Bevel scratches among other things

Liquid Cobra

Liquid Cobra

Joined
Feb 17, 2013
Messages
737
Please help.

1. I can get a mirror polish on my edges, but there are usually some scratches that don't/won't go away. They are hard to see in photographs which makes me wonder if other people have the same problem but just don't talk about it. Do you have these scratches as well? Or is it just me.

2. I read all the time how people are reprofiling their knives, and they do it in about 30 minutes. How is this possible? Again, are people exaggerating? Are they misinterpreting what reprofiling actually means? It takes me a couple hours at minimum to completely resharpen a blade including reprofiling.

3. Why is my bevel wider on one side of the blade compared to the other? How is this possible if I'm using the same angle on each side?

4. Using the edge pro do you change he amount of pressure you are applying while sharpening? Could this be why it takes me so long to reprofile? I don't put use much pressure if any on my 120 stone and up. Should I be pushing harder?

Super frustrated. Thanks.
 
Don't be super frustrated! They are just edges! There are simple answers to all of your questions.

1. - First off, it is completely unnecessary to mirror polish your edge. It might LOOK cool to you, but it does nothing at all functionality-wise. I would not worry about this in the slightest bit. Just sharpen and use. It's an edge, not a fender on a Ferrari. Anyway, if you must have a mirror polished edge, you must work through progressively finer grades of abrasive until you get to a VERY fine grit. The scratches you see on your mirror finish is either because you didn't spend enough time on one stage or another, or because you didn't clean your edge completely in between stages. Example - you go from a coarse grit to a finer one without completely cleaning the abrasive off your edge - the edge will look shinier, but will have scratches. Why? Because the finer compound polishes the edge, but the coarser compound rubs around on the edge scratching it as you are polishing it with the finer compound. Get it? There is no secret trick. You just move through progressively finer abrasives CLEANING THE EDGE COMPLETELY between stages until you get a mirror finish.

2. - Time of reprofiling an edge varies. It depends on the angle of the starting bevel, and the angle you want to end up with. I personally would never spend more than a few minutes. I would just use diamond abrasives and get it how I want it quick. If you are just grinding away for 30 minutes plus, you are removing a lot of metal. You will eventually wind up with a little toothpick blade. Have you ever seen a very old, well used, well loved knife owned by a very old man? Toothpick blades. That's what I'm talking about, and it should take years and years to get to that stage. If you are "reprofiling" for hours on end, you will get your knife there quick.

3. - That's because either your angle really IS different, or because the edge is ground at a different angle relative to the actual blade grind to begin with. Just because your sharpening system (no matter which one you use) says 30 degrees, doesn't mean it is actually absolutely positively 30 degrees on both sides. Trust me, I've owned just about all of them and none of them are dead on perfect. They all have variables to them that affect edge angle consistencies. (how you hold the knife, mechanical inconsistencies, etc.) My solution to this problem is: it isn't really a problem to me. Do your knives cut things? Are they as sharp as YOU like them to be? If they work ok, the rest is just aesthetics.

4. - The harder you push, the more metal it grinds. Want to grind more metal? Push harder and go faster. Want to grind less? Don't push as hard go slower. If you want to truly reprofile an edge, try using diamond abrasives. They work fast. Do you know how to sharpen freehand? You might want to try that and try to hold a very consistent angle. I wouldn't let any of this stuff stress you out too bad. It's just an edge, and as long as it cuts the way you want it to, there is no problem. Regardless of what you see on here, or what anybody else says.
 
I wanted to add one thing. If you do achieve a mirror polished edge, be very careful not to touch it to anything. Almost everything will scratch it!

Case in point: I polished the flats of a flat ground blade down to 1200 or 1600 grit. (can't remember which) It was a true mirror finish. I cut a few things with it - scratches! I wiped it off with a napkin and it scratched the hell out of it! A napkin! It looked like I wiped the blade with sandpaper.
 
You've given me se great advice. I took another shot at it tonight. Although it isn't perfect, it's sharp. That's what I'll be focusing on moving forward.

Thanks again for taking the time.
 
No problem at all man! I'm sincerely glad I could help.

Dude, nothing in this big wide world is ever perfect. Absolutely nothing is truly perfect! All that matters is if it does what you want it to do, and it looks good to you.

I really wouldn't worry about a mirror polished edge, unless it is maybe on a presentation knife that will never cut anything. If your knives work for a living, just sharpen and use. No stress!
 
rutcrazed said:
Pretty has never helped cut anything. Sharp first, pretty last if at all. P.S that knife looks just fine to me.
Click to expand...

Absolutely.

Spyderco Dude - there is nothing wrong with that edge at all. It looks great to me! Plus it looks nice and thin. I bet it cuts like a demon! Good job man!
 
A few years ago, I pretty much exclusively used Spyderco ceramics (including the ultrafine rods) and the best I could do was this:

Sage2.jpg


BossStreet.jpg


Osbourne940.jpg


While these appear to be like a mirror, they aren't true mirrors in every direction, and scratches can be seen with the naked eye. I've had better success nowadays using waterstones and strop compound (up to 0.5 micron diamond spray).



In this you would have to look very very closely, or use a magnifying glass to see the scratches. The key is to really spend enough time on each level of your progression to get the ENTIRE bevel evened out.

In regards to your uneven bevels, I've found that sometimes blades are not ground perfectly centered. This means that the primary grind "leans" towards one side or the other. If you sharpen at the same angles on both sides, this affects the appearance of the bevels on your knife. You may also be unknowingly doing this yourself, as many people sharpen until they create a burr, then flip to the other side--it's very easy to sharpen an unequal amount on both sides when doing this.

