Knife sharpening

[novicewetshaver]

hello again cadre, do we have anyone here who is experienced with sharpening japanese chef's knives? i was wondering if i could pick your brain about knife sharpening and different stones and how best to go from one stone to another.

 

[Spider]

@ShawnF

 

[novicewetshaver]

thx!

 

[ShawnF]

Who? Me? What makes you think I know how to sharpen a knife???

I don't have any actual Japanese knives novicewetshaver, but I have sharpened a couple knives.
I'm no expert but I'll help if I can. What are you having issues with?

 

[novicewetshaver]

Who? Me? What makes you think I know how to sharpen a knife???

I don't have any actual Japanese knives novicewetshaver, but I have sharpened a couple knives.
I'm no expert but I'll help if I can. What are you having issues with?

so i understand that when you get your knife to the 1000 grit stone you are looking for a bur to develop on one side of the knife then you switch over to the other side of the knife and then you get a bur on that side and the knife and then your pretty much done with the 1000 stone. from what ive read/watched about sharpening german style chefs knife at this point you would be done because theres no further value in taking it to 6k and beyond. For a japanese chef knife, depending on what you are cutting, you would want to sharpen them on higher grits stones. i have a kingston 1000/6000 whetstone, how would i know when the sharpening is done on the 6k stone if your not really looking for a bur to develop its more of polishing the blade at that point. any thoughts would be helpful. thanks

 

[ShawnF]

Both knives would depend on the steel and the hardness left in them after heat treat. Generally, German and other "western" style knives are around 55ish on the rockwell hardness scale. Some of the Japanese knives are generally closer to 60 HRC. (A metal file is generally 62HRC for reference.)
That is not to say they all are that way, but western style are usually a more general purpose knife and left a little softer so the chance of edge chipping is lower when chopping. Japanese knives are typically more specific in their intended use, so left harder to take a keener edge.

As far as the grit stone you are going to need, intended use plays into how high you want to go. If you are staying just general purpose, you can put a very serviceable edge on with the 1K that will last you a good while. My two I use in the kitchen the most came out of heat treat right about 61-62HRC after tempering, but I keep a 2K edge on them and it will last me a year before needing to touch them up.

As to your direct question though, you still need to make sure the burr is gone and get it just as smooth as you can on the 1K if you are jumping straight to a 6. Especially on a harder blade or you will be there for ages trying to refine it with that large of a jump. If it is possible for you, I would say get a 2 or 3K stone. The Kuromaku are my preferred stones at lower grits. They are a Japanese branded Shapton Pro ceramic waterstone that can usually be had for about half the price of the American branded stone. There are other decent options out there as well.
The mid grit would get you a very keen edge for pretty much anything. It would also lessen the effort needed to do the 6K work if you choose to go that high.

For the grits above 1K, you are pretty much doing as you said and just polishing. So you are looking to remove the scratch pattern left by the previous grit stone. They don't really stick like a razor would, but if you have a light enough feel it will seem a bit smoother as you get the full polish.

 

[novicewetshaver]

alrighty for my next sharpening i will try that out. normally on when im on the 1k stone i do try to knock the burr off. after i get a burr on both sides i will do a 10, 8,6,4,2 strop to get rid of the bur. right know i only have the kingston waterstone 1k/6k and some kind of purple stone i got off another member from a different site and a naniwa 220 stone. my knife is an 8 in shun hero sg-2 that i use for daily cooking.

 

[novicewetshaver]

Both knives would depend on the steel and the hardness left in them after heat treat. Generally, German and other "western" style knives are around 55ish on the rockwell hardness scale. Some of the Japanese knives are generally closer to 60 HRC. (A metal file is generally 62HRC for reference.)
That is not to say they all are that way, but western style are usually a more general purpose knife and left a little softer so the chance of edge chipping is lower when chopping. Japanese knives are typically more specific in their intended use, so left harder to take a keener edge.

As far as the grit stone you are going to need, intended use plays into how high you want to go. If you are staying just general purpose, you can put a very serviceable edge on with the 1K that will last you a good while. My two I use in the kitchen the most came out of heat treat right about 61-62HRC after tempering, but I keep a 2K edge on them and it will last me a year before needing to touch them up.

As to your direct question though, you still need to make sure the burr is gone and get it just as smooth as you can on the 1K if you are jumping straight to a 6. Especially on a harder blade or you will be there for ages trying to refine it with that large of a jump. If it is possible for you, I would say get a 2 or 3K stone. The Kuromaku are my preferred stones at lower grits. They are a Japanese branded Shapton Pro ceramic waterstone that can usually be had for about half the price of the American branded stone. There are other decent options out there as well.
The mid grit would get you a very keen edge for pretty much anything. It would also lessen the effort needed to do the 6K work if you choose to go that high.

For the grits above 1K, you are pretty much doing as you said and just polishing. So you are looking to remove the scratch pattern left by the previous grit stone. They don't really stick like a razor would, but if you have a light enough feel it will seem a bit smoother as you get the full polish.

i have been thinking about getting some more whetstones as well, should i get anything under 1k? also should i go for a 2k or 3k stone? which would be better before moving onto the 6k? what would you recommend for going above 6k? i do a lot of vegatable chopping, onions carrots potatoes tomatoes, so for me the sharper the knife the better. thanks again.

