The Knife Thread

We've had a set of Whustof gourmet knives, which are their budget oriented set, for about 4 years. Very lightweight, very sharp. I really like them, but eventually I want to move up to their higher quality stuff.

 

Really depends on the steel, I have up to 6000 and some steels can see the added benefit and some don't be it for reasons of hardness or grain size. I find steels with high vanadium content don't take to high grits all that well.

 

For "all family use" kitchen knives I have Chef's Choice electric sharpeners. Model 120 for softer steels and 15XV for harder. They are bringing knives to shaving sharpness what is good enough for my family use. Manual sharpening is reserved for special knives. Otherwise it would take too much time.
I bought model 120, I think, about 20 years ago, as soon as number of kitchen knives went close to ten.

 

So I'm reading that a lot of the grits are not the same between manufacturers, though they're in the same ballpark-ish.
I found this:
https://docs.google.com/spreadsheets/d/1VaTf3MXuwuvH-QLwOci4f9B9Zhkbuu1wjoSCZIUsR-o/edit#gid=0

So my new Miyabi is an SG2 steel with a hardness of 63 which I understand is way up there. It'll probably be a while before I even need to sharpen it, but I suspect my wusthof stone would not be up to the task and I'd need some kind of ceramic/glass to do it?

 

Powder metals are kind of nuts. I once saw a machinist work on a powder metal gear with something in the grade of TiCarbide, later with some kind of nitride coating on the cutting tool. The gear won. Mind you, Ti carbide coatings are already 9.5 of diamond hardness. I did the research when I was getting a carbide tool for my machine.

You might need to go to a specialist forum with this question.

 

Me too. I think mine's a 120. I have all carbon-steel knives, relatively easy to sharpen, but need it more often. The Chef's choice is a really great no-skill knife sharpener. I have a drawer full of crap that was supposed to sharpen knives!

The micro-serated edge it produces is not so aesthetically pleasing, but it certainly cuts.

When I want to be fussy, I strop. I use a polishing compound. I also use the strop (leather on wood) for polishing the sides of a knife, which is probably never needed for stainless, but carbon-steel gets all sorts of cruddy.

Grit grades? Be practical! How sharp do we need? Anyone here removing skin for transplant? Or slicing materials for the microscope? I've heard that there are specialist blades in those kind of areas that are simply impossible to touch without cutting oneself!

I do resharpen disposable scalpel blades, but I'm no surgeon, don't need them for anything more than miscellaneous craft work, and find the brand difficult to source where I am. I'd say, though, that I get a fairly decent edge compared to new. I use sandpaper (emery) glued to a stick. I do have some very, very fine stuff: for a jeweller, it's closer to polishing than sanding (although sanding is still the technical term).

Various grades of emery stuck to various shapes of stick makes for very useful tools. A trick learnt from the jewellery trade.

 

I'm applying the same level of neurosis on audio gear to knife sharpening here

Yes I'm perfectly fine with a 2000 grit stone for kitchen work and can slice through paper easily enough, but dammit I want to be able to drop a handkerchief woven by endangered Tibetan silkworms onto my knife delicately balanced on one finger and have it slide so silently through that I'll need to justify buying a 4k gopro just to film it.

 

Oh come now, that's absurd! You need one of those super-slow-motion cameras, thousands of frames a second.

Although you could use the gopro for the bts sequences.

I say... Go for it!

 

A Shapton, Naniwa or equivalent water stone would be my pick. I use a Shapton Glass on VG10 (softer than SG2) and HAP40 (harder than SG2). Works well, which it should given it is designed for these types of steels.

You will need something to maintain the edge with day to day use. No steel can go for months of use without any attention. I already mentioned what I use upthread, but there are a lot of differing opinions and preferences when it comes to edge maintenance.

For detailed background knowledge on sharpening, I recommend checking out scienceofsharp.com. Not a great place for learning how to sharpen, but it dispels a lot of misinformation you are likely to run into while doing research.

 

Oh wow, speaking as a guy with a background in metallurgy and microanalysis, this site ticks so many of my boxes...

 

I have tool blades in M2 and Aogami Blue #2, which are both roughly the same hardness as SG2 (61-64). I have been able to sharpen them with both a Suehiro Cerax 1010 (1000 grit ceramic) and an Atoma 1200 (1200 grit diamond plate). I like the feel of the ceramic better than the diamond plate, but the diamond works a little faster. I semi-polish on a Suehiro Rika 5000 (ceramic) and it feels amazing and gives a satiny finish. A little stropping on some horsehide with some diamond paste and I can get them to pop hairs. I would like to try the Naniwa Chosera stones since they are splash and go, but I have sunk almost more into stones and strops than I have knives, so I kind of need to stop...

 

Grit classifications are also country-specific. I have a chart that maps them between each other somewhere. Some of them are pretty close; others are not.

 

Pretty sure I have more sunk into my amps/dacs than I do my headphones by nearly an order of magnitude...

 

Just do not forget why you are sharpening your knives
For example, a knife for boning, especially fish, easily can be too sharp for comfortable work, - you want these knives cut meat but glide along bones, not cut in them.

 

I have SG2 (from Miyabi) steel as well and these are actually in the camp where I don't bother going above 3k. They only stay razor sharp for like a few cuts and then reverts to working sharp (granted for a REALLY long time). I don't know what it is about the grain structure or slightly higher Vanadium content, but SG2 really doesn't like to hold razor sharp.

 

What stones do you use on your SG2?
Do you ever hone or strop them between sharpenings?
I know I'm just fussing over details, but new hobby syndrome and all that.

 

One or two swipes. each side, on a steel restores the edge, and makes for much longer gaps between actual sharpening.

 

While honing and stropping are not quite the same thing, using one and/or the other, depending on blade usage and material, greatly extends the cutting ability of an edge before actual sharpening is required. I hone or strop my blades typically with every use. Actually needing to sharpen them is pretty infrequent.

 

I'd have to look up my stones, I currently use some combo stone that I'd probably never do again. On that front, make sure you have stone fixer.

I do occasionally hone/strop between sharpenings but it's pretty infrequent mostly because you'll need a ceramic honing rod because SG2 is too hard for most steel rods and quite frankly the steel itself doesn't deform easily. I find myself only craving a strop before cutting something difficult like tomatoes, otherwise it stays functionally sharp for a long time.

 

Over-ripe tomato: to slice thin with barely any downward pressure on the knife.

That's my test. Well, I eat a lot of tomato!