My Jnat Journey

[Tomo]

This was exactly what I got from the thread. It didn't put me off -- it made me think of them as more approachable. I have some stones on the way now (purchase decision heavily inspired by this thread), so we'll see how that revised option bears out in practice

Good luck with it. Keep us posted on your progress.

 

[Tomo]

Cutting JNats is a risky business. You can easily end up with more prices than you bargained with. I went with a dry hacksaw cut outside as recommended. I wanted to clean up some of the jagged ends and remove some sections of toxic lines. The soft Kitta cut easily enough. The Asagi on the other hand was pretty hard and cleaved into several pieces. It basically self destructed. I’m now understanding why we need to seal these stones and treat them with care. There are some usable Asai chunks just smaller than I was hoping for.

 

[H Brad Boonshaft]

Try reversing your hack saw blade, so it cuts on the push stroke. If you try to cut traditionally on the push stroke with the blade reversed the saw is not cutting but scraping the material from the kerf. If pressure is used on the push stroke, it is only cutting on the pull stroke where no pressure is use and minimally cutting.

Additionally use a blade with more teeth (TPI, Teeth Per Inch) a saw is designed to cut the material with each tooth, (visualize a row of chisels) and drag the saw dust to the edge of the material and fall out of the gullet of the saw blade. The gullet is the U or V shape where the tooth is cut from the edge of the blade.

The fewer TPI the larger the teeth and more importantly the larger the gullet. Once the gullet is filled, impacted with saw dust it limits the cutting ability of the teeth and overheats the blade and the cutting material. Once the teeth are filled/impacted, the saw stops cutting. Typically, the sawyer uses more pressure, and bad things happen to the cut finish, the blade and the material. Where have we heard that before?

You can buy hacksaw blade with as few as 14tpi almost half as many teeth as your 24tooth blade and more importantly with teeth twice as large, and gullets twice as deep and wide. Allowing it to hold and remove twice as much sawdust.

Hand sawing is one of those lost arts. The trick is to match the saw TPI, (tooth size and number of teeth), tooth filed cut angle, (rip or cross cut), the tooth set, (the individual teeth are alternately bent away from the blade to cut a wider kerf and again move more saw dust and keep the saw from binding in the cut, kerf, to the material being cut. Let the saw do the work a properly sharp saw will cut with minimal pressure and cut straighter.

Hack saws are designed to hold the blade under tension and cut on the push stroke, to cut hard material, like steel. Pull cut blade are thin blades that are designed to cut on the pull stroke, the blade is thin and not under tension.

In short use a 14TPI blade and ensure the saw teeth are pointed forward. You can cut several stones with a single saw blade before it goes dull, stones will dull a blade, but most blade are hardened and pretty tough, (by design to cut steel). Secure the work use a clamp to hold the work, half the battle and let the saw do the work.

Hack saw blades are inexpensive.

 

[Tomo]

Try reversing your hack saw blade, so it cuts on the push stroke. If you try to cut traditionally on the push stroke with the blade reversed the saw is not cutting but scraping the material from the kerf. If pressure is used on the push stroke, it is only cutting on the pull stroke where no pressure is use and minimally cutting.

Additionally use a blade with more teeth (TPI, Teeth Per Inch) a saw is designed to cut the material with each tooth, (visualize a row of chisels) and drag the saw dust to the edge of the material and fall out of the gullet of the saw blade. The gullet is the U or V shape where the tooth is cut from the edge of the blade.

The fewer TPI the larger the teeth and more importantly the larger the gullet. Once the gullet is filled, impacted with saw dust it limits the cutting ability of the teeth and overheats the blade and the cutting material. Once the teeth are filled/impacted, the saw stops cutting. Typically, the sawyer uses more pressure, and bad things happen to the cut finish, the blade and the material. Where have we heard that before?

You can buy hacksaw blade with as few as 14tpi almost half as many teeth as your 24tooth blade and more importantly with teeth twice as large, and gullets twice as deep and wide. Allowing it to hold and remove twice as much sawdust.

