Tweaking edge thickness

[captaincaed]

I've got a new knife I'm trying to figure out. All the measurements tell me it should cut well, but it's a bit sluggish. Not wedging badly, but ... sluggish.
Western gyuto, 224 x 51mm, 3.02mm at the spine. Thickness 6mm behind the edge is nearly same as my Yoshikane, 0.083mm vs. 0.078.

My one observation is that the Yoshikane is nearly a zero grind with an imperceptible primary bevel. The new knife has a "western" primary bevel, 0.6-0.7mm wide.

For those who sharpen more often, would rounding the 'shoulder' between the primary and secondary bevel help cutting ability (right now, it's a bit of a hard transition when I run my thumb nail over it), or is this a case for a more serious thinning? I don't have a cheaper knife with comparable geometry I can experiment on.

I'm leaving names out right now.

Thanks for the insights

 

[M1k3]

I would start with the shoulders. Add convexity also.

 

[captaincaed]

Thanks Mk. I'm also realizing the blade gets thicker toward the tip. I might contact the maker. Need to try a couple things first tho.

 

[panda]

make the primary bevel even bigger (raising a baby shinogi essentially) and then ease the shoulder. it will cut considerably better after. what this does is an inbetween a major thinning, so more like a medium thinning.

 

[captaincaed]

Gotcha. The steel is stupid hard, might take a hot minute.

 

[TSF415]

I don’t know nearly as much as others when it comes to sharpening but I’ve had a similar situation. What worked for me was to just thin right behind the edge basically just until the bevel disappeared (probably at 8-10degrees) and the just put on a new much thinner cutting bevel.

 

[stringer]

I've got a new knife I'm trying to figure out. All the measurements tell me it should cut well, but it's a bit sluggish. Not wedging badly, but ... sluggish.
Western gyuto, 224 x 51mm, 3.02mm at the spine. Thickness 6mm behind the edge is nearly same as my Yoshikane, 0.083mm vs. 0.078.

My one observation is that the Yoshikane is nearly a zero grind with an imperceptible primary bevel. The new knife has a "western" primary bevel, 0.6-0.7mm wide.

For those who sharpen more often, would rounding the 'shoulder' between the primary and secondary bevel help cutting ability (right now, it's a bit of a hard transition when I run my thumb nail over it), or is this a case for a more serious thinning? I don't have a cheaper knife with comparable geometry I can experiment on.

I'm leaving names out right now.

Thanks for the insights

Really thick primary bevels are very durable. They work fine for slicing sharpness but aren't great at push chopping sharpness. I would do like Panda said. Raise the shinogi until you have a faux wide bevel and then put a new tiny primary bevel. I had to go through this process when I bought my Shi.han. After I thinned it it had a much better feeling going through food. Especially in cut initiation. You sacrifice some durability, but the knife also becomes much easier to sharpen and keep sharp.

https://www.kitchenknifeforums.com/threads/durability-testing-shi-han-aka-ginrei-240-gyuto.42530/

 

[captaincaed]

This beast is full satin convex, not sure where to start building a shinogi from with only stones on hand. I do like that idea though. Stringer are you refinishing with any power tools or are you 100% bench stones?

I may try to work up from the edge as Panda suggested, for the time. I can always remove more if I need to later.

 

[Cliff]

I did this recently with a 140 Atoma. It took awhile, but performance got much, much better. I can't say the polish I did after that is a thing of beauty, but it is more than okay for me. If you are concerned about the deep scratches, get a really low grit stone. At a similar grit rating, they will do less damage to the finish than a diamond plate.

 

[soigne_west]

I thought nutmegs technique was pretty interesting

 

[stringer]

This beast is full satin convex, not sure where to start building a shinogi from with only stones on hand. I do like that idea though. Stringer are you refinishing with any power tools or are you 100% bench stones?

I may try to work up from the edge as Panda suggested, for the time. I can always remove more if I need to later.

95% bench stones. I do have a 1X30 belt sander that I use occasionally. But usually only for crap stainless or softer carbon steels.

For coarse stones I have a Debado 200, a Crystolon coarse, and a King 300. The Crystolon is probably my favorite, but the Debado is growing on me.

 

[Boynutman]

Just a thought, haven’t seen the knife nor do I know its history, but could surface roughness after thinning play a role here?
I noticed this can make a significant difference.

 

[M1k3]

Just a thought, haven’t seen the knife nor do I know its history, but could surface roughness after thinning play a role here?
I noticed this can make a significant difference.

That would explain it if the knife wasn't wedging also. The first 2 cuts of his video, you can really hear it.

 

[M1k3]

95% bench stones. I do have a 1X30 belt sander that I use occasionally. But usually only for crap stainless or softer carbon steels.

For coarse stones I have a Debado 200, a Crystolon coarse, and a King 300. The Crystolon is probably my favorite, but the Debado is growing on me.

If you like the Crystolon, you'll probably like the Shapton Pro 120.

 

[captaincaed]

I also like Norton stones. Feel terrible but do the job. Cut anything.

I haven't done any work yet, so surface texture is stock. It's got some suction I hope will decrease as patina gets better. Grind is a bit convex but fairly flat.

Current thought based on my stone inventory is raise the primary bevel a bit with a Gesshin 220, smooth and round shoulders with my 1k, then try to get the satin finish back with one - way sandpaper rub (when I hear what the grit is from the maker). Should be a fun little project.