J-Nat Questions

[Chamber]

Good evening fellow KKF jnat maestros. Looking for some honing wisdom. I purchased my first few natural stones this past week and have some questions. First of all, I am familiar with using synthetic stones typically a 1K stone then onto a finisher such as a 3K or even 6K. I am mainly sharpening carbon steel Gyutos. I can get decent results using synthetics. basic method of sharpening to a burr on the 1K, stropping on the stone then moving on to the finisher to remove the scratches and polish everything up.

What I would like to know is what do I need to do differently when finishing on a natural stone? I have an Aoto, Aizu and Shobudani Iromono. Do I need to raise a burr with these stones? Do I use back and forth strokes like I do on the 1K stone or just use X edge leading cross strokes? Do I strop on natural stones? How much water or slurry do I need to raise? So many questions.... For the most part all 3 of my natural stones feel pretty soft to medium fineness and raising slurry isn’t an issue. Just not sure what the standard operating procedure should be when using natural stones.

 

[lemeneid]

You don't do anything different you would do on synths. The big difference is mud and water management. For the stones you have, they don't generate much mud, the Shobu might be a little harder but not by much, and my aim for those would be for thick but well flowing mud. For stropping, I usually wash off the mud and hone on bare stones, its a little trick I learned from the razor people to get the edge sharper than it should get.

The Aizu and Aoto should finish at about the same level with the Shobu a little finer, so see which one you like better.

 

[Marcelo Amaral]

I agree, follow your sharpening technique on naturals and see what you get.
I feel the biggest difference when comparing synths and naturals is that naturals are about finesse.
In my experience, naturals excel on blades that are thin behind the edge and whose steels are hard enough to keep those thin edges.

 

[Marcelo Amaral]

@lemeneid: may i ask you to explain this stropping process you learned from the razor people?

 

[Chamber]

Do I need to raise a burr on the naturals?

 

[lemeneid]

@lemeneid: may i ask you to explain this stropping process you learned from the razor people?

Its nothing unusual. Just keep using lesser mud on your finishing stone. The idea is mud can generate more mud and when there is more mud, there are larger particles. Lesser mud means lesser particles and lesser big particles. When your particles are smaller, the finer the edge gets.

 

[lemeneid]

Do I need to raise a burr on the naturals?

The process at each progression is the same and I would say yes.

 

[Marcelo Amaral]

I usually raise a burr, specially on stones that are not too hard.
Sometimes, by the end of my progression, i don't raise a burr on the last stone(s) as they are used to polish the edge and get rid of the remaining burr.

 

[Marcelo Amaral]

Thanks for the answer, lemeneid, it makes sense.

 

[Chamber]

I usually raise a burr, specially on stones that are not too hard.
Sometimes, by the end of my progression, i don't raise a burr on the last stone(s) as they are used to polish the edge and get rid of the remaining burr.

Yeah I typically don’t get a burr on my 6K synthetic stone. I just use it to polish and refine the edge then strop. With the naturals a burr is attainable but just wasn’t sure If I should work to get to that point or just lightly refine the edge like my synthetic finishers.

 

[Marcelo Amaral]

I guess it's your choice.
I find it easier to raise a burr on synthetics than on naturals as a rule.

Sometimes the gap between the coarser and the finer stone is too big and it would take forever to raise a burr on the finer stone.
The obvious answer would be to get a middle stone, but, at least in my experience, it works to polish the edge on the finer stone without a middle stone too.

In order to make sure no burr is left, i use Jon Broida's teachings on how to remove a burr on this link.


Also, the three finger sharpness test is useful to feel if there's some burr left.

 

[lemeneid]

Yeah I typically don’t get a burr on my 6K synthetic stone. I just use it to polish and refine the edge then strop. With the naturals a burr is attainable but just wasn’t sure If I should work to get to that point or just lightly refine the edge like my synthetic finishers.

I guess it's your choice.
I find it easier to raise a burr on synthetics than on naturals as a rule.

