Thread: Learning Jnats with Microscope

Euclid

thanks for the answer. I agree, but what I would like to understand is if my stone (remembering that it is a rather cheap Koppa) offers adequate performance or if can get more using another stone (of the same type, ie Nakayama). I say this because I have no terms of comparison and (apart from a better shape and size, which allow me to work more comfortably) sooner or later I'll have to decide whether to buy another one or not.
I am not very interested in hardness (with all the naguras I have available , I will easily find the one that pairs well with any hardness of the base stone, as long as this hardness is obviously between Lev. 4 and 5), but rather in finesse. For this reason I'm planning to do a water-only test and thus see what the stone's performances are without the intervention of the naguras. This would serve to have a term of comparison for the possible future evaluation of another stone.

Of course, as you said, I'll have to work on my technique (however already significantly improved thanks to your suggestions) to squeeze the best out of every single element used during my honing sessions. Practice is never too much!

This stone, Nakayama Kopa Kita appears to be a good stone that can produce a nice finish, based on the photos.

Keep in mind that a lot about Jnats is opinion. The seller rates the stone based on his opinion, often we know nothing about the seller’s experience. Jnats are also, “rated/priced on size and color/appearance, both of which may mean nothing as related to performance.

All that counts is performance, and there are many good stone that are relatively inexpensive. You do not need a large stone to finish a razor. So, if the stone is large enough to finish on comfortably and it produces a shaveable edge, that is all that counts, unless you get into collecting.

You should use proper terms when referring to your stones, to avoid confusion, Nakayama, it the mine, Kopa is the size and Kita is the color or appearance and the layer or strata is unknow. So, a stone from a Nakayama mine can be from any number of strata and can have varied color or appearance. I would refer to your stone as a Kita or Nakayama Kita. We know which stone you are talking about but others reading this thread may not.

The provenance of most Jnats is suspect as many stone were mined decades ago and sold several times before they land in our hands. But some information, like appearance and size are knowable, which mine a stone came from, only a few experts can tell for sure by looking at the stone, and it does not matter, if the stone is a performer.

You are getting good edges and experimenting with slurry, pressure, pre finish and other techniques you will be able to squeeze out better edges.

Slurry itself is a deep rabbit hole. One can simply make a thickish slurry and thin it to produce a good shaving edge. But if the razor is pre-finished to a higher level, 8-12k, then the Jnat only needs to finish the bevel and edge. It is a different slurry needed because not much steel needs to be removed or polished.

Slurry is a double edge sword, it cuts the bevel but at the same time is impacting the edge. So, let’s say that the slurry is X grit cutting/polishing the bevel. If you held in the air a piece of Wet & Dry sandpaper of X grit and repeatedly hit the sandpaper edge first as if attempting to cut the paper, what would that do to the edge?

That is what slurry is doing to your edge, you are polishing the bevel to create an edge, and slamming the edge into the slurry grit at the same time. Agreed, not to the same level of aggression as the sandpaper, but it is happening.

Technique is how you overcome that problem and learn to squeeze performance from your stones, and slurry. I can tell you thick or thin slurry, but what is thick, or thin, when do you reduce/thin your slurry, how do you reduce, add water, remove slurry or both? You must discover these limits for yourself, and you will.

Yes, you can buy other stones, but rarely that is the answer, better to learn the stones you have, master them, then look for something different if you feel the need.

I am always amused of videos of guys with large stone, then they hone with only 3-4 inches of stone in the middle.

You go to war, with the army you have.

Originally Posted by Euclid440

This stone, Nakayama Kopa Kita appears to be a good stone that can produce a nice finish, based on the photos.

Yep! that's exactly what I wanted to know, as I've not tested tens or hundred of stones to estabilish if my stones are fine enough. I can "believe" they are... but the opinion of a waaaaay more experienced mentor make me feel better
If I ever will test another finish stone... that's will be a good reference starting point.

