Thread: How sharp do you like it?

Originally Posted by TonyFranciozi

...Sharpness has be defined as two surfaces meeting at a line of zero width. Such an edge is not possible (with today's technology) but hypothetically, it stands to reason that if those two surfaces are not smooth the edge they create will not have zero width, and thus will not be truly sharp...

Could the edge not have near zero width, yet not be a straight edge? That is, the edge comes together very closely (near zero width) yet it is a ragged edge that comes together with near zero width? Just thinking aloud; not arguing at all

Glen, can you expand on your last post a little? What happens if you 'take the edge too far? Will it become fragile and break?

Originally Posted by carlmaloschneider

Could the edge not have near zero width, yet not be a straight edge? That is, the edge comes together very closely (near zero width) yet it is a ragged edge that comes together with near zero width?

That's a good question, and I really don't know the answer. That's the hardest thing about sharpening for a beginner I think, not being able to see your work. At least not the last micron that matters.

When you are talking about sides of metal being brought together by the use of abrasive particulates, there can be no such thing as "a" line of zero width, it is more about being within an arbitrary small constant of zero width. There will be variations due to the particulates imparting their "scratches" under various rotations of configuration, and random contributions as well. Whenever I talk about sharp I envisage a maximum or upper bound for the whole edge.

As I said above, I do not disagree that higher grit hones will continue the process of bringing the sides closer together. What finishing grit hones will not do in a practical time-frame is take an edge to the point of being able to shave if it is too far away to start with. That's not to say you cannot do it, just that unless a person has enough experience at honing the common historically observed pattern is that they stop too soon and continue up the grits to produce a highly polished and very smooth dull edge.

I find it difficult to believe that the maximum width between two sides, and the makeup of the sides themselves can be considered by anyone to be an artificial distinction. They are physically different things. While I agree that the names we call these two things may indeed be confusing, I fail to see the problem. You can call them "Ted" and "Bob" if you want. It doesn't change the fact that they are what they are.

James.

Originally Posted by carlmaloschneider

Could the edge not have near zero width, yet not be a straight edge? That is, the edge comes together very closely (near zero width) yet it is a ragged edge that comes together with near zero width? Just thinking aloud; not arguing at all

Glen, can you expand on your last post a little? What happens if you 'take the edge too far? Will it become fragile and break?

Why you just figured it out for yourself

There are three aspects to the edge 1. Smoothness of the bevels 2. The sharpness, which is defined as the absolute micron width of the edge (about .38 microns "max" per the Verhoeven papers) 3. the "Eveness" of that edge from heel to toe (what we often refer to as jaggedness)

Each razor has a absolute max sharpen point by geometry and steel combined with the hones and the pressure (the honer)
When that point is pushed past then the edge fails, how it fails is determined by the razor itself and the honing... Most of the time it is a Harsh, Fragile, Chippy, edge, to learn this for yourself, push the edge and see what happens and how it feels...

On a practical level what I am trying to say is this: If you hone an edge at 240 grit, the sides will be rough, and the edge will be quite wide. At 1000 grit the sides will be smoother and the edge will be narrower, but still not nearly as smooth and as narrow as they would be at 4000 or 8000 grit. What I am saying is that sharpness (the width of the edge) and smoothness (of the planes that form the edge) progress linearly, and in tandem.

In the above example I'm assuming the blade is being honed properly. I mean, you could polish a butter knife on crox and it would be very smooth and shiny but still wouldn't be sharp because the edge is round. That is something completely different.

Originally Posted by TonyFranciozi

On a practical level what I am trying to say is this: If you hone an edge at 240 grit, the sides will be rough, and the edge will be quite wide. At 1000 grit the sides will be smoother and the edge will be narrower, but still not nearly as smooth and as narrow as they would be at 4000 or 8000 grit. What I am saying is that sharpness (the width of the edge) and smoothness (of the planes that form the edge) progress linearly, and in tandem.

.

There is the flaw in your hypothesis, on a practical level, using your words, the edge gets sharp at a much lower level and much faster then it gets smooth...
Sharp is easy, search out the thread where the guys did a 1k bevel shaving test, sharp is there really early

Originally Posted by tiddle

Personally I look at anything above 8k as a finisher regardless. I love my Nani 12k, but I would like to try mike's zulu at some point, and the nubutama bamboo 15k. I figure as long as the grit or the nati stone isn't more than double the 8k grit there's no need to stack the 12k and 15k or 12k, 15k or 16k and 30k. I say 8k, 12k stop. 8k, 16k, 30k stop. or 8k, natural stop. Just me though.

Kinda of confused. Why 8k,12k stop or 8k, 16k, 30k stop i mean going from 8-30 is 3x the 8-12 isn't it? But I have heard the nani 12k is pretty much the same as a shapton 16 because of what it's made of... not 100% but I thought I read that somewhere.

By the way I had a wonderful shave today...my 1st wtg pass felt like nothing and it made it look 80%bbs.... was tempted to not even bother with the rest of the passes lol. STILL HHT'D AFTER SHAVE TOO!!! was happy bout this

Noobs for ya

Originally Posted by gssixgun

Sharp is easy, search out the thread where the guys did a 1k bevel shaving test, sharp is there really early

1k might give you a shave but that doesn't mean the cutting edge is as thin as it is after 8k. How could it be?

Originally Posted by TonyFranciozi

1k might give you a shave but that doesn't mean the cutting edge is as thin as it is after 8k. How could it be?

You are jumping to a conclusion,,, Try it and see what you find


If I were better at those cool computer graphics things I could make it more clear but alas I am not, Try and visualize that edge in 3d

Originally Posted by gssixgun

Try and visualize that edge in 3d

Hmmm . . . still not convinced hahaha.

It's times like this I wish I had an electron microscope.