Hand sawing is one of those lost arts. The trick is to match the saw TPI, (tooth size and number of teeth), tooth filed cut angle, (rip or cross cut), the tooth set, (the individual teeth are alternately bent away from the blade to cut a wider kerf and again move more saw dust and keep the saw from binding in the cut, kerf, to the material being cut. Let the saw do the work a properly sharp saw will cut with minimal pressure and cut straighter.

Hack saws are designed to hold the blade under tension and cut on the push stroke, to cut hard material, like steel. Pull cut blade are thin blades that are designed to cut on the pull stroke, the blade is thin and not under tension.

In short use a 14TPI blade and ensure the saw teeth are pointed forward. You can cut several stones with a single saw blade before it goes dull, stones will dull a blade, but most blade are hardened and pretty tough, (by design to cut steel). Secure the work use a clamp to hold the work, half the battle and let the saw do the work.

Hack saw blades are inexpensive.
View attachment 1918730

Thanks for the detailed response. I had no idea.

 

[Tomo]

Well I was afraid this would happen. I went back to my favourite Arkansas stone and had a shave from it. It was good but it was no Jnat edge…

 

[Tomo]

A rainy day today so I spent some time with my Jnats. Firstly I lapped the Ozuku some more. I don’t like wasting stone but the surface weirdness was bugging me. I managed to lap past the flakiness. It turned out to just be at the surface. I think it’s looking a lot better now.

 

[Tomo]

Next I played around with some of the harder Nagura. I had some issues with these scratching my base stone so I inspected them for any sharp corners an and smoothed them out. I used less pressure in building the slurry and satisfied myself with a thinner slurry.

I found that these hard Nagura slurries were capable of totally erasing any previous Kasumi finish and could lead to a near mirror polish. The HHT was good but no better than the hazy bevel. I suspect much of the Jnat smoothness was lost. The hazy bevel finish actually seemed to have a bit more bite. I’ve come to the conclusion that Jnat finishing may not be about erasing all of the previous stria like a synth honing progression is. It’s probably more about tuning into a sweet spot than it is about maxing things out.

 

[albsat]

@Tomo

I enjoy reading your journey journal. How many JNAT do you have currently in your rotation?

 

[Tomo]

@Tomo

I enjoy reading your journey journal. How many JNAT do you have currently in your rotation?

Quite a few of you count the little ones. They seem to be multiplying!

 

[JPO]

Quite a few of you count the little ones. They seem to be multiplying!

View attachment 1919634

Nice collection.
You have not started with mid-range stones yet
I recently got two Namito mid-to upper mid-range stones. I enjoy my naguras. Howver, i think they are a solution looking for a problem.

 

[Tomo]

Nice collection.
You have not started with mid-range stones yet
I recently got two Namito mid-to upper mid-range stones. I enjoy my naguras. Howver, i think they are a solution looking for a problem.

Thanks. There’s plenty to work with.

 

[rhgg2]

Thanks for the detailed response. I had no idea.

A carbide blade is I think gentler as it has no teeth at all to catch, it's basically a rod that's been plated with SiC. It cuts on both the push and pull stroke and generates less heat. Downside is the kerf is quite thick so you lose a bit more stone (if you want to keep both pieces).

 

[Tomo]

Jnats seem to be a bit like golf. As soon as you think you have it all figured out you get a curve ball.

I think I did too much testing on this razor and screwed the bevels. I reset things with a 1k, 3k, 10k Shapton Glass progression and then went to the Mikawa set on the Ozuku. Finished on a 1200 Atoma Slurry. I was not getting anywhere with the hard Tomos.

The resulting edge is nice. I’m still figuring out the Ozuku. I don’t think this is my finest Awasedo but a nice edge can be developed with the right technique and light pressure. There is always a mild grinding sensation.

The razor is a beater but I enjoy the size and feel. I recently noticed that it has a double belly grind. It takes a good edge. The JNat slurry is polishing it up to a nice sheen.

 

[Christian1212]

Jnats seem to be a bit like golf. As soon as you think you have it all figured out you get a curve ball.

I think I did too much testing on this razor and screwed the bevels. I reset things with a 1k, 3k, 10k Shapton Glass progression and then went to the Mikawa set on the Ozuku. Finished on a 1200 Atoma Slurry. I was not getting anywhere with the hard Tomos.

