Knife Sharpening Thread

[ChefJohnBoy-ardee]

Ah yeah! There are certainly plenty of experts who do like to go up to 8k, though I quite like a edges a little less refined (or perhaps I don't want to risk rolling an edge on a fine stone and then having to go back ).

Funnily enough though - the only knives I do always finish very high are yanagiba, though that's probably because I'm polishing them as well. I have a few old yangi that I've restored, and spend far more time polishing them, and thinking about how pretty they are, than actually using them .

Spent probably 3 hours fixing a Kasumi finish on a knife i repaired for a former boss. He got a knew gyuto. His first japanese knife. He broke down a case of chickens with it. It looked like a serrated knife. I don't have a belt grinder.

I lit up a cigar, put a movie on the tablet and got to work. Got the profile right, had to figure out how far behind the she to thin it etc.

Two cigars and two movies later, the blade was fixed but the finish was marred from the repair. Another cigar and movie and I'm covered in mud from a jnat. Make mud, out on blade. Polish with cork and mud...

Yes I billed him for 7 hours of my day off labor. Knife looked good though.

 

[cotedupy]

Spent probably 3 hours fixing a Kasumi finish on a knife i repaired for a former boss. He got a knew gyuto. His first japanese knife. He broke down a case of chickens with it. It looked like a serrated knife. I don't have a belt grinder.

I lit up a cigar, put a movie on the tablet and got to work. Got the profile right, had to figure out how far behind the she to thin it etc.

Two cigars and two movies later, the blade was fixed but the finish was marred from the repair. Another cigar and movie and I'm covered in mud from a jnat. Make mud, out on blade. Polish with cork and mud...

Yes I billed him for 7 hours of my day off labor. Knife looked good though.

Jaysus, that's some proper dedication, kudos! What do you use for the kasumi/polish?

Here's my current old restored yanagi state of play. These were all mega rusty, chipped, tipped etc. when I got, none of them massively long, but I quite like them . Top two will never have perfect shinogi, but the three small ones are quite good, might get out some jnats and give them a proper polish/touch up again this eve...

 

[wibbleandstrop23]

In the 80’s, 90’s I worked at a slaughterhouse. We used Victorinox Swiss blades, slaughtering steels and carbon stones moistened with your own, or residual spit. Most of the lads got by with a mediocre knife edge that would get them through the day. In my 15 years there I met maybe 4 or 5 true artists when it came to sharpening. I count myself as on of those.

1 love your knife. It should be as important to you as a ball is to Maradona.
2 Always sharpen on the stone at the same angle as the steel.
3 Use soft feminine strokes on both stone and steel, never rough it up.
4 Use Emery paper and spit on your steel until it’s totally smooth
5 Don’t lend your knife to anyone else, if they aren’t used to a really sharp edge the results can be disastrous.
These five steps helped me keep a razors edge on my blade at all times. With a new knife every 6/8 months.

 

[Legion]

In the 80’s, 90’s I worked at a slaughterhouse. We used Victorinox Swiss blades, slaughtering steels and carbon stones moistened with your own, or residual spit. Most of the lads got by with a mediocre knife edge that would get them through the day. In my 15 years there I met maybe 4 or 5 true artists when it came to sharpening. I count myself as on of those.

1 love your knife. It should be as important to you as a ball is to Maradona.
2 Always sharpen on the stone at the same angle as the steel.
3 Use soft feminine strokes on both stone and steel, never rough it up.
4 Use Emery paper and spit on your steel until it’s totally smooth
5 Don’t lend your knife to anyone else, if they aren’t used to a really sharp edge the results can be disastrous.
These five steps helped me keep a razors edge on my blade at all times. With a new knife every 6/8 months.

+1 No. 5. I worked in a place where nobody had a good knife, and they all needed one, so they borrowed mine.

One guy gave my knife a nice "patina" by dressing roos all night, and then giving it back to me covered in dried blood.

The next guy butchered a goat on concrete, and chipped the blade.