I'm perfectly aware the way Jnats are graded by vendors or users and that actually it's hard to find an affordable one who rates them the right way, don't thinking just to gain money...
So, my possible questions to a (trusted) vendor would be: "I don't care of stamps or name or colors but.. Is that stone good for straight razor? Is it very fine? Is it a good finisher? How hard is it?".

Regarding the other "rabbit hole", i.e the slurry... I'm here to learn and (when will I finish testing Naguras with Nakayama Kiita and Ozuku (Asagi?)) when you deem it appropriate, I will try to follow and put your indications into practice sisematically as I'm doing with Naguras.

Donato, you have made very good progress for your short time honing and honing with Japanese Naturals. You are getting good looking and acceptable shaving edges with this stone, your tomo and technique.

So, you have a good base. I would do a 1k, to Diamond slurry, remove 1k stria and finish on the same slurry with each of your base stones. Try to grade/rant each of your base stones.

Then take your best performing Tomo, the Kita, Asagi, Suita and Mejiro Mikawa, I think. See if those tomo improve each of the base stones. Shave test each tomo edges for a full comparison.

This will show which combinations are the most consistent performers and rank each of your base stones. By the time you are finished, you should have a good working knowledge of your stones at hand.

Then you can experiment with slurry and come up with a Tomo progression. Experiment minimizing the nagura progression to the Tsushima and 2-3 other nagura. You will want to spend a little more time on the finishing laps as you thin slurry, trying to maximize each nagura slurry.

Do not be afraid to lightly joint the edge just before the final laps, strop on linen and reset the edge with your final laps of each nagura. Test you edges to see how quickly you can bring back the edge, with a minimum of slurry, minimize edge impact. I simply test by grabbing a single hair at treetop, at the toe, middle and heel. Do not cheat yourself, if it does not grab a hair, that is a failure. Do not re-test, try to grab another hair. Go back to the stone and do 6-10 more laps and test again.

You will rank your base stones and nagura and work on perfecting the best, of the best in nagura and each slurry.

Keep in mind you already have a combination for a good/decent shaving edge, that is probably better than most folks are getting from synthetic stones, this is your base line.

You will then start deep into the rabbit hole in search of the 2 percent and maximizing your knowledge of your best stone and nagura and try to minimize the progression at the same time. If it is simple, it is repeatable.

You have been systematic in your testing, continue to do so.

Good work.

Euclid

I will need a lot of time to to assimilate such a load of wisdom and knowledge. But I've been lucky: I found a Master who teaches me... so my duty is to learn.
I will never stop thanking you!

Here's an interesting experience I made yesterday with a razor I bought (from the States) last January. I honed it at time on a King 1K -> Diamond Slurry on my Aiiwatani Karasu (base stone), followed by Shobudani's slurry. I shawed with it a couple of times, but the shaves were just "decent", nothing more. I was starting to use the Jnats, but in reality, I was groping in the dark, until Euclid440 literally took me by the hand and started guiding me in the fascinating and complex world of Japanese stones and sharpening in general.

Yesterday, when I put the razor under the microscope, I saw a strange aspect in one zone (toward the toe) of the bevel. Sincerely I don't know if I made it or if there was already a portion of enlarged bevel, as I saw there was a sort of "double bevel" that I could have created during the previous honing, on a pre-existing situation... The remaining bevel was normal.

Anyway, I took that portion as a reference point for yesterday honing session. Last microscopic image is a control sample of another portion of the bevel.

The Razor: Henckels (carbon steel) 401 Platinum - 5/8" FH

This Time I used (1 Kapton tape) my Ozuku (Asagi?) as a base stone, followed by slurry of Tshushima/Asano Mejiro/Ozuku Suita Naguras. I.e the same sequence I used on Gong Razor I posted some days ago, which had given excellent results.

Microscopic and test shave results were as expected... i.e. very satisfying. The shave was close, quite smooth and post shave excellent.

This shows that, although I still have a lot to learn, having adopted a systematic operational criterion (under the careful guidance of a skilled Master) begins to give repeatable results (and to get a narrow bevel ).

I'm very Happy today!

Yes, it does look like a double, possibly a triple bevel.

