Behavior adjusting - noob questions

[Chris J]

Hi all,

I'm learning how to take care of my knives rather than abuse them because I'm tired of never having a good sharp knife.
I've got a Zwilling / Henckles Pro S 8" carving knife that I've been using since 2008. I understand it's considered a soft German knife and it's 55-58HRC. I have a few other Zwilling knives as well that are similar / smaller etc.

It often would get throw in the sink / dishwasher etc. I finally had enough and stopped that completely. Now it's hand wash only and gets kept separate from everything.
I've been primarily using a Zwilling steel to sharpen it and over time the blade ended up with quite a few nicks etc in it.

I did some reading on here and decided to buy an SP320 which removed 99% of the nicks and problems. I followed that with an SP1K and an SP1500. My guess is the 1500 is probably unnecessary but I've got it now.


My primary reason for posting is I'm not sure how to proceed going forward as far as the steel. Over the years I've used it every time before using the knife and it certainly made it cut better. However, I also know I was abusing the knife especially when cutting on dishes etc. I also feel I don't have good angle control when using the steel, even though it seemed to always result in a decent edge it honestly feels like a free for all while I'm doing it. Where as sitting at the table relaxing I can keep a pretty good accurate angle.

Would I be better off using the SP1500 to clean up the edge from time to time and just get rid of the steel completely? Would a higher grit stone like a SP5K be better for this task or a complete waste with German stainless??

Another question I have is Shapton says you can flatten their stones by rubbing two together, and they recommend using 3 I believe? Would it be safe to rub the 1K and 1500 together for flattening? I'm going to guess the 320 should be kept away from them?

 

[NickMinton]

IMO, your 1500 stone is plenty for softer German steel.

You can use the stone or the steel to maintain the edge and it’s helpful to try both and see which one works best for you.

Long story short, when the knife stops cutting the way you want it to after stropping on either the 1500 stone or steel rod (ex: it’s hard to cut tomato or pepper skins), it’s time to do another full sharpening

 

[Kawa]

The thing (for me atleast) with a steel is this:
it's hard to use the same angle freehand as you would with your stones.
If you hit the knife too shallow, the cutting will not improve. So you (unintentionally mostly) hit a too steep angle.
On a soft (German, but whatever) steel, this will create a new bevel, a microbevel. This is why the 'dull' soft wobly steel feels sharp again.
Nothing wrong with that per se, but the next time you sharpen on a stone, that microbevel has to get grind out. Could be a nasty job, concidering how long and often youve used the steel.

This all applies to 99% of the steel steels you can buy, the ones with grooves in it. They don't sharpen people say, but on soft steel it will remove metal.

If you want to use a steel for touchups, I would buy a decent steel. One that has some grooves, but not the very deep ones. Even Zwlling or Wusthofs steels are quite bad for this.
Dickoron micro (white handle) , thats the way to go. It will improve the cutting of soft stainless knives without creating a microbevel too fast.

I also have the Dickoron polish (blue handle), but that doesnt improve the cutting edge on soft stainless. I thinkg @Benuser succesfully uses them on soft carbons (which I dont have).

One other thing, 1000 gritt and 1500 gritt are to close to complete eachother, but you allready thought so.
It doesnt really matter which you use, but use one. The one you like most.

 

[Chris J]

The thing (for me atleast) with a steel is this:
it's hard to use the same angle freehand as you would with your stones.
If you hit the knife too shallow, the cutting will not improve. So you (unintentionally mostly) hit a too steep angle.
On a soft (German, but whatever) steel, this will create a new bevel, a microbevel. This is why the 'dull' soft wobly steel feels sharp again.
Nothing wrong with that per se, but the next time you sharpen on a stone, that microbevel has to get grind out. Could be a nasty job, concidering how long and often youve used the steel.

This all applies to 99% of the steel steels you can buy, the ones with grooves in it. They don't sharpen people say, but on soft steel it will remove metal.

If you want to use a steel for touchups, I would buy a decent steel. One that has some grooves, but not the very deep ones. Even Zwlling or Wusthofs steels are quite bad for this.
Dickoron micro (white handle) , thats the way to go. It will improve the cutting of soft stainless knives without creating a microbevel too fast.

I also have the Dickoron polish (blue handle), but that doesnt improve the cutting edge on soft stainless. I thinkg @Benuser succesfully uses them on soft carbons (which I dont have).

One other thing, 1000 gritt and 1500 gritt are to close to complete eachother, but you allready thought so.
It doesnt really matter which you use, but use one. The one you like most.

The Zwilling steel I have is pretty worn so most of the grooves are gone.
But, I still don't feel I can use it at the right angle, I have a feeling it's going bye bye.

Are you in agreement with stopping at 1000 / 1500 on knives like this, or should I buy a higher grit stone for polishing?

I suppose my fear is the steel allegedly doesn't remove much material, so I didn't mind using it all of the time. That's why I asked about a SP5K, I felt it could touch things up and not remove much. But, I also don't know enough to know if that's wrong and a complete waste.

I'm sorry if this is a silly question.

 

[NickMinton]

The Zwilling steel I have is pretty worn so most of the grooves are gone.
But, I still don't feel I can use it at the right angle, I have a feeling it's going bye bye.

Are you in agreement with stopping at 1000 / 1500 on knives like this, or should I buy a higher grit stone for polishing?

I suppose my fear is the steel allegedly doesn't remove much material, so I didn't mind using it all of the time. That's why I asked about a SP5K, I felt it could touch things up and not remove much. But, I also don't know enough to know if that's wrong and a complete waste.

I'm sorry if this is a silly question.

You’re really not gonna get much improvement beyond 1500 on the softer steels.

Carbon and higher HRC stainless varieties can hold and maintain the edges placed from finer stones

 

[Nemo]

Welcome to KKF.

Assuming that your knives are made from Westen stainless/ X50CrMoV/ Krupp stainless, the most common failure mode of the edge is for it to roll over. This would be corrected by realigning the edge with a steele. Having said that, as mentioned, steeles often also put a microbevel on the edge and this is probably more pronounced with abrasive steeles. This microbevel would indeed need to be ground out when sharpening on stones, making a "touch up" more difficult. The other issue is that if some of your knives are 58 HRC, you are getting towards the zone where edge failure can also occur by micro-chipping. This is a problem that you could actually cause with your steele.

FWIW, I never use a steele on Japanese knives, some of which are heat treated as low as 58 HRC.

Using a steele is not rocket science but you need to be slow, deliberate and gentle. Apply the knife to the steele at the desired angle and slowly and gently run the edge along the steele. Remember that the edge is tiny, so even a very light force will exert massive pressure at the edge. You don't need to go all Gordon Ramsay on the steele. Let it take 2 or 3 seconds to run the edge along the steele. This will help you develop and maintain angle control. If you hit the correct angle, you may only need a couple of runs on each side.

These Western stainless steels (not steeles) don't take a polish well. Your SP 1000 (maybe 700ish JIS?) would be an ideal grit for sharpening them. I would probably use the SP1500 only for the final stages of deburring. Avoid higher grits in these steels.

Having said all this...

Think about getting a Japanese (or Japanese style) knife.

Advantages:
1) Sharper edges due to finer grain and harder steel. Able to take a much higher polish to the edge.
2) Longer edge retention. Depending on the steel, it could be a lot longer.
3) A more tuned geometry means either a thinner knife that falls effortlessly through hard food or a thicker or a convex blade that ploughs through wet food without stiction. Or a middleweight that does a little bit of both. This is the bit that will blow your mind. Especially the first time you use a thin knife.

Disadvantages:
1) More fragile edges. Not a problem if you look after them properly. No hard/ frozen/ bony food, no knives left in sink and no dishwasher (actually, this applies to anything that you want to stay sharp).
2) Not amenable to steeling. But you can refresh the edge by stopping. Actually, you can do this on a Western knife as well.
3) Assymetric grinds mean that a knife is tuned mainly for right handers. This is less of an issue for very thin knives and left handed knives do exist but are less common and more expensive. See Kippington's excellent thread on assymetry to learn more.
https://www.kitchenknifeforums.com/threads/a-basic-explanation-of-asymmetry.33951/
4) In the very long run, you may need to learn all about knife geometry if you want to maintain the knife's geometry as you sharpen it. Or you could send it out for "thinning" periodically (probably only necessary once every couple of if you take this route).

 

[aporigine]

The Zwilling steel I have is pretty worn so most of the grooves are gone.
But, I still don't feel I can use it at the right angle, I have a feeling it's going bye bye.

Are you in agreement with stopping at 1000 / 1500 on knives like this, or should I buy a higher grit stone for polishing?

I suppose my fear is the steel allegedly doesn't remove much material, so I didn't mind using it all of the time. That's why I asked about a SP5K, I felt it could touch things up and not remove much. But, I also don't know enough to know if that's wrong and a complete waste.

I'm sorry if this is a silly question.

The only silly question is the one not asked. You’re already ahead by asking.

I have a growing stable of hard Japanese and Western-artisan knives, but I started with Henckels and still use them, especially on tasks that are tough on an edge, like stuff with bones or pizza. I do not sharpen them past Shapton 1k and use a steel on them to keep the edge dressed until I sense diminishing returns, at which point it’s time to reset the edge on the 1k (and perhaps thin behind the edge on Chosera 400.)

These Germans have fairly generous edge bevels, which makes them fairly thick behind the edge. This confers toughness but is not ideal for use on, say, onions or other soft produce. I have used coarse stones to blend the edge into the face for the first few mm of blade height. I find a big difference in how that makes them cut. The tradeoff is cutting feel vs. robustness.

Taking Friodur down to a zero bevel (essentially wiping out the edge bevel by thinning all the way to the apex) is not practical, but reducing the size of that bevel by 80-90% from the stout factory geometry is imo the sweet spot between cutting and standing up to use.

One of these days I’ll retire my Zwilling round steel and get a big Dick. (Yes; I’m twelve years old on the inside.) The thing to remember or practice is very light passes of edge on steel. The contact point is tiny, so it’s very easy to exceed the blade steel’s elastic limit. A steel does not sharpen so much as straighten a rolled edge.

My other suggestion is to have a flattening plate for your stones rather than rub disparate grits together. Cktg (Chef knives to go; a retailer I trust) sells a good one for pretty cheap. You can pinch-hit with a sheet of coarse sandpaper affixed to a known-good flat surface. Use a soft pencil to make a cross-hatch on the stone to monitor the flattening process. I do this very often. It’s a bit of an eye-opener how quickly even the very hard Shaptons go out of true!

Welcome to the rabbit hole. It’s very cozy but smells a bit rabbity down here.

 

[Chris J]

Welcome to KKF.

Assuming that your knives are made from Westen stainless/ X50CrMoV/ Krupp stainless, the most common failure mode of the edge is for it to roll over. This would be corrected by realigning the edge with a steele. Having said that, as mentioned, steeles often also put a microbevel on the edge and this is probably more pronounced with abrasive steeles. This microbevel would indeed need to be ground out when sharpening on stones, making a "touch up" more difficult. The other issue is that if some of your knives are 58 HRC, you are getting towards the zone where edge failure can also occur by micro-chipping. This is a problem that you could actually cause with your steele.

FWIW, I never use a steele on Japanese knives, some of which are heat treated as low as 58 HRC.

Using a steele is not rocket science but you need to be slow, deliberate and gentle. Apply the knife to the steele at the desired angle and slowly and gently run the edge along the steele. Remember that the edge is tiny, so even a very light force will exert massive pressure at the edge. You don't need to go all Gordon Ramsay on the steele. Let it take 2 or 3 seconds to run the edge along the steele. This will help you develop and maintain angle control. If you hit the correct angle, you may only need a couple of runs on each side.

These Western stainless steels (not steeles) don't take a polish well. Your SP 1000 (maybe 700ish JIS?) would be an ideal