The resulting edge is nice. I’m still figuring out the Ozuku. I don’t think this is my finest Awasedo but a nice edge can be developed with the right technique and light pressure. There is always a mild grinding sensation.

The razor is a beater but I enjoy the size and feel. I recently noticed that it has a double belly grind. It takes a good edge. The JNat slurry is polishing it up to a nice sheen.

View attachment 1920537

Another thing to watch out for is making sure your slurry stays wet enough. Sometimes a person can be working the slurry for awhile and it the slurry becomes to thick, resulting in a killed edge.

 

[JPO]

Jnats seem to be a bit like golf. As soon as you think you have it all figured out you get a curve ball.

I think I did too much testing on this razor and screwed the bevels. I reset things with a 1k, 3k, 10k Shapton Glass progression and then went to the Mikawa set on the Ozuku. Finished on a 1200 Atoma Slurry. I was not getting anywhere with the hard Tomos.

The resulting edge is nice. I’m still figuring out the Ozuku. I don’t think this is my finest Awasedo but a nice edge can be developed with the right technique and light pressure. There is always a mild grinding sensation.

The razor is a beater but I enjoy the size and feel. I recently noticed that it has a double belly grind. It takes a good edge. The JNat slurry is polishing it up to a nice sheen.

View attachment 1920537

I think you would have gotten better results if you skipped the nagura progression after the 10k, and just finished with tomo slurry.
Another alternative is to do a nagura progression after the 3k.
Some of these hard stones tend to glaze a little. So, dressing the surface with either a diamond plate or a nagura can help.
If i use a diamond nagure it's used to replace a nagura progression. It's not a replacement for a good tomo for finishing.

 

[Frank Shaves]

Diamond slurry is totally dependent on the “quality” and performance of the base stone, and the grit of the diamond plate.

@H Brad Boonshaft makes a good point. I have been using the red 1200-mesh one of these to make JNAT slurry with no problems. I have never tried using the coarse 325-mesh plate to make JNAT slurry, but I assume the particle size will be larger using the coarser plate. I also gently rubbed the plate on a piece of very fine sandpaper before using the plate.

 

[Tomo]

I think you would have gotten better results if you skipped the nagura progression after the 10k, and just finished with tomo slurry.
Another alternative is to do a nagura progression after the 3k.
Some of these hard stones tend to glaze a little. So, dressing the surface with either a diamond plate or a nagura can help.
If i use a diamond nagure it's used to replace a nagura progression. It's not a replacement for a good tomo for finishing.

I take your point. My impression is that the Atoma slurry does not give as fine of an edge. My issue is that my Tomos fall into two categories; soft and easy to slurry / very hard and impossible to slurry.

I tried again today with one of the softer Tomo stones. This stone is probably not as fine as the hard Tomos but the edge feels more exciting than the Atoma slurry attempt. I need to find a stone that is both soft and fine.

 

[rhgg2]

I think the hard tomo need careful shaping. I find the scratches mostly come from tipping the tomo up to slurry on one edge and then catching a corner. Even when the corners are super rounded this is still a live risk. So, rather than making mine flat with broad chamfers and slurrying at an angle, I find it easier to have the whole surface convexed along at least one axis so it's usable flat. Any tipping is then fairly gentle and just following the radius of curvature of the face. Gamma has a good video about shaping tomo.

 

[Tomo]

I think the hard tomo need careful shaping. I find the scratches mostly come from tipping the tomo up to slurry on one edge and then catching a corner. Even when the corners are super rounded this is still a live risk. So, rather than making mine flat with broad chamfers and slurrying at an angle, I find it easier to have the whole surface convexed along at least one axis so it's usable flat. Any tipping is then fairly gentle and just following the radius of curvature of the face. Gamma has a good video about shaping tomo.

Do you use a lot of pressure with the hard Nagura?

 

[Christian1212]

1 trick is to let your hard tomo sit in water for 5 to 10 minutes before use. Will soften it up and make raising a slurry easier. Also slightly tilting the tomo helps as well.

Also check out tomonaguras / Keith's videos. He has a few about tomos and using different naguras.

Will note after the asano nagura progression I like tomfreshly lap my base stone. This helps revove the surface and can also help build slurry a bit easier.