Non knife people can buy their stuff from a Walmart.

 

[wibbleandstrop23]

+1 No. 5. I worked in a place where nobody had a good knife, and they all needed one, so they borrowed mine.

One guy gave my knife a nice "patina" by dressing roos all night, and then giving it back to me covered in dried blood.

The next guy butchered a goat on concrete, and chipped the blade.

Non knife people can buy their stuff from a Walmart.

I loaned my knife out until a guy put it through his forearm, never again after that.

 

[Legion]

I loaned my knife out until a guy put it through his forearm, never again after that.

At least that probably didn't damage the knife.

 

[wibbleandstrop23]

At least that probably didn't damage the knife.

After all these years I still feel terrible about lending it to him.

 

[Legion]

After all these years I still feel terrible about lending it to him.

Don't beat yourself up. Some people can't have nice things.

I knew a guy who threw a party in his new house. A clown did a swan dive off the spring board without noticing the pool was not filled. Not really the pool owners fault, IMO.

 

[Tirvine]

What @cotedupy says about using a coarse stone for blunt or western knives is spot on. The Wusthof tri-stone comes with 240, 1000, and 3000 grit, and the 240 does quick and ruthless work on an edge, getting it into a workable configuration. I only used it once on my old Sabs. It was all they needed. Now I soak everything about 15 minutes and use only the 1000 and the 3000. The edge is fantastic. There is a point at which a knife is ideal in the kitchen in my opinion. It has an extremely fine and polished edge but still just a hint of burr. It will shave your arm or cut paper, but more importantly it will cut a very ripe tomato into slices so thin you could read through them. Most of my friends have knives that cost a lot more than mine, mostly Shuns, Globals, and Wusthofs. None of them cut like my cheap Tojiro ITK 240 gyuto. Regular use of the water stones is a marvelous thing. My son in law has regular sized Naniwas, and they are easy to use the conventional way. They do an amazing job, too. As my stones begin to dish I am starting to decide what to get. I like the 1000 and 3000 regimen, but a finer stone would be tempting if I get three. I can hang onto the Wusthof just for its barely used coarse side should such a need arise.

 

[cotedupy]

I loaned my knife out until a guy put it through his forearm, never again after that.

Probably trying to impersonate Maradona's approach to a football I imagine...

 

[LMcC]

Most of my knives I stop at 800 (Spyderco medium benchstone) and strop. However, a few months ago a decided to make a diamond pasted paddle strop, 1 micron, and with just a couple laps a week on that, I have not needed to touch a stone to any of my knives. Maybe one day, but it’s been working really well.

 

[cotedupy]

What @cotedupy says about using a coarse stone for blunt or western knives is spot on. The Wusthof tri-stone comes with 240, 1000, and 3000 grit, and the 240 does quick and ruthless work on an edge, getting it into a workable configuration. I only used it once on my old Sabs. It was all they needed. Now I soak everything about 15 minutes and use only the 1000 and the 3000. The edge is fantastic. There is a point at which a knife is ideal in the kitchen in my opinion. It has an extremely fine and polished edge but still just a hint of burr. It will shave your arm or cut paper, but more importantly it will cut a very ripe tomato into slices so thin you could read through them. Most of my friends have knives that cost a lot more than mine, mostly Shuns, Globals, and Wusthofs. None of them cut like my cheap Tojiro ITK 240 gyuto. Regular use of the water stones is a marvelous thing. My son in law has regular sized Naniwas, and they are easy to use the conventional way. They do an amazing job, too. As my stones begin to dish I am starting to decide what to get. I like the 1000 and 3000 regimen, but a finer stone would be tempting if I get three. I can hang onto the Wusthof just for its barely used coarse side should such a need arise.