I'm not always convinced that people are as honest with their time reporting as they could be. The quickest I've ever taken a knife to something approximating a mirror edge was with a friend's Buck 110 (with soft, easy to grind steel) that I took from years of neglect to a 40 degree inclusive angle was in about 30-40 minutes. Taking a knife with more wear resistant steel (e.g. S30V, S90V, etc.) to a much lower angle like 20 degrees inclusive would probably take me upwards of two to three hours. So I think it definitely is dependent on quite a few variables: how "thick" the edge was to begin with, how low of an angle they are going to, and how far they are refining the bevels. Here's my Umnumzaan that took me about four hours (Edge Pro with an Atoma 140 up through 6 micron diamond films, then to 6/3/1/0.5 DMT pastes) to do:

2013-02-03_18-05-05_74_zps090dbe35.jpg
 
Last edited:
Cynic2701 - great job!

That's what I was trying to get across. For a true mirror finish - you have to make sure you have smoothed out all the scratches you made with the last step with the next step, and clean in between. When you go from something coarse to something medium (whether it is ceramics, waterstones, abrasive loaded strops, etc.) you have to make sure you got all of the coarse scratches out of the edge before you move to something finer. (or you will see the scratches that are left behind)

You also know what I was talking about with the edge bevel almost always being ground at an "off angle" relative to the actual blade grind bevels. I'd venture to say that most people assume their edges are ground at perfect angles from the factory - nope! They are most often canted one direction or the other. That gives you the skinny on one side, thick on the other edge appearance.
 
My mirror polishes have no visible scratches on it. But I spend nearly every day polishing (about 1 minute per knife) with 6000 and 8000. So eventually the scratches get smaller or disappear.
This is why I almost never reprofile. Daily polish keeps my coarse stones dusty.
I rarely re profile and when I do it takes less than 1 hour with my set of water stones (200 400 1000 6000 8000 and natural).

Spend more time on smaller bevel (assuming angles are correct). Many of my Japanese kitchen knives have large bevel on right side 70/30. As long as bevel angle is even there is no difference in bevel size performance.
 
Spyderco Dude said:
Please help.

1. I can get a mirror polish on my edges, but there are usually some scratches that don't/won't go away. They are hard to see in photographs which makes me wonder if other people have the same problem but just don't talk about it. Do you have these scratches as well? Or is it just me.

2. I read all the time how people are reprofiling their knives, and they do it in about 30 minutes. How is this possible? Again, are people exaggerating? Are they misinterpreting what reprofiling actually means? It takes me a couple hours at minimum to completely resharpen a blade including reprofiling.

3. Why is my bevel wider on one side of the blade compared to the other? How is this possible if I'm using the same angle on each side?

4. Using the edge pro do you change he amount of pressure you are applying while sharpening? Could this be why it takes me so long to reprofile? I don't put use much pressure if any on my 120 stone and up. Should I be pushing harder?

Super frustrated. Thanks.
Click to expand...

1. The argument will go on forever about what cuts better, polished or toothy, but it's your call. If you like the way polished edges perform and/or look, then go for it and don't let anyone dissuade you. On the other hand, a 400 grit EP edge will cut excellently. It's your knives, and if you want to spend the time and practice going for a perfect mirror and seeing how possibly sharp you can get a knife, then go for it. Sharpening is just part of the hobby for me, so I think it's fun although along the way you'll have your frustrations.

2. Depends on factory angle and goal angle. 18 dps from a factory 20 dps is going to be a lot quicker than a goal of 15 dps. If you care about doing a good job and are concerned with not forming a huge burr, then the time involved getting there shouldn't really matter. Take small breaks along the way. Just be glad you're using an EP to reprofile and not a Sharpmaker. Now if you want to talk about some time and frustration involved, try standing there for hours over a Sharpmaker, and I don't care if you've got stones rubber banded around the rods or not. Been there and won't ever do that again. I think the longest it's ever taken me to set a new angle with both sides completely apexed is 2 hours, and that was an M4 Gayle Bradley at 15 dps taking a few small breaks and checking the edge often with a loupe to track my progress. And I probably took another hour going up through the grits before finishing at 0.5u. In the end, it was absolutely worth it, to me...it may be the best performing knife I own. Some people will get a haughty attitude that they're not going to stand there for hours working on one knife and can have it "plenty sharp" in 15 minutes. Well, that's good as they, you, and I all have free will to spend our time however we want.

3. Blade edge not ground evenly in the center of the blade. I think the worst instance I've seen on my knives was a Ritter Mini Grip. Much wider on one side. I've had better luck with Spydercos and the Sebenza I'm working on currently seems to be well centered. If you've got a smaller bevel on one side, just hit it a little more on subsequent sharpenings, and eventually it'll even out.

4. I generally let the stones do the work. I think Ben Dale recommends something like 3 lb of pressure, but how do you know what 3 lb feels like? If you push too hard you could end up tilting the blade downward, changing the angle you're hitting the apex at. Once I feel like I'm "done" at a particular grit, I will use light pressure, decreasing strokes on both sides to minimize the burr as much as possible for the next grit. Maybe like 6, 6, 4, 4, 2, 2, 1, 1. YMMV but it works very well for me. When using nanocloth strops at the very end, I use no more pressure than gravity.

I think most everyone is frustrated when first learning sharpening. Patience and practice is all it takes. If you've got some free time and $5, go to Walmart and buy some cheap kitchen knives and practice. This way you can try a lot of different things and don't have to worry about messing up a good knife.
 
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