45 degree angle, if it was sharp enough.

 

[Vivi]

It all depends on what you define "shaving sharp" and "sharp" as. If you define "sharp" as cutting ability, and associate "shaving sharp" as polished edges only, then the question is about two different qualities. Some will also associate "shaving sharp" as a thin edge, further muddying the water.

I do not think I would try to shave with any 320 grit edge, even if it did slice like the dickens, because those big microteeth are going to be ripping through the skin on my chin. But I would give it a shot with a chisel edge at a 45 degree angle, if it was sharp enough.

As far as I'm concerned, associating edge geometry with sharpness is fallacy.

For instance, if you have a knife with a 40 degree inclusive edge and another with a 20 inclusive edge, then apply a 50 degree inclusive microbevel to each knife, the actual cutting edge will be the same thickness, but one knife will seriously outcut the other. This is what I mean by cutting ability. It is a combination of edge geometry and sharpness. Durability is, from what I've seen, determined almost solely by geometry, sharpness has very little effect on it.

I think the terms need to be properly used and defined. Sharpness and cutting ability, as I've explained, are different things. Cutting ability is affected by more than just sharpness, so it's wrong to say that two knives which are equally sharp at the very edge have different levels of sharpness because of their edge thickness variations. One has more cutting ability than the other, not more sharpness. Hope my explanation makes sense.

This is the basis for my response to the axe VS straight razor chopping remark. Sharpness has no effect here, as both cutting devices can be sharpened to the point of shaving a man's face. The difference is the geometry, which directly influences the toughness of the knife. Blade steel will also be an important variable to consider, but that's outside the current discussion.

This might be one reason why some people advocate "less sharp" for hard use cutting tools, which is illogical to me. They might be defining sharpness in their mind as the level of honing on the edge + the edge geometry. When I advocate shaving sharp edges on felling axes, I am not saying that I would also put on a 10 degree inclusive edge on said axe. I'm merely saying that not having the very edge of the axe as sharp as possible is utterly counter productive, same with "working edges" on pocket knives.*

*Barring situations we've discussed where the user knows the knife will see abusive work and sharpening the edge to an 8000 grit polish that whittles hair would be pointless. The knife I keep in my trunk is never sharpened to the degree that my EDC is, because that knifes role is to cut grip tape. On that knife, "working edge" is practical. On an EDC that slices food, cardboard, opens mail, trims fingernails etc, "working edge" is, to me, an excuse for laziness or poor sharpening ability.

 

[Greg]

What Vivi said.
Greg

 

[Jeff Clark]

Some of the question relates to how much of the blade you consider as being "the edge". You could define it as the distribution of the top atoms stacked on the apex of the edge, but that doesn't seem remotely useful. You can visualize the edge as being the top of a slightly rounded or flattened ideal wedge contour and hence express it as a radius of curvature or a width of this apex, but this only seems applicable for extremely thin (thinner than hair) or extremely soft material. For practical applications the "edge" includes both the width of the apex of the edge and the effective angle of the edge back some (application dependent) distance behind the apex. If you are interested in shaving performance your "edge" probably includes the blade from the apex back a few hair diameters of bevel. If you use a knife on thicker material with some significant stiffness your practical "edge" is likely to include the apex of the edge and the bevel geometry back at least a sixteenth of an inch.

When I sharpen a knife I am usually controlling the contour of the knife from the apex of the edge back a quarter inch from the apex. If the knife is not under 10 degrees per side when you include that region I will regrind the blade until I get that contour. I will smooth or polish that region with a slight convexity. I will try and reduce the apex of the edge to well under a micron of thickness, but that surface is not an "edge" unless what comes behind it is an adequately acute wedge. For me the edge includes the contour of that wedge back around 1/4-inch.

 

[Kaizen1]

I think in most cases for EDC usage, getting past shaving sharp is more than likely not necessary. Sure is fun though.

 

[stabman]

Once a knife gets to the point of shaving sharp, can clean the hair off of your forearms for example, is there a need to try to sharpen further?

If you circumsize gnats for a living, then sharper is good.
For me, once I can do emergency face shaving if I miss a patch with the electric, it's sharp enough.

 

[nozh2002]

As I sad in many cases it is more about abilities... If you can sharpen above shaving sharp and this is not an act of heroism for you - you will be sharpening all blades to that point. At least this is what I am doing and do not really see why should I stop in the middle of sharpening to keep it semi-dull from my point of view.

To go beyond shaving sharp - whittling hair sharp you need piece of leather on wood (few bucks), Green Rouge around $7 and less then 5 minutes. Why not to make it? Really, why?

However if you need to learn this simple skills and you just lazy to learn new stuff - this may be an excuse. However I like to learn myself...

Thanks, Vassili.

P.S. I forgot to mention most beneficial property of whittling hair edge - it last longer! As I sad in different thread I was able to shave my face (not entire, but on soft sensitive skin under mouth) before and after cutting 77 ' of thick watercolor paper on the wooden base.

 

[Vivi]

To go beyond shaving sharp - whittling hair sharp you need piece of leather on wood (few bucks), Green Rouge around $7 and less then 5 minutes. Why not to make it? Really, why?

This is the mentality I don't understand. I came here in 2005 I believe and did not know the first thing about sharpening knives, and now I can make hair whittling edges. I am not particularly dexterous or gifted, I just read, learn, experimented by trial and error and got the results I wanted.

If someone proposes a sharpening method I've never heard of, first thing that comes to mind is to go try it and see how it works for me. Your angled bases for your sharpening stones for example, I like that idea. I plan to build myself some in the future because it seems like a more precise way of applying microbevels.

You're very much correct in that once you can sharpen like this, it's nothing special to you. It's just the way you sharpen. I spend at most 3 or 4 minutes a day sharpening my EDC to get it above shaving sharp all the time. It's a small investment for a big return IMO.

 

[theonew]

I'm just gonna throw this in for whatever its worth. I use nothing but my eye and hand to set the bevel when sharpening. I don't use a strop anymore and can get an edge to hair whittling sharpness just using an ultra-fine (3 micron) ceramic rod and an edge leading stroke (the opposite of what is commonly used on a strop). I try to put a 1 - 2 degree micro-bevel on the edge when I use the UF ceramic. This isn't easy and takes a very fine touch. If the angle is too acute you just end up polishing the bevel and if your angle is too obtuse and/or your stroke to rough you end up just flopping the burr back and forth until you need to re-sharpen the bevel and start over. But when you do it right you can take a 9 micron shaving sharp edge to hair whittling sharp in 10 to 20 strokes (more sometimes depending on the steel and blade thickness). Do I do it right every time? Hardly. But the more I practice the less I fail and the more I learn to both sense the proper angle to use and interpret the feedback from the feeling of the edge itself as it slides across the rod. To me free hand sharpening is a skill that can always be improved upon and I enjoy doing it.