natto
Senior Member
Yes, my point was about geometry. But anywayOops .. the suggestion from Fourty Ounce was the main one that was tried here.
??? Would you mind to explain?Togitogi
Yes, my point was about geometry. But anywayOops .. the suggestion from Fourty Ounce was the main one that was tried here.
??? Would you mind to explain?Togitogi
Yes, my point was about geometry. But anyway
[snip]
Sorry, poor english here. But you are right. I was not sure wether you got the whole picture. Nice to hear you got it.Hopefully that clarifies, Thanks again.
Are you alternating between the back and front when deburring?Next question ...
I think I have the bevel geometry about right. I am having some trouble removing all the roughness (micro-chips) at the edge. I have noticed that I can sharpen on a 1000 grit, feel an even burr, and remove it (ura with 8000 grit), yet the edge isn't clean. It is hard to even see the problem until I go to finer grit, so it's taking a lot of time. A microbevel doesn't remove it (because I wasn't going to make it more than micro). I have been over it 3 times already, and it may be improving. It is cutting cleaner each time. I haven't gone back to a courser stone because I was afraid of making it worse. Suggestions? Otherwise, I'll just keep going on this path until I get it. Latest picture below, but I don't really have a good way for you to see the rough edge, and anyhow, you know what that looks like.
View attachment 171015
Are you alternating between the back and front when deburring?
That's good news.I have been over it 3 times already, and it may be improving.
It kinda sounds like you just have some residual burr left. This is a guess, ofc, since I can't check it out in person, but I'd keep going and see if it improvesYes.
Almost always on 8000 grit for the ura. I used a 3000 once after the initial rework because the edge was worse.
For better or worse, I cleaned up the edge with microbevel, which I then polished. The microbevel is larger than I prefer (for single bevel). I think the knife can be used as-is for now. As I get more inspiration or ideas, I can see if it sharpens normally.
Dunno that I'd recommend that deba video.. Korin vids tend to not be great.That's good news.
Heat treat on the hard side not only allows micro chipping. The chips might indicate micro cracks. And cracks can grow further up. It's just one way to look at this compromised materal above the edge.
I checked this on my double bevel. It took some serious sharpening to get rid of this problem. Touch ups or usual sharpening didn't work. The knife is a Mizuno white 2, so nothing crazy hard.
Good news is, after removing compromised material the knife improved. My initial sharpening didn't remove enough material.
And Korin got a vid, mentioning ura sharpening and brittle edges.
Learn How To Sharpen: Episode 11 - Deba Basics
I follow Jon technique in his sharpening video on YouTube, so far everything is good, great vendor!Dunno that I'd recommend that deba video.. Korin vids tend to not be great.
I think so too. At least with a clean microbevel, now I can more clearly see what I am doing. Hopefully, the micro chips/cracks have been ground off. If they reappear, I will have to re-evaluate. I have been following Jon's (of JKI) videos.It kinda sounds like you just have some residual burr left. This is a guess, ofc, since I can't check it out in person, but I'd keep going and see if it improves
I can't re-temper it. Maybe just sell it.
I have a new-ish single bevel knife, and a question on sharpening.
The knife, as new, was ground so badly, I sent it off for professional help. They did a good job of fixing the major problem: the entire flat section had a significant frown. It may have had other issues, but it was hard to tell with the frown. The knife came back with the frown gone, and nice flat surfaces (no concave spots).
By flat, I meant the side profile, not the bevel.I have a question about this. Shouldn’t the flat side be concave with traditional knifes? It shouldnt be flat flat. Right?
I sent it off to be professionally repaired. The frown was fixed, but it was so thick behind the edge, it was worse that useless.
Seems pretty close to your problem on a Suisin blade. I am aware that Sakai Takayuki (Aoki hamono) is different from Suisin (Junro Aoki & Son), but are they somehow related? Was the grind "error" intentional? Could there be something lost in translation somewhere, like their own style of hamaguri or something?
I don't mean to knock anyone, but personally I would not send a complex job like this to a retail shop. Mate, how about sending your knife to CO? It'd be interesting what Yosuke-san can come up with...
Before you do that.. send it to me and I'll see if I can put an edge on it. If you pay for shipping, I won't charge ya.I can't re-temper it. Maybe just sell it.
That's very generous of you. I'll message you shortly (next couple days).Before you do that.. send it to me and I'll see if I can put an edge on it. If you pay for shipping, I won't charge ya.
Have you checked the blade for straightness? The coarse feeling could be from it being bent.More questions .. and not signaling anything different from what I said.
I still don't know where the micro-chips at the edge post-sharpening are coming from.
What should the edge look like before applying a microbevel? It's effectively a razor edge, but I have never gotten it "perfect". Specifically, I can see shiny spots on the edge in bright light (after burr removal from ura work). Before the ura work, it's hard to be sure what I am looking at because of the burr.
What should I expect to feel while doing the ura? I have a couple stones of 8000 grit and above I have tried, all carefully flattened and clean. I try to use just enough pressure to keep the blade flat and not hydroplane. I get a sensation that feels a little rough. I could imagine bits of burr on the surface. Cleaning the stone and repeating doesn't change anything much. What is expected about water/slurry on the stone during the process? The first pass towards the edge acts like a squeegee.
I wonder if applying the microbevel is causing damage to the edge. I use a very light pressure; I can't imagine less, and still have proper angle and pressure control. Whether I use a 5000 or 8000+ grit didn't seem to matter. Is it correct to start at the final angle you want? That's what I have been doing. I can imagine steaking up on it, but I think I would get a wide round "less-micro" bevel.
Well.. that sucks. Good news though, I can fix that easily (again, no charge)Interesting. I set the ura on the backside of my Atoma, and there's at least 1 mm (could be 2, just eyeballed it) deflection away from the Atoma. I was careful to place the heel at the edge of the Atoma, so this isn't due to something funky near the handle.
Well.. that sucks. Good news though, I can fix that easily (again, no charge)
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