Grinds and Heat Treat

[Kerneldrop]

What characteristics make a grind excellent or good?
I read through some of the CKTG product descriptions and see "excellent grind", "great grind", "good grind", "good grind for the price", etc...
And in some forum posts I have seen " knife x has better grinds"

And part two:
How can one tell when a knife has a hard heat treat, or a quality heat treat?

[aporigine]

What characteristics make a grind excellent or good?
I read through some of the CKTG product descriptions and see "excellent grind", "great grind", "good grind", "good grind for the price", etc...
And in some forum posts I have seen " knife x has better grinds"

And part two:
How can one tell when a knife has a hard heat treat, or a quality heat treat?

I’m not very far along in my Jknife adventure, but I’m beginning to think it is as subjective as “what makes for a great car?”.

It depends greatly on what you prep and what your style is.

A great grind is one that goes very nicely through the ingredients you usually cut. If you’re like me, who has low volume, soft ingredients and never encounters a hard cutting board, a winter squash or a bone-in chicken, a laser is sure to please — disclaimer! I have some midweights that do surprisingly well on a russet potato or a peeled onion, but for me the type specimen of a great all-‘round grind is my Shibata Kashima. The way it drops through a fat russet is a special experience.

Conversely, my single-bevel sushi blades are a joy on raw fish, but useless on a potato, and likely to chip like a (!) on an unpeeled garlic clove. “Horses for courses.”. A high-volume power player in a pro kitchen will have very different answers. Hardness is a good news/bad news proposition. I like knives on the glassy-hard end of the spectrum, but with hardness comes lowered toughness. (Until someone offers a san-mai of adamantium in vibranium!) A pro facing six cases of veg for mirepoix cannot afford a blade that’ll cream through the first 10 lb, but take damage before the job is done! So a good pro workhorse will be detempered a bit for toughness. You probably won’t find ceramic blades on the line!

I do not know how much this helps. I’ve bought various knives and learned what works for me.

[Kerneldrop]

Thank you. I wasn't sure if the "grind quality" was an actual measurable quality or subjective....so, it seems, at least to a degree, it's subjective and just depends. I've been looking at the grind pics so I'm beginning to see the differences.

[taz575]

One of the things to look for is how cleanly the blade road is ground. If it's even and cleanly done, it's good. If it has some dips and ripples, it's something to consider and if you go to flatten or clean it up down the road, it may take a while. Some blade roads look flat, but may be convex or have an extremely shallow hollow grind to them, which can throw people off and have them think it's a bad grind. Many of these knives are hand ground on large stone wheels with the blade held in a wooden jig, so it's hard to see what it being ground. Dips and ripples are pretty common and generally don't cause any issues unless heavy re thinning/re grinding is needed.

People have preferences for different grinds for different foods. Some like a more robust workhorse, others like a laser. It's all about matching the grind to your preference!

Heat treating is harder to tell. If the blade sharpens well, holds an edge like it's supposed to and the edge doesn't chip out constantly, it's a good heat treat! Some steels sharpen nicer than others, so a harder to sharpen steel may be more wear resistant and some steels take a more toothy edge, so you need to know the characteristics of the steel. Rockwell hardness testers can be used, but near parallel and flat spots to test and if the blade is clad, it will read as soft since the cladding doesn't harden. Hardness files are another option, but not as accurate. Different blades can read the same hardness, but have completely different grain structure in them as well!

[Kerneldrop]

Thank you. I have seen blade roads in pics that look more clean and uniformed than others. And others look purposefully designed.
I've watched youtbe videos with the wooden jigs and grinders.
I didn't realize the sharpener does a lot of that, too. I had it in my mind the sharpener just putting the edge on the blade...but the videos I've seen the sharpener is using a wooden jig to finish grinding and then sharpening.
There's a neat video of Hirata Blacksmith's knife making process. He's a sword smith
and made a Santoku for the video.
A husband and wife team does all the work starting with sifting the iron-sand, making the Tama-hagane, all the way to final finishing.
Supposedly one of 3 that actually make their own steel.
https://mokomimi1027.wixsite.com/my-site-2
https://www.youtube.com/watch?v=ClBCQyMnXfw

[jmcnelly85]

A metric I like to use for assessing grind is accuracy. Not all nice knives brunoise an oversized carrot as effectively as others. Some makers try to get cute with wabi sabi and wind up making knives that tend to steer, whereas even a large knife with an exceptional grind can make easy work of garnishes and other precise cuts.

