What does it look like at each grit - AKA Sample Scratch Patterns

M

malaverdiere

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Oct 3, 2016
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I'm a newbie sharpener with a Lansky guided angle system (w/ artificial stones) as well as a cheap-EdgePro-wannabe with diamond hones.
I've read the good advice on this forum, and I've gotten much better, yet there is one thing from the advice that I'm not 'getting', and that's about the scratch pattern.

With either system, I'm left with a scratchy-looking edge after the 1000 grit stone. It will cut hair after a few strokes, but I wouldn't call that 'shaving sharp'.

In What is sharpening a knife about? (2015 updates!), Magnaminous_G says,
"It’s about when the scratch pattern is fully established (transferred from the stone onto the bevel, like an imprint), all the way to the edge, until spending more time on that stone would be a waste of time as one wouldn’t be changing anything but rather only removing more metal needlessly. So the thing to know is *when* that has happened and thus *when* to move to the next stone."

So, without a magnifying glass, what does that look like? For each major grit? (e.g. 70, 120, 280, 600, 1000, 2000, sky-is-the-limit)?
I'm guessing that knowing what to expect will help me reach the next level.
 
Wicked Edge has a Grit Comparison Chart of some of their diamond, chosera, and Shapton stones.

Not exactly what you're looking for, but does have pictures that'll give you an idea.
 
after my 1200 grit diamond stones i cannot see scratches with the naked eye, only a smooth semi polished surface.
 
malaverdiere said:
So the thing to know is *when* that has happened and thus *when* to move to the next stone."

So, without a magnifying glass, what does that look like? For each major grit? (e.g. 70, 120, 280, 600, 1000, 2000, sky-is-the-limit)?
I'm guessing that knowing what to expect will help me reach the next level.
Click to expand...
I doubt looking at online images will help that much. Nothing beats in-hand viewing. And beyond 1000, a magnifying glass becomes essential.

Take a practice blade and mark up the edge with a Sharpie. Start sharpening with your coarest stone. When the Sharpie is all gone, the grit pattern has mostly been established. Remark the edge with the Sharpie and sharpen with your next finer stone until the Sharpie is all gone. Progress through your stones, examining after each progression.
 
malaverdiere said:
(...)
So, without a magnifying glass, what does that look like? For each major grit? (e.g. 70, 120, 280, 600, 1000, 2000, sky-is-the-limit)?
I'm guessing that knowing what to expect will help me reach the next level.
Click to expand...

Use a magnifying glass. ;)

Seriously, the best way to see the real difference with your own edges, using your own hones, is to closely inspect it as you go. It'll become obvious as you work, and especially so if using a good, well-lighted magnifier. You're not really looking for a specific appearance for each grit stage, but instead looking for a complete CHANGE in appearance from one grit to the next, replacing one scratch pattern with another across the full width of the bevels. It'll be easier to see the scratch pattern change from one stage to the next, with good magnification. In particular, if the scratch pattern isn't fully replaced across the full width of the bevels, you'll be able to see it under magnification (it's obvious and ugly, most of the time). With time and experience, it'll become easier to recognize these changes by naked eye as well. Even then, it's still useful to inspect with magnification, as it's very easy to stop short of fully replacing the scratch pattern all the way to the edge, often leaving a hair-thin portion unchanged immediately behind the apex.

There are way too many variables affecting how one particular grit's scratches should look, such as the steel type and it's individual hardness, the individual character of the stones/hones you're using (abrasive type, quality, density of coverage, wear, etc), and the pressure & technique used with them. Comparing to images online has never been useful to me, as it's impossible to know exactly what tools, materials and conditions created the images being viewed.

A well-lit 10X magnifier or better is very good for inspecting scratch patterns at the edge.


David
 
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The suggestion for a magnifier is a good idea. A loupe works really well and they are very inexpensive these days. To train yourself for later though, you might want to develop techniques that don't require extra tools to be used all the time. In this case, the reflected light technique can be pretty useful. Read my description here in Secret #4. Secret #4 itself is very important to sharpening IMHO.

Brian.
 
This + :thumbup:

Once you get used to looking and seeing what's there with no magnification, you'll be surprised what sorts of issues you can diagnose with no magnification (though I still recommend magnification at first, 6x-12x are best IMHO).

The issue with leaning on the magnification is you tend to miss the macro stuff like shifts in your angle control.
 
Thanks everybody. I dug in my box-of-unused-stuff and fished a 8x magnifier. I like what I see already, though I doubt this is enough to catch the "leaving a hair-thin portion unchanged immediately behind the apex."

As for secret #4, do you have a link to a video? Because I'm not 'getting' it right now :(
 
malaverdiere said:
As for secret #4, do you have a link to a video? Because I'm not 'getting' it right now :(
Click to expand...

Seven Secrets was originally going to be a video series. But I never made the time to do it, so I wrote it up instead. Are you "not getting" the overall concept of Secret #4, or are you just not getting how to use the reflected light technique?

Brian.
 
I use a 30x loupe and find it to be barely enough to see what's going on. Using a USB microscope would be the best option IMO and is what really helped me understand what was happening at the edge. Right around 200x is where you really start to see what is going on. I also found it very helpful to feel the edge after viewing the photo, this gave me an excellent reference point for future sharpening's and allowed me to move past frustrating sharpening issues by feeling what was wrong.
 
bgentry said:
The suggestion for a magnifier is a good idea. A loupe works really well and they are very inexpensive these days. To train yourself for later though, you might want to develop techniques that don't require extra tools to be used all the time. In this case, the reflected light technique can be pretty useful. Read my description here in Secret #4. Secret #4 itself is very important to sharpening IMHO.

Brian.
Click to expand...

Secrets to blade sharpening success in one place. Well done Brian - a very useful read. Thanks for taking the time. :thumbup:

Ray
 
bgentry said:
Seven Secrets was originally going to be a video series. But I never made the time to do it, so I wrote it up instead. Are you "not getting" the overall concept of Secret #4, or are you just not getting how to use the reflected light technique?

Brian.
Click to expand...

The reflected light technique. I am seeing lots of interesting things with 8x magnification that I'm not noticing with reflected light only.
 
malaverdiere said:
The reflected light technique. I am seeing lots of interesting things with 8x magnification that I'm not noticing with reflected light only.
Click to expand...

You'll definitely see more with a magnifier than with the naked eye. The reflected light technique will show you things that you wouldn't normally see, but it's not like using a loupe or a magnifying glass.

Here's something you can try with reflected light: Hold your blade with the left or right side up. Angle it around until you get light to bounce off of the edge bevel on that side of the blade. The edge bevel is probably 1/16" to 1/8" wide. You'll see a nice bright line reflected there when you do this right. Now, move the blade slightly so that the reflection moves up towards the tip of the blade, but stays on the edge bevel. Change the angle back the other way and watch the light move back towards the heel of the blade, but still shining on the edge bevel.

What does this show you? First, you'll notice that the width of the reflected light "line" changes where the edge bevel changes width. It's kinda hard to see the difference between 1/16" and (for example) 3/32" with the naked eye. But with reflected light, the difference is much easier to see. This can help you find the areas of the blade that are ground inconsistently.

Second, depending on the exact angle and the brightness of the light, reflected light can show you the scratch pattern much more clearly than the naked eye. Move the blade around and watch how the metal changes in look as you get more and less light on it. This can help you identify how coarse (or fine) the scratch pattern is. Again, magnification will show you more. But reflected light is better than just the naked eye without any assistance.

I'm not sure if this helps, but I hope it does.

Brian.
 
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