Will cutting a food releasing groove in a knife with a water cooled dental handpiece damage a knife?

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Just finished cutting the groove. Still need to smooth and polish. It’s hard to take a choil shot.
 

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Amazing! Looks like @Yoshi underestimated the steady hand of a dentist!
I'm indeed very impressed. Surprised that you've chosen a Shindo for this experiment, but I supposed the super low cost is a big plus.

That said I'm not sure how much better the good release will be, given that it's quite a bit of height between the edge and the groove. Also it's at where the previous hollow. My guess is you will not see much of a difference at all. Furthermore your pinch grip area is going to be quite sharp. For your next one (I'm sure you ain't gonna stop at one), you can grind it just in the middle (i.e not the full length of the edge), you will see what I mean if you look at Bidinger's knife. The rationale is that you don't need food release at the very tip nor the very end of the heel where your pinch grip is. That way you avoid shaving too much weight off.
 
I'm indeed very impressed. Surprised that you've chosen a Shindo for this experiment, but I supposed the super low cost is a big plus.

That said I'm not sure how much better the good release will be, given that it's quite a bit of height between the edge and the groove. Also it's at where the previous hollow. My guess is you will not see much of a difference at all. Furthermore your pinch grip area is going to be quite sharp. For your next one (I'm sure you ain't gonna stop at one), you can grind it just in the middle (i.e not the full length of the edge), you will see what I mean if you look at Bidinger's knife. The rationale is that you don't need food release at the very tip nor the very end of the heel where your pinch grip is. That way you avoid shaving too much weight off.
I chose a 165mm santoku because of the shorter length and I thought cutting carbon steel would be easier than stainless. I still have a Shindo gyuto and nakiri as a backup.
You are correct, the food release didn’t change at all, not any better nor any worse. I chose that area because the metal was thicker. I was thinking of modifying the same knife but closer to the cutting edge. I marked the area with a blue line. Only thing is the steel is only about 1.5 thick, so the hollow will be shallow (maybe .75mm). Any advice would be appreciated. I’m just doing this for fun, maybe I’ll get lucky and food release will improve. I’ll probably end up ruining this knife but I have a couple of S grind knives on the way.
 

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I chose a 165mm santoku because of the shorter length and I thought cutting carbon steel would be easier than stainless. I still have a Shindo gyuto and nakiri as a backup.
You are correct, the food release didn’t change at all, not any better nor any worse. I chose that area because the metal was thicker. I was thinking of modifying the same knife but closer to the cutting edge. I marked the area with a blue line. Only thing is the steel is only about 1.5 thick, so the hollow will be shallow (maybe .75mm). Any advice would be appreciated. I’m just doing this for fun, maybe I’ll get lucky and food release will improve. I’ll probably end up ruining this knife but I have a couple of S grind knives on the way.
I love how you have polished the previous groove, looking much nicer.

Your new line is much closer to the bevel, and should in theory offer you slightly better food release. If anything is going to turn it into a hook grind instead of a s grind. But again it might just be a small margin that you will gain.

Also I'm not sure it'll be that easy to pull off this time, that part is super thin, and you run a big risk of warping. So go slow and keep measuring the depth as you do. You can probably aim to take less depth than your previous groove to improve the success rate.
 
I chose a 165mm santoku because of the shorter length and I thought cutting carbon steel would be easier than stainless. I still have a Shindo gyuto and nakiri as a backup.
You are correct, the food release didn’t change at all, not any better nor any worse. I chose that area because the metal was thicker. I was thinking of modifying the same knife but closer to the cutting edge. I marked the area with a blue line. Only thing is the steel is only about 1.5 thick, so the hollow will be shallow (maybe .75mm). Any advice would be appreciated. I’m just doing this for fun, maybe I’ll get lucky and food release will improve. I’ll probably end up ruining this knife but I have a couple of S grind knives on the way.
The bevel / blade road looks pretty flat based upon your previous choil shot, so I don't really think that grinding in a second groove will do much, because the majority of ingredients will just bridge the gap and continue riding up the blade. To maximise food release, you really need to combine the food release groove with either some convexity or a hollow section, so that whatever you are cutting does not come back into contact with the blade once it crosses the groove. This could also be achieved by cutting in a wider groove, which gives the food more of a chance to separate from the blade before it makes contact with the other side of the groove.

Both the narrow food release groove combined with convexity or a hollow section and the wider food release groove force the food to separate from the blade as it crosses the groove, allowing gravity to overcome whatever forces are causing the food to stick to the blade.
 
