Raised Lamination Line

[schools out]

Recently I picked up a Masakage Koishi used, the lamination line where the steels meet in the grind is raised on the cladding steel. This is the first time I have experienced this, I can actually catch my finger nail on it if running from the blade edge. Is this normal? I assume it could be removed through a thinning session.

Thanks!
Nick

[Jeff B]

Sounds like it has started to delaminate or has a void in the weld but no, it's not normal. Thinning may get you past the problem area or may not.

[Altadan]

Can you capture that on a photo?

[ChefKnivesToGo]

Yes please show us a picture. I'll bet it's a tiny air bubble that made a gap between the edge steel and the cladding. If that's the case a thinning session or two will most likely remove it.

[schools out]

I had a hard time taking a pic so you can see it. Not isolated to one spot or any gaps between layers. Just a noticeable edge. Like the cladding sits on top rather than a smooth transition with the grind. This runs the entire length on both sides.

[milkbaby]

That picture makes me think it was etched. The carbon steel core turns dark and etches away quicker while the stainless core resists the etch staying bright and not dissolving away as quickly in the acid. That would account for the height difference you can feel with your fingernail.

[delmar]

Personally, I'd lay it down on the bevel and do a mock thinning on a medium grit stone and see if that starts to pull the step out. If so, then I'd get a bit more aggressive on a lower grit like a true thinning and run with it like Mark said.

[pd7077]

That picture makes me think it was etched. The carbon steel core turns dark and etches away quicker while the stainless core resists the etch staying bright and not dissolving away as quickly in the acid. That would account for the height difference you can feel with your fingernail.

That was my first thought when I saw the photo as well

[schools out]

600 - 1000- 3000 - 8000

I thinned it for a while this morning removing most of the stepping on the lamination line. I didn't remove all of it because I was starting to really remove material and had to stop and re-profile a couple time. But 95% is flat and the rest is near flat.

Heres a couple pics of the entire line and some that I decided to leave.

Before


During


After



Thanks for all the help!
Nick