Thread: Using a microscope to define an burr and the edge

at first thank you for the video Very nice one.
what happen at 2.18?
your edge seems like start to broke down?
by your count you have made more then 750 strokes .
Don't You think this is a little too many strokes or you have used only 1 stone honing?
thank you.

Thank you for the information, I know it took some time. Very informative. I've been afraid of the 30K for two reasons: price and simply too fine of an edge.

It would be nice to see the edge after a shave.

Very nice effort you put into this. How did it shave when you were done?

Very cool! Thanks for taking the time to do that and share

Originally Posted by hi_bud_gl

what happen at 2.18?
your edge seems like start to broke down?

It does certainly appear so to me too.

Maybe this happens to all of us, to varying degrees, in the honing process. It seems logical. The more metal taken off on each side, the thinner the bevel becomes at it's most extreme edge. The odd piece is bound to break off.... and not always in a uniform manner. The end result still looks great.

Nice work.

Sham, the "edge breakdown" you mention is apparently the burr being taken off, from what is written in the photo captions.

But I myself can't see the burr forming until that point...

Thank for the question about time line at 2:18.
I think what has really happened are 2 events. One is that because I taped the spine at 1:45 at that stage all of the honing was focused on the edge and a new micro bevel was beginning to take shape. And secondly a few frames after that I began to hone on the back of the blade in alternate sequences.


So in actuality what we are seeing is the creation of a new bevel, its birth and refinement including the polishing and edge delineation.
I should apologize because this was not at all planned out ahead of time or very well, and my sequences just came to me on a whim. Seven or eight hundred strokes is probably 6-7 hundred too many. For example, the first photo #64 established a scratched out bevel well enough, the next 30 strokes up to photo #67 were redundent.


After this point and up until the marker 1:45 it was all about polishing the bevel with clear water and lighter strokes using in total about 700 strokes. If I had known that I was going to introduce a micro bevel later on, I could have skipped all of these earlier strokes on the primary bevel and just done the polishing on the micro bevel and I could have forgone 690 strokes right there.


The two photos jumped out at me, #98 because of the dramatic nature of the burr precariously holding out, & #104 where the edge cleans up by stropping on my palm.


It will try to restructure and compact this whole trial into less than 100 strokes total (a nice short duration similar to a kitchen sink edge refreshment session) shouldn't be a problem to do that, by setting the scratch pattern on the primary bevel, taping to a micro bevel and honing with clear water on both sides right away. I will also copy the same preceedure without tape and see where that gets me in the same number of strokes. Any suggestions would be appreciated. alx

thank you for explanation.

Originally Posted by alx

I did a short honing study using a microscope for practice with the scope. The power is about 150x including the camera. The blade is a Yasuki steel kamisori and the majority of the honing was done on the omote side. Some of the final strokes were on the back of the blade on the ura side.

Originally Posted by MykelDR

It seems logical. The more metal taken off on each side, the thinner the bevel becomes at it's most extreme edge. The odd piece is bound to break off.... and not always in a uniform manner. The end result still looks great.

Thanks for posting that remarkable slide show. After reading the original post and informative comments several times I would explain the "breakdown" or "burring" as follows.

After the bevel is completely formed to an apex the steel at the extreme edge is thin enough to break or flake due to the honing forces. When the groove pattern is coarse, micro-flaking occurs randomly in time and at numerous, scattered locations along the edge. As the groove pattern becomes finer the edge variations are less. So when failure occurs, it is more likely to occur simultaneously to a contiguous swath. Thus, we begin to see fractures forming along continuous lines parallel to the edge. This helps explain why edges become more linear as polish and sharpness increase.

In this case the flaking is probably initiated by the alternating front and back honing as you surmised and by the number of reps which caused fatigue to the thinnest portions of the edge. So I wonder if this observed process is typical of most honing sessions or is it unique to this one experiment because of the large number of reps or the fact that much of initial honing was on one side only?