[taz575]

Sharpeners in Japan are the ones that typically do the final grinds and stuff. not just the edge sharpening. It's very confusing! Many blanks are forged out oversized and stamped out, then go to rough grinding, then to final grinding/sharpening. This is why some knives have the same profile from different brands; they used the same dies to stamp out the blade when it's soft after it's rough forged.

For some blades, usually the more machine finished blades (ie mass produced), it may be the same person grinding/sharpening them, but the more hand done stuff (like wide bevel blades) may have several people working on the knife to go through the processes! Very few Japanese smiths do the entire process themselves individually. Their name may be the brand or they may do the final sharpening, but they usually specialize in the areas that need to most skill and have others do other tasks, sometimes by an apprentice. The master may forge the blanks and then do the final grind and sharpening, another person does the rough grinding only and and older apprentice may assist in the forging, use the die to blank out the blades, do the straightening and heat treating with the master overseeing the processes. The apprentice may eventually shown how to do the blades in the masters style to carry on the name and characteristics of that brand/grind typically.

In the US, a custom maker usually does everything or almost everything start to finish. Some may get steel water jet cut out into the profiles they want and others farm out the heat treating (saves a lot of time and you know the heat treat is done right!), but usually it's one person doing the main grinding and work on the blade. Sometimes a shop assistant will prep stuff (drill, cut out scales closer to shape, rough grind handle scales, glue up handles/liners, etc) while the main person grinds the blades, shapes the handles and teaches the other one how to do it. Handles are easier than the blades are to do, so thats where they often start!

Most knife companies in the US use CNC or other machinery to make their blades, so there is very little hand work done to the knives. I got to visit Lamson when they were making the Artifex way back for Mark and their process was very hands off! Each person working at a station didn't really get to impact any personal flair; they were all nearly identical. Most larger factories are the same even in Japan, getting the work done consistently with little hands on. Bark River is one of the US companies that gets blades water jet out, cnc's the rough grind and the handle scales (on most materials), and then assemble the handle and does the final hand shaping/finishing of the handles and the blade grinds by hand, so there is more personal touch to the knives, but they are also very efficient.

I tried some carrot testing recently! The stepson likes carrots, so I cut them up so he has a healthy snack choice! Got some big ones to go through still, but they give good feedback!

First time I really did planks or matchsticks:
https://youtube.com/shorts/BN_e1A37_Pw? ... OZOm95LCT1

[Radar53]

I use a couple of ways to check out a grind.

First is a small "straight edge" eg the edge of a ruler. Place this perpendicular to the blade at intervals from heel to tip. Notice where there may be "hollows" in the blade and blade-road ie concave areas of the blade. Similarly, the ruler may "rock", which indicates convex areas of the blade. Some of these may or may not be intentional, but it starts to paint a picture. Step & repeat for the other side.

Secondly, I use my thumb & forefinger to "gauge" the blade & the usual care and attention is needed to ensure this done safely. I place my thumb and forefinger on opposite sides of the blade with the tips up close to the spine and the edge close to my hand (hope this makes sense!). Be careful. Then with even light pressure on both thumb & forefinger draw them to the edge of the blade trying to feel the profile beneath. Again, do this at intervals from heel to tip. With sight being our most dominant sense, it can sometimes help to close your eyes when doing this to block out the visuals. Again it can useful to change hands & repeat, just check if your first-side impressions are repeated.

This works quite well for me, but as always YMMV

[taz575]

For blades that are shinier, sometimes you can look down the side of the blade from heel to tip and look at the reflections on the blade:

It helps if there is something straight that is reflecting onto the blade to see the grind, but you can still see the hollow near the spine and convex towards the edge.

[ex1580]

For blades that are shinier, sometimes you can look down the side of the blade from heel to tip and look at the reflections on the blade:

heel to tip.jpg

It helps if there is something straight that is reflecting onto the blade to see the grind, but you can still see the hollow near the spine and convex towards the edge.

This is excellent advice!

[Kerneldrop]

So I’m assuming the more well-established blacksmiths use the better sharpeners, and with that comes better equipment and tools, and more skills.

Now i understand why the Konosuke Fujiyama line came to a stop until Myojin stepped in. I wondered why they couldn’t find someone else to put an edge on a knife. lol

I figured there was more to an edge when Steve would do a video, let’s say of a Shibata knife, and claim Shibata as one of the best sharpeners on the planet then give the edge a 6/10. So I’m guessing most knives aren’t finished on stones? I read where Okeya is hand-sharpened before being shipped…I’m assuming on whetstones.

I wonder what the real-world home-use difference is between a good Tosa grind, versus an excellent grind.

Yasunori claims to do his own forging, heat treat, grinding, edging. I’d like to check out his Santoku.
https://www.chefknivestogo.com/yasunoriknives.html