Overgrind or something else? What to do?

[mrmoves92]

Hello!

I bought this Mutsumi Hinoura stainless clad AS 240mm gyuto about three months ago. The original owner bought it from Cleancut, sharpened it, briefly used it, and then sold it to me.

I have used the knife to cook numerous meals since purchasing it. After a few meals, I stropped the knife, and I noticed that the edge bevel/thickness looked a bit uneven, and in one spot especially, it looked like it could have been overground there and that the edge wasn’t really there. It wasn’t really noticeable in use.

Yesterday, I touched up the edges on most of my knives. My stones were flat (at least reasonably flat. I did the pencil thing and used a diamond plate). Touching up the edge went really well on all of my other knives, except this one. Touching up this knife helped on most of the edge, but it didn’t get as sharp as my other knives (probably because I haven’t gone through a full sharpening progression with this knife yet), and there were two sections of the edge where touching up did not seem to help much at all. Also, the edge thickness at and just in front of the heel also seemed especially thick. This could have been a little bit my fault, but I don’t think that I changed my sharpening angle that much at the heel. I didn’t have any similar issues around the heel on any of my other knives.

Here are pictures of what the two spots look like with red arrows pointing to the problematic spots:

Zoomed in:

Here are my questions:
Do these two spots look like overgrinds? Does the heel seem thicker, or do you think that it was a sharpening mistake by me? What would you do in this situation? Would you sharpen the edge until those two spots are no longer problematic? Would you grind out the low spots from the primary bevel? Something else?

Thank you for your help!

 

[Vamtal]

It is common that the factory Kireha (primary grind) is not perfectly flat. If the edge is flat or slight belly around these problemathic areas, then everything is fine. (internal curve of the edge is bad ... it is necessary to grind edge until internal curve is gone)

Don't worry. These are just cosmetic issues that disappear with the first thinning and proper kasumi polish.

 

[RDalman]

First check that the knife looks straight, small straightening occasionaly might be needed with san mai knives. Then what @Vamtal said just sharpen post the unevennes should fix the issue.

 

[Bensbites]

I would check for board contact. If those areas touch the board when cutting, then you are fine. If those areas show daylight and can’t touch the board, then you have some work to do.

 

[Benuser]

You've got all excellent advices here. About the heel: it is very common to have a more or less abrupt thickening, which results in a wider bevel if the same angle was used along the entire blade.

 

[Pie]

I would check for board contact. If those areas touch the board when cutting, then you are fine. If those areas show daylight and can’t touch the board, then you have some work to do.

If you’re like me and can’t see worth a damn, whether the spots are a problem or not can be determined by a burr. If it’s not making contact, it’ll be hard to take the burr off or flip it over in those spots.

Maybe some inconsistency in the grind, hopefully not enough to make a hole where your edge should be tho.

 

[Benuser]

Only a good sharpening, started by some thinning, can tell.