The bevel / blade road looks pretty flat based upon your previous choil shot, so I don't really think that grinding in a second groove will do much, because the majority of ingredients will just bridge the gap and continue riding up the blade. To maximise food release, you really need to combine the food release groove with either some convexity or a hollow section, so that whatever you are cutting does not come back into contact with the blade once it crosses the groove. This could also be achieved by cutting in a wider groove, which gives the food more of a chance to separate from the blade before it makes contact with the other side of the groove.

Both the narrow food release groove combined with convexity or a hollow section and the wider food release groove force the food to separate from the blade as it crosses the groove, allowing gravity to overcome whatever forces are causing the food to stick to the blade.
Cutting the metal was faster than I thought it would be. Heat build up was minimal (I immediately touched the cut portion of the knife after cutting and I felt no heat. I think it was hot during the cut but it quickly dissipated due to the thinness of the knife and the small contact area ~2mm). I couldn’t detect any warping but it would have to be pretty obvious for me to see it. I don’t see half the things that more experienced members are aware of when talking about knife geometry and choil shots.
You’re correct, making a second groove probably wouldn’t help so I’ll widen the original hollow towards the cutting edge. I tried to avoid a wide hollow initially because the flat cutting surface of the bur is only 2mm and it’s hard to maintain an even flat surface. Wrong tool for the job but I’ll try it out. How thin can I go before I ruin the knife? I was thinking about 0.75mm.
 
Cutting the metal was faster than I thought it would be. Heat build up was minimal (I immediately touched the cut portion of the knife after cutting and I felt no heat. I think it was hot during the cut but it quickly dissipated due to the thinness of the knife and the small contact area ~2mm). I couldn’t detect any warping but it would have to be pretty obvious for me to see it. I don’t see half the things that more experienced members are aware of when talking about knife geometry and choil shots.
You’re correct, making a second groove probably wouldn’t help so I’ll widen the original hollow towards the cutting edge. I tried to avoid a wide hollow initially because the flat cutting surface of the bur is only 2mm and it’s hard to maintain an even flat surface. Wrong tool for the job but I’ll try it out. How thin can I go before I ruin the knife? I was thinking about 0.75mm.
It would be a lot of work, but looking at your first groove, my impulse would be to cut a second, shallower groove just below it, then another, shallower one yet … to form a decaying sine-wave ringing pattern ending as close to the edge as you can or dare go.

Since you’re denying even pliant ingredients a flat or large-radius surface to glom onto, you should get a clear difference in food release behavior.

The graph shows what I’m thinking, with amplitude exaggerated for clarity (and I’d choose a faster damping coefficient!)

By the looks of things, you should be able to grind another four advancing grooves before running out of ferrous real estate.
1720551743946.png
 
Making a hook grind is quite complex, and if the knife is not designed with that in mind from the start, it's complex to turn a flat grind into a hook grind.
To be efficient, the hook needs to be much closer to the cutting edge than where you did your groove. plus, the upper part of the blade needs also to be thinner , otherwise the food will just cross the gap and stick to the upper part of the knife.

Here, have a look at my knife:
Thanks to the damascus layering, you can see that the grinding angle is more important below the hook, than in the upper section. Therefore, the cut food has 0 chance of coming back in contact with the upper section. Which is in fact what you need, This is why Bidinger makes an s grind above the groove.


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It would be a lot of work, but looking at your first groove, my impulse would be to cut a second, shallower groove just below it, then another, shallower one yet … to form a decaying sine-wave ringing pattern ending as close to the edge as you can or dare go.

Since you’re denying even pliant ingredients a flat or large-radius surface to glom onto, you should get a clear difference in food release behavior.

The graph shows what I’m thinking, with amplitude exaggerated for clarity (and I’d choose a faster damping coefficient!)

By the looks of things, you should be able to grind another four advancing grooves before running out of ferrous real estate.
View attachment 334111
You’re too smart for me, I had to read your post several times to understand it, kind of like reading a textbook. I’l try it out, if it doesn’t work, I’ll flatten it out to a single flat hollow. Thanks
 
Making a hook grind is quite complex, and if the knife is not designed with that in mind from the start, it's complex to turn a flat grind into a hook grind.
To be efficient, the hook needs to be much closer to the cutting edge than where you did your groove. plus, the upper part of the blade needs also to be thinner , otherwise the food will just cross the gap and stick to the upper part of the knife.