 

[ShawnF]

Sorry, thought I had wrote back....

3k would be a happy medium. Depending on what you get will determine the time spent on it. I know I sound like a salesman for the kuomaku, but they are a fast cutting long lasting splash and go.
Not that there aren't other stones that will get you the same results, these just seem to be so much less hassle. I had Norton, have a king, had naniwa, had slates.... the shapton are just my personal favorites for spending the least time with the mast result.

As far as a higher grit, I would say get a 3k and try that edge. Then move to the 6k and try that before worrying about going higher. I have a couple short cutting vids somewhere in my forging thread. You can see the blade through an onion slice in one and that was the 2k edge. I can drag cut through a pork loin, drag cut through onions with the skin on... you'll be surprised at what you can do with a 2 or 3k edge.

 

[novicewetshaver]

Sorry, thought I had wrote back....

3k would be a happy medium. Depending on what you get will determine the time spent on it. I know I sound like a salesman for the kuomaku, but they are a fast cutting long lasting splash and go.
Not that there aren't other stones that will get you the same results, these just seem to be so much less hassle. I had Norton, have a king, had naniwa, had slates.... the shapton are just my personal favorites for spending the least time with the mast result.

As far as a higher grit, I would say get a 3k and try that edge. Then move to the 6k and try that before worrying about going higher. I have a couple short cutting vids somewhere in my forging thread. You can see the blade through an onion slice in one and that was the 2k edge. I can drag cut through a pork loin, drag cut through onions with the skin on... you'll be surprised at what you can do with a 2 or 3k edge.

ok, i think i invets in a 3k stone for know. have you used the suiero cerax stones at all? if so how do the perform against teh kumaku. Aslo is there a stone fixer i could use for a natural stone? the guy i got it off said it was about a 12k stone. i accidently gouged it while i was doing a sharpening session. is there a stone fixer i could use on my 6k as well, i need to rechamfer the sides on it as well. thanks again.

 

[ShawnF]

Haven't used the cerax stones but the reviews look good. I don't think they would be a bad choice.
For flattening there are diamond plates ou there but they can be pretty expensive. Cheaper alternative is a flat surface and some wet/dry sandpaper. That's all I use to dress my stones. Works on my asagis, ceramics, king, and cotis. Used it on my Chinese slate I used to have also, which sounds like what your purple one may be. They were usually blue or purple and claimed to be in the 10/12k range.
Sometimes for doing chamfers easier, I will just use a mill bastard file. Not too toothy, but will cut a nice chamfer. You can do it with the wet/dry but I have them lying around.

 

[novicewetshaver]

ok, i have 220 wet dry sand paper, would that be ok to use on the 6k and the purple natural stone? i took my japanese knife to a place down here called chef's toys to get it sharpened. i'm not sure what progession they used but when i got the knife back it didnt feel sharp at all, i couldnt really feel the teeth of the blade, there were a lot of grind marks on the blade itslef and some kind of wierd black powder/residue and there was no polish on the blade whatsoever. also the edge starting chipping away after a few weeks of use, it was big chipping but more like a lot of smaller ones along the edge of the blade. it was all along the blade edge. im not sure they sharpened it correctly. what would be the proper progression of stones to use if i wanted to get a really sharp edge? should i go below 1k and work my way back up? thanks again

 

[novicewetshaver]

here is a picture of the purple stone, not really sure what grit it is, they are suppose to be somewhere around 12k. paid 100 bux for them off of a member from a diff forum.

 

[ShawnF]

220 will work just fine. Keep it wet as you are doing it and you will need to rinse the wet/dry off as the slurry builds on it. So doing it by/in the sink is good. You should wear down your paper as you are doing the bull work letting you get a better finish on your stone once it is flattened out. If it still looks a little scratchy, just up the grit on the paper a little to like a 320 or 400. The little surface scratches won't be as critical for knives as it is with straight razors, but still nice to get them out if you can.

I am going to bet that the progression they used is a slow speed wet grinder followed by the leather stropping wheel on the other side to knock the burr off. That would explain the deep grind marks and the (probably) buffing compound residue. Most of those places don't know how to sharpen on stones. It's easier to teach the minimum wage help how to set a guide and grind than to actually use stones. That, and the time involved for both training and sharpening doesn't seem worth it for them.

I am not sure what that stone is. It looks like a slate, but the odd coloring is throwing me off.

I see you are in the US. If you want, you can send it to me and I will put an edge on it for you so you have a starting point. I can do my normal 2k edge and you can see how you like it, then you will have a better base if you want to move up past that.

If you want to do it yourself, I would say take it to your 220 naniwa and get rid of any of the chipping, get the bevel refined, and get rid of that burr. Then go to your 1k. The naniwas I had were pretty smooth, (superstones) so it shouldn't be an extreme amount of work to get that scratch pattern removed on the 1k.