Two thing may be happening, 1. The heel needs correction, it does look like you may be riding on the stabilizer, note arrow. Either way I would correct the heel and bring the corner of the heel edge well away from the stabilizer.

Use a coin to mark a radius like the one shown in the photo then cut the corner with a diamond plate. The metal is thin and will cut easily, shape to a pleasing arc.

2. You may be or did flex the blade while honing. On very hollow ground blades it is easy to flex the blade and hone on the back of the bevel, lifting the edge off the stone. It will create a double bevel, when you hone over it with less pressure it creates a third bevel until the whole bevel flattens out.

Not a big deal, and easy 5 minuet fix. There are many posts on heel correction. Once corrected the corner will be away from the stabilizer and allow the whole edge to lay on the stone.

Just watch your pressure on that razor, they are thin hollow ground, that is what makes them such great shavers. The new bevel does look good though.

I, by no means consider myself an expert on Jnats. I have only been experimenting with them for about 5-6 years.

My first foray into Jnats, a small Kita and Mikawa progression was not a big hit for me. It was only until I watched some of Alex Gilmores videos and he posted stone testing videos, where he set a bevel on a King 1k and finished the razor on diamond slurry. A simple 2 step process, Alex did not even bother to fully remove all the deep 1k stria but produced great shaving edges on a variety of vintage razors. Alex demonstrated how simple and basic honing on a Jnat could be. Up until then it just seemed so complicated and fussy.

I came from learning to hone a razor on a 6-inch translucent, talk about simple, water or a drop or two of oil and rub the razor on the stone. And produce a smoking edge. The Jnat is the only stone that could ever produce an edge that rivaled an Ark edge. Paste can come close but not as comfortable as a Jnat or Ark. I finish all razors on Arks or Jnats now.

Once Alex opened the door, I looked for photos of great Jnat edges. The best I have seen were from Alex Gilmore, Oz and Doc226. Those are the bevels and edges I try to emulate. But as I have said, how a bevel looks, does not guarantee a great edge, but it for me is a good indicator, if everything else is done right.

I probably have 10 or 12 Jnats and lots of tomo nagura, none of my stones are high dollar stones, most are Kopa or a bit larger, most are about $100 stones some $20-30, and the most expensive probably in the $250 range.

My favorites are a small Kita, hard Iromono Kita, Karasu Asagi. Large clean Asagi and a small Suita. Typically, I set the bevel on a 1k, usually a King and jump straight to the 8k, old crazed Naniwia Snow White.

From an 8k pristine bevel I use a Tsushima nagura to a Tenjyou and finish on a small hard Asagi or Koma nagura. All on the same base stone.
Keep it simple.

Euclid

I forgot to ask you if the heel had to be modified... and however you answered me
Anyway yesterday I was careful not to let the stabilizer touch the stone. Also don't think it was the problem as I made a double bevel already on the first time... but didn't add tape to do it.
Also I don't think I applied too much pressure (being a 5/8" that blade is quite stiff, despite the fact it's a full hollow). Of course I can be wrong.
Probably at that point, the bevel was enlarged during the restoration.


Regarding this statement: "I, by no means consider myself an expert on Jnats. I have only been experimenting with them for about 5-6 years."

Well... it's just... 5-6 years more than me!

After testing 7 different Naguras (plus Tsushima) I was really curios to see how the base stone (Nakayama Kiita Koppa) would work with a.... "Water Nagura" after the Tsushima.

So today I tested it water only and under running water. I stopped each section when I felt that the blade was sliding with increasing difficulty on the stone because of the sticking effect. So, under running water I was able to make just very few strokes.

I am not skilled enough to properly evaluate the microscopic results (I just notice the darker part of the bevel, whick should means it's polished (?)) but, to get a better idea, I checked the bevel with a 40X Loupe too, and it appeared homogeneously shiny, with really very fine (almost invisible) sharpening marks.
BTW. the usual "reference point" I used until now (the edge chip) has been completely eliminated.

The blade passed easily finger & treetop test.

Shave test scheduled for tomorrow.