Here, have a look at my knife:
Thanks to the damascus layering, you can see that the grinding angle is more important below the hook, than in the upper section. Therefore, the cut food has 0 chance of coming back in contact with the upper section. Which is in fact what you need, This is why Bidinger makes an s grind above the groove.


View attachment 334135
I attempted to thin above the hollow but it wasn’t enough. I’ll thin it above the hollow to the spine this weekend when I have more time. That’s a beautiful knife.
 
You’re too smart for me, I had to read your post several times to understand it, kind of like reading a textbook. I’l try it out, if it doesn’t work, I’ll flatten it out to a single flat hollow. Thanks
Sorry about the chewy content. It’s my nature.

Think of ripples: near-constant wavelength; diminishing contour.

water-drop-falling-into-water-surface-with-ripples.webp
 
Making a hook grind is quite complex, and if the knife is not designed with that in mind from the start, it's complex to turn a flat grind into a hook grind.
To be efficient, the hook needs to be much closer to the cutting edge than where you did your groove. plus, the upper part of the blade needs also to be thinner , otherwise the food will just cross the gap and stick to the upper part of the knife.

Here, have a look at my knife:
Thanks to the damascus layering, you can see that the grinding angle is more important below the hook, than in the upper section. Therefore, the cut food has 0 chance of coming back in contact with the upper section. Which is in fact what you need, This is why Bidinger makes an s grind above the groove.


View attachment 334135
This is an excellent description of the geometry and function. Thanks 👍
 
I attempted to thin above the hollow but it wasn’t enough. I’ll thin it above the hollow to the spine this weekend when I have more time. That’s a beautiful knife.
The trick is to drastically thin above the groove. And if you want to be perfect, regrind below the groove: put more angle, or make a concave grind ;)
 
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I added more grooves and widened the hollow area so that there would be less surface area for food contact. I tested it out and the food release was slightly improved. Since I perforated the knife and basically ruined it already, I decided to cut out a large window in the knife where the perforation is. This is getting ridiculous, but I’m curious if food release will improve because there really isn’t much contact area. I’ll test it out later on when I go home. This experiment is over, it was a failure. Even if food release is excellent, the knife is too flimsy now and it’s freaking ugly.
 
View attachment 334768View attachment 334770View attachment 334769I added more grooves and widened the hollow area so that there would be less surface area for food contact. I tested it out and the food release was slightly improved. Since I perforated the knife and basically ruined it already, I decided to cut out a large window in the knife where the perforation is. This is getting ridiculous, but I’m curious if food release will improve because there really isn’t much contact area. I’ll test it out later on when I go home. This experiment is over, it was a failure. Even if food release is excellent, the knife is too flimsy now and it’s freaking ugly.
I would not call it a failure.
 
View attachment 334768View attachment 334770View attachment 334769I added more grooves and widened the hollow area so that there would be less surface area for food contact. I tested it out and the food release was slightly improved. Since I perforated the knife and basically ruined it already, I decided to cut out a large window in the knife where the perforation is. This is getting ridiculous, but I’m curious if food release will improve because there really isn’t much contact area. I’ll test it out later on when I go home. This experiment is over, it was a failure. Even if food release is excellent, the knife is too flimsy now and it’s freaking ugly.
Some things can only be learned through experience, lmao.
 
View attachment 334768View attachment 334770View attachment 334769I added more grooves and widened the hollow area so that there would be less surface area for food contact. I tested it out and the food release was slightly improved. Since I perforated the knife and basically ruined it already, I decided to cut out a large window in the knife where the perforation is. This is getting ridiculous, but I’m curious if food release will improve because there really isn’t much contact area. I’ll test it out later on when I go home. This experiment is over, it was a failure. Even if food release is excellent, the knife is too flimsy now and it’s freaking ugly.
Karol Karyś applauds you 😆

I admire your stamina in this project. Nice going
 
View attachment 334768View attachment 334770View attachment 334769I added more grooves and widened the hollow area so that there would be less surface area for food contact. I tested it out and the food release was slightly improved. Since I perforated the knife and basically ruined it already, I decided to cut out a large window in the knife where the perforation is. This is getting ridiculous, but I’m curious if food release will improve because there really isn’t much contact area. I’ll test it out later on when I go home. This experiment is over, it was a failure. Even if food release is excellent, the knife is too flimsy now and it’s freaking ugly.
I wager you’re the first kid on the block to have a Shindon’t.
 
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