Don't laugh at my pathetic cutting skills, but here is one I sharpened with my normal progression.

 

[novicewetshaver]

thats probly what happened, i wont take it there again. i shaprened my knife on monday and it felt pretty sharp, but then i used to cut a bunch of veggies and when i was done it felt like it had no edge again. i resharpened it today and it will cut through paper. i stropped it after i did my sharpening progression. not sure what happened. im still tryin to get this sharpening thing down

 

[ShawnF]

May not have gotten the burr completely removed and that was what you were feeling as your edge, or could be the bevel angle got changed when they ground it. Hopefully they used a wet grinder and didn't take the temper out of it. That knife boasts a 64hrc so the edge should last forever.

The offer is there if you want me to check the bevel and get you going. It is easier to learn from maintaining a good edge than to try and learn from correcting a bad one.

 

[novicewetshaver]

May not have gotten the burr completely removed and that was what you were feeling as your edge, or could be the bevel angle got changed when they ground it. Hopefully they used a wet grinder and didn't take the temper out of it. That knife boasts a 64hrc so the edge should last forever.

The offer is there if you want me to check the bevel and get you going. It is easier to learn from maintaining a good edge than to try and learn from correcting a bad one.

sounds good, i may just do that. i resharpened the knife yesterday and was able to cut through paper again, going to see how it cuts today. is there any way to check if the temper of the blade has changed? also when i bought my waterstones the lady at the store told me i could go from 220 and then go to 1k to do the sharpening, is this true? do the grits from 220 to 1000 not matter for sharpening?

 

[novicewetshaver]

Also im thinking about getting either a 2k or 3k kuromaku but not sure if i should get the 2k or 3k? any thoughts on this?

 

[ShawnF]

As far as the temper, discoloration is the first clue. However if they did grind then buff it, the buffing can take the discoloring off. Beyond that, you need some sort of hardness tester. I have a set of hardness files that will let you know within a 5 hrc range. If you do end up sending it off this way, we can make sure it's still between 60 and 65 at least.

Technically, you can go from a broken piece of concrete to a hard ark. It just depends on how much work you want to put into it. Also, intended use plays into how fine of an edge you want. You hone a low angle and 12k finish it will slice like no tomorrow, but you take it out and chop a piece of kindling wood for your campfire and you will destroy it. Same in reverse, You put a nice 6 or 8 hundred grit apple-seed edge on and it will chop all day, but it will never give you a paper thin slice of anything. So there is a use for the lower grit stones, it just depends on how much time (and money) you want to spend on each stone and what you want your end result to be.
For a basic setup, a 220 or 400ish to 1k will work just fine. Realistically with proper maintenance on a good edge, you won't ever need to go to the 220 unless you do something that chips the edge and you need to do some serious hogging to get it out.

For your setup, I would say the 3k would fit in nicely. I have the 2k for setting bevels on straight razors. (then a 5 and 8 before getting to my naturals) They are very fast cutters, so I can do the work that normally needs a 1k but leave a smaller scratch pattern to remove. I just flip it to the back side if I need to touch up a kitchen knife.
The 3k for you would still be aggressive enough that you shouldn't need to put in a crazy amount of time to get the 1k scratches out, but be fine enough to make the jump to 6k more pleasant also.

 

[novicewetshaver]

As far as the temper, discoloration is the first clue. However if they did grind then buff it, the buffing can take the discoloring off. Beyond that, you need some sort of hardness tester. I have a set of hardness files that will let you know within a 5 hrc range. If you do end up sending it off this way, we can make sure it's still between 60 and 65 at least.

Technically, you can go from a broken piece of concrete to a hard ark. It just depends on how much work you want to put into it. Also, intended use plays into how fine of an edge you want. You hone a low angle and 12k finish it will slice like no tomorrow, but you take it out and chop a piece of kindling wood for your campfire and you will destroy it. Same in reverse, You put a nice 6 or 8 hundred grit apple-seed edge on and it will chop all day, but it will never give you a paper thin slice of anything. So there is a use for the lower grit stones, it just depends on how much time (and money) you want to spend on each stone and what you want your end result to be.
For a basic setup, a 220 or 400ish to 1k will work just fine. Realistically with proper maintenance on a good edge, you won't ever need to go to the 220 unless you do something that chips the edge and you need to do some serious hogging to get it out.

For your setup, I would say the 3k would fit in nicely. I have the 2k for setting bevels on straight razors. (then a 5 and 8 before getting to my naturals) They are very fast cutters, so I can do the work that normally needs a 1k but leave a smaller scratch pattern to remove. I just flip it to the back side if I need to touch up a kitchen knife.
The 3k for you would still be aggressive enough that you shouldn't need to put in a crazy amount of time to get the 1k scratches out, but be fine enough to make the jump to 6k more pleasant also.

ok, i will look into getting a 3k sharpening stone of some sort. someone on another forum has a coticule up for 115 bux, would this be a good buy and could i use it to sharpen/polish my knife as well and if so where would it fit into the sharpenin/polishing rotation?