Sometimes the gap between the coarser and the finer stone is too big and it would take forever to raise a burr on the finer stone.
The obvious answer would be to get a middle stone, but, at least in my experience, it works to polish the edge on the finer stone without a middle stone too.

In order to make sure no burr is left, i use Jon Broida's teachings on how to remove a burr on this link.


Also, the three finger sharpness test is useful to feel if there's some burr left.

It really depends, raising a burr is easy IF your knife's edge is thin enough. Which is why I always take the approach of continuous thinning, so the edge never gets fat. I definitely get a burr more easily on jnats, even on my finest stone, which is about 20k grit equivalent, i feel it after 3-4 passes. Thats how thin my knives are at the edge and thats how you get the best cuts. Once my knives have gone through that one and only major thinning, all I ever use are my fine stones when sharpening. And you waste less metal going forward this way too since all you're sharpening on are fine stones, not coarse ones.

 

[Marcelo Amaral]

I can see your logic of taking your edges to the extreme, but to each his own.

For most of my double bevel edges, i prefer them a bit sturdier (for single bevel blades, that's another story).
For my tastes, a double bevel blade should hold a zero grind and don't microchip even without a microbevel.
This kind of more conservative edge is ideal for me at the kitchen as it falls through hard product, but at the same time is very sturdy.

Just to give an example the kind of conservative edge i'm talking about: yesterday i sharpened a 270mm Ikeda suminagashi blue #1 gyuto for the first time (i got it new from Bernal) using the progression: Numata, Ikarashi, Maruoyama. It took me half an hour, most of the time spent on setting the bevel on the numata.
I felt i could have had an intermediate stone between the ikarashi and the maruo and i didn't raise a burr on the maruo, but the edge was polished enough and the Ikeda sliced and diced the peppers (for a pasta sauce) like butter. The Ikeda edge can definitely be thinned (it's not nearly as thin behind the edge as my Gesshin Ittetsu W#2), but i see no point doing that to the Ikeda if it's already sharp enough for kitchen use and it has now a sturdier edge.

 

[Rotem Shoshani]

I can see your logic of taking your edges to the extreme, but to each his own.

For most of my double bevel edges, i prefer them a bit sturdier (for single bevel blades, that's another story).
For my tastes, a double bevel blade should hold a zero grind and don't microchip even without a microbevel.
This kind of more conservative edge is ideal for me at the kitchen as it falls through hard product, but at the same time is very sturdy.

Just to give an example the kind of conservative edge i'm talking about: yesterday i sharpened a 270mm Ikeda suminagashi blue #1 gyuto for the first time (i got it new from Bernal) using the progression: Numata, Ikarashi, Maruoyama. It took me half an hour, most of the time spent on setting the bevel on the numata.
I felt i could have had an intermediate stone between the ikarashi and the maruo and i didn't raise a burr on the maruo, but the edge was polished enough and the Ikeda sliced and diced the peppers (for a pasta sauce) like butter. The Ikeda edge can definitely be thinned (it's not nearly as thin behind the edge as my Gesshin Ittetsu W#2), but i see no point doing that to the Ikeda if it's already sharp enough for kitchen use and it has now a sturdier edge.

I like your approach, Tanaka VG10 grinds are a perfect example of this school of thought in that they are thin bte but fat enough just to support those last 2-3mm for prolonged use, I'll normally add a micro bevel just to delay the next sharpening session, I might lose the ability to whittle hair, but who cares really, just lasts forever.

 

[Marcelo Amaral]

I can relate to both points of view, although at the end of the day, this more conservative approach ended up being my choice for most of my sharpening.

I actually concede that taking the edges to the extreme teaches one a lot of things, like how thin behind the edge that blade can be without microchipping etc.
Natural stones are about finesse and one can learn more about them when taking your edge to the limit.
I, myself, like to do that too, but as a way to learn more about sharpening than as a need to have a performing blade at the kitchen.

When one falls in love with sharpening, it's hard to settle for just a blade that performs, the best possible edge feels like a necessity.