Only thing I'd say is, for the 3k - you (and everybody else) owe it to yourself to get an Ouka / Cerax 3k. It's completely perfect! A Paean to the Cerax / Ouka 3k - https://www.kitchenknifeforums.com/threads/a-paean-to-the-cerax-ouka-3k.54440/

 

[ChefJohnBoy-ardee]

What @cotedupy says about using a coarse stone for blunt or western knives is spot on. The Wusthof tri-stone comes with 240, 1000, and 3000 grit, and the 240 does quick and ruthless work on an edge, getting it into a workable configuration. I only used it once on my old Sabs. It was all they needed. Now I soak everything about 15 minutes and use only the 1000 and the 3000. The edge is fantastic. There is a point at which a knife is ideal in the kitchen in my opinion. It has an extremely fine and polished edge but still just a hint of burr. It will shave your arm or cut paper, but more importantly it will cut a very ripe tomato into slices so thin you could read through them. Most of my friends have knives that cost a lot more than mine, mostly Shuns, Globals, and Wusthofs. None of them cut like my cheap Tojiro ITK 240 gyuto. Regular use of the water stones is a marvelous thing. My son in law has regular sized Naniwas, and they are easy to use the conventional way. They do an amazing job, too. As my stones begin to dish I am starting to decide what to get. I like the 1000 and 3000 regimen, but a finer stone would be tempting if I get three. I can hang onto the Wusthof just for its barely used coarse side should such a need arise.

In regards to your dishing stones, you can flatten them. You don't need a multi-hundred dollar flattening stone either. I use my atoma 90 but before I had that I would take a piece of dry wall mud sanding screen on a flat table and run the stone over that keeping it all very wet. Some internet searches may show ways that would work better for you.

I know Murray Carter will use the higher edges to sharpen small blades to try and even them up. It is all up to you. New stones are fun too.

My Naniwa 400 is getting thin and I'm expecting it to crack sometime in the future. I'll probably get another.

Golly, knowing how thick that bugger was when I got it 8 years ago means I've sharpened some knives since then! Jeepers.

 

[cotedupy]

Yesterday I did a full razor honing progression for the first time, and it highlighted another notable difference between sharpening a razor and a knife. I said above that 'de-burring' was a very important aspect of sharpening a knife, but for much of razor honing you are not trying to raise a burr. So here's something about that...

A burr (as I'm sure everyone knows) is a bit of steel that has been kinda folded over to one side during the sharpening process. Once you've raised a burr all the way along the edge you flip the knife over and sharpen on the other side. When you've raised a burr on that side you know that your edge apex meets, and then you get rid of the burr by sharpening at a lighter pressure or higher grit, or possibly higher angle. That's basically how you sharpen a knife.

[The pictures and video below are highly exaggerated examples that I did to make a point - you *don't* want to raise such a large visible burr.]

This shiny, ragged-looking bit along the edge is a massive burr:

Here's what it looks like from the end or 'choil' - the bit bent round to the right. Notice that the angle of the main bevel is more acute than the sharpening angle. This is a major difference between most freehand knife sharpening and razors.

At the moment that knife above is going to be very blunt to use. It's not going to slice cleanly through anything because it still has the burr on it. And as soon as it hits a board it'll fold over further / get smashed into the edge / just be a bit of a mess.

So you need to get rid of it. This video (of the same knife, about a minute after I took those pics) shows the importance of deburring. At the beginning it won't cut paper at all. Then I do something that in theory should make the knife blunter - sawing through a cardboard tube - but actually turns out to make it sharper, by tearing the burr off the edge.

As I say - this is just a silly exaggerated example that I did for a bit of explanatory fun. I do not necessarily recommend the kitchen-roll-tube-deburring-method for your everyday sharpening setup. You want to be doing it on a stone!

 

[cotedupy]

Here's a little explanation of why you don't want a kitchen knife as sharp as can possibly be, and why higher grits aren't necessarily better. Copied from my post on KKF regarding cutting tomatoes:

---

I did a couple of slightly exaggerated drawings to help anyone new understand this phenomenon...

