This may be on of those depends type discussions, but I think I will ask it anyway. I can make the apex of my knife blade as sharp as I could ever desire it to be, I mean my knives are really sharp. That part is actually easy and WEPS excels at making amateur knife sharpener get expert results. But it seems to me that there are two camps when it comes to knife sharpening. The first is the utility blade, toothy cutting edge for a given purpose, food prep, box, rope, binder cutting etc. This is not the issue I want to address. The second group is concerned with the cosmetic aspect to knife sharpening. Obtaining a mirror finish. These are the big spenders, the micro and nano obsessed crowd that can not seem to get enough technical information on knife sharpening.
These are the ones that will eventually make Clay a multi millionaire because they buy every grit and gadget in pursuit of that perfect mirror finish. I include myself in that group :ohmy:
So, here is what I would like to discuss here if anyone else is inclined to. I have had trouble getting a “perfect mirror finish” and I am not sure exactly what I am doing wrong. By perfect, I mean glassy clear no scratches visible when observed with out magnification or maybe a 10x loupe. I am not talking 200x or 2000x here.
I have seen the result I am after in photos here and at other forums and on Youtube, but the process by which folks get there is a bit vague. I don’t think it is (in my case at least) not having the right tools. I have every stone and grit from 50 to .5uM. That should do it. I suspect my problem is that I am either not using the right technique such as direction I drag the stones over the steel of the blade or I am not doing enough strokes from stone to stone and trying to get more out of the finer stones than they were designed for or perhaps it is because I am using them in the wrong order.
The first possible problem, direction of travel for the stones over the metal…
Do I do a circular scrubbing motion or an up and down sawing motion or push up, disengage the stone, reposition the stone below the knife and push up again and repeat until the stone has made it as fine a scratch pattern as is possible? I have tried different methods and the circular seems to get the best results at the medium grit level but not when it gets to polishing and shining. There it seems that the up and down sawing motion works better with the micro fine ceramic, and then the strops which are obviously one directional to prevent scarring the leather. I don’t know, if you have a suggestion, I would love to hear it.
Next is the question of how many strokes and when do you advance to the next level of finer grit or abrasion?
This is probably the depends part. I know that different steel hardness, and thickness of the metal and other characteristics of the blade come into play, but I am wondering if there is some kind of rule of thumb. How do you know when you are done with a certain stone. To much and you are needlessly wearing away metal on the blade and may wind up making one side more beveled than the other. Not enough and the next finer grit stone or whatever is being asked to do too much or at least more than it was designed to do. I’ll exaggerate to make a point here. You would not try to re-profile a blade with a 1000 grit stone. It could be done but it would take forever and is better done with a progression of stones. I think you all get the point.
And my last proposed issue, is grit order and where do you need to stop?
I suppose there are a couple of aspects to this. First if you start at 50 grits to say re-profile an edge, you are starting with some pretty deep and severe scratches. If you keep grinding away with the 50 then the 80 then the 100 etc. it seems like you are just eating away metal and perhaps even moving the apex from side to side making the bevel uneven. Not sure about that part, but logically it makes sense. So it seems like you should stop just when you get a burr on both sides and immediately go on to the next grit. That makes sense a the lower grits, but as you progress, it becomes less about the edge and more about the polish on the shoulder of the edge. So, how long do you continue this grinding away metal with a given stone?
Should the answer be, you just have to experiment and learn by failure or success? Or is there some sort of clue as to what to look for in the scratch pattern or shiny-ness of the bevel. I don’t know. I just kind of scratch away until I feel like I have gotten the whole side about even and there is a burr. Problem is when I get to the final grits for burnishing, there are always still some obvious scratches visible without magnification on an otherwise shiny mirror finish.
Also, with regard to grits and abrasives. The grit on two of the diamond pastes for leather strops (5 uM and 3.5um) is between the coarse and the fine sides of the super fine ceramic. But because they are on leather, do they actually polish more than the ceramic stone which is more fine on the fine side (1600) than the paste. Also, at what level do you have to go to actually get a flawless shiny blade edge without magnification? Is .5uM enough, do you need to use the sprays at .012 or can you go from the fine paste at .05 to the bare kangaroo strop to get that result? Kind of like the amazing shrinking man movie in the fifties for those of you old enough to remember that. He kept shrinking until he became microscopic and then he realized that he was entering a whole new universe where the process started over again to sub atomic particle size. It’s the everything is relative theory.
I know at some point you are polishing to high magnification levels of shine not visible to the naked eye, but how far is it practical to go on these stropping sprays and abrasives to get a real world mirror finish?
If you have stuck it out to read down this far, I apparently have tapped into a dilemma that you may have. I suspect that this issue is central to a number of people from reading the various threads here. There is a constant theme of getting a mirror finish and so many threads and posts are asking questions related to this in one way or another. I hope that in some way, this will help one or more of you, as i hope to learn here from others experience and knowledge.
So thanks.