If you cut down on a tomato at 90 degrees and perfectly straight; you will cut through it, no matter how overly refined your edge is. Like this:

But the majority of the time you're not neatly bisecting a tomato; you're cutting it at an angle, because a tomato is round. And to compound matters you might be using a push or pull cut, rather than chopping straight down. It looks more like this:

Where 'b' is the angle of your edge (sharpening angle). 'a' is 90 degrees minus 'b'. And 'c' is 90 degrees minus the angle you're cutting the tomato at. As soon as 'c' starts getting close to the same as 'a' - that's when you run into problems. And if 'c' is larger than 'a' - you’re really going to struggle if your edge is super slick.

Pretty much all cutting of stuff is the result of friction. If you don't have friction you can't cut anything. A tomato skin is fairly smooth, and if you combine that with a very refined edge you have quite a low coefficient of friction between the two. But that isn't the real kicker here... the really important thing is the 'normal force' exerted by the tomato upwards against your knife.

The normal force is obviously considerably reduced when you're cutting the curved surface of a tomato at an acute angle. And it's also reduced because the pulp is soft. The reason tomatoes are brought up again and again in this test isn't necessarily because the skin is unreasonably tough - the skin of a capsicum or bell pepper is probably tougher, and equally smooth. It's the combination of soft flesh, with skin that is both tough-ish, and smooth, that all together kill the friction generated when cutting it. Try cutting a wet tomato vs a dry one and you'll see the importance of friction.

But unfortunately, apart from making sure it's dry, you can't really change your tomato, so you have to change your knife. You could do this by lowering your sharpening angle, but that might make it less durable, and annoying to maintain. So you do it by finishing the edge at a lower grit, with more teeth, and a higher coefficient of friction...

And now at last you can truly hope to achieve the bruschetta of your dreams, and know the panzanella in the mind of god!


[I think I've got most of that physics right anyway, and hopefully explained in a semi-understandable way.]

 

[Doc4]

Where 'b' is the angle of your edge (sharpening angle). 'a' is 90 degrees minus 'b'. And 'c' is 90 degrees minus the angle you're cutting the tomato at. As soon as 'c' starts getting close to the same as 'a' - that's when you run into problems. And if 'c' is larger than 'a' - you’re really going to struggle if your edge is super slick.

So ... one is not so much 'cutting' the tomato as rubbing the side of the knife against the side of the tomato.

so you have to change your knife. You could do this by lowering your sharpening angle, but that might make it less durable, and annoying to maintain. So you do it by finishing the edge at a lower grit, with more teeth, and a higher coefficient of friction...

You will get a kick out of this.

I have a small (8"?) Henckels chef knife. 4-star IIRC. Had it for years ... great knife, if somewhat pedestrian. At some point in the last few years, either SWMBO or the lady who babysat our son before he started going to school put a "ding" in the blade. Nasty little notch about halfway down the blade. Semi-cricular notch about 1.5mm around. Not huge, but annoying as all heck.

Gosh darn it, can't people take care of my knives??

*sigh*

Well ... silver lining to that dark cloud ... the knife is now fantastic as slicing tomatoes.

 

[Ron R]

I got interested in wet shaving years ago looking for a knife sharpening system on youtube and found this Lansky system(offshore clone?). I'm not a professional knife sharpener but I can tell you this system works well and the way we use or degrade knifes around our kitchen, it is just what I needed. If a person has fancy knifes you should tape the sides of the blade to prevent scratching & especially with the diamond rods it comes with. When done sharpening I can slice receipt paper from the grocery store like scissors will cut paper.
I found that starting with a 15 degree or 30 degree included angle and then finish with the 20 degree or 40 degree included angle is the best edge for a kitchen knife for our household. It is basically a surgeons scalpel edge which is the strongest edge for slicing.
....Start out with 30'included angle......................2nd angle 40'included angle....................large knife ceramic steel

I was disappointed with Lansky angles they drilled and had to improve them.......edge results 3 facet grind is perfect. 400X mag

I drilled better holes on the back side of the Lansky kit I bought off of _bay(clone?), I made a template to correct the angle inaccuracies. The Lansky is portable for hunters who have to skin outdoors also.

 

[hairless wonder]

I got interested in wet shaving years ago looking for a knife sharpening system on youtube and found this Lansky system. I'm not a professional knife sharpener but I can tell you this system works well and the way we use or degrade knifes around our kitchen, it is just what I needed. If a person has fancy knifes you should tape the sides of the blade to prevent scratching & especially with the diamond rods it comes with. When done sharpening I can slice receipt paper from the grocery store like scissors will cut paper.
I found that starting with a 15 degree or 30 degree included angle and then finish with the 20 degree or 40 degree included angle is the best edge for a kitchen knife for our household. It is basically a surgeons scalpel edge which is the strongest edge for slicing.
....Start out with 30'included angle......................2nd angle 40'included angle....................large knife ceramic steel
View attachment 1340006 View attachment 1340007 View attachment 1340008
I was disappointed with Lansky angles they drilled and had to improve them....................edge results 3 facet grind is perfect.
View attachment 1340005 View attachment 1340016
I drilled better holes on the back side of the Lansky kit I bought off of _bay, I made a template to correct the angle inaccuracies. The Lansky is portable for hunters who have to skin outdoors also.

I bought a similar sharpening system, the Spyderco Sharpmaker. I use it to sharpen my kitchen knives and my pocketknives.

 

[Ron R]

I bought a similar sharpening system, the Spyderco Sharpmaker. I use it to sharpen my kitchen knives and my pocketknives.

Spyderco makes a excellent sharpening kit!

 

[Tirvine]

Here's a little explanation of why you don't want a kitchen knife as sharp as can possibly be, and why higher grits aren't necessarily better. Copied from my post on KKF regarding cutting tomatoes:

---

I did a couple of slightly exaggerated drawings to help anyone new understand this phenomenon...

If you cut down on a tomato at 90 degrees and perfectly straight; you will cut through it, no matter how overly refined your edge is. Like this:

But the majority of the time you're not neatly bisecting a tomato; you're cutting it at an angle, because a tomato is round. And to compound matters you might be using a push or pull cut, rather than chopping straight down. It looks more like this:

Where 'b' is the angle of your edge (sharpening angle). 'a' is 90 degrees minus 'b'. And 'c' is 90 degrees minus the angle you're cutting the tomato at. As soon as 'c' starts getting close to the same as 'a' - that's when you run into problems. And if 'c' is larger than 'a' - you’re really going to struggle if your edge is super slick.

Pretty much all cutting of stuff is the result of friction. If you don't have friction you can't cut anything. A tomato skin is fairly smooth, and if you combine that with a very refined edge you have quite a low coefficient of friction between the two. But that isn't the real kicker here... the really important thing is the 'normal force' exerted by the tomato upwards against your knife.

The normal force is obviously considerably reduced when you're cutting the curved surface of a tomato at an acute angle. And it's also reduced because the pulp is soft. The reason tomatoes are brought up again and again in this test isn't necessarily because the skin is unreasonably tough - the skin of a capsicum or bell pepper is probably tougher, and equally smooth. It's the combination of soft flesh, with skin that is both tough-ish, and smooth, that all together kill the friction generated when cutting it. Try cutting a wet tomato vs a dry one and you'll see the importance of friction.

But unfortunately, apart from making sure it's dry, you can't really change your tomato, so you have to change your knife. You could do this by lowering your sharpening angle, but that might make it less durable, and annoying to maintain. So you do it by finishing the edge at a lower grit, with more teeth, and a higher coefficient of friction...

And now at last you can truly hope to achieve the bruschetta of your dreams, and know the panzanella in the mind of god!


[I think I've got most of that physics right anyway, and hopefully explained in a semi-understandable way.]

Reminds me of the story of the Michelin starred chef in a kitchen to demonstrate a technique. He says the knives are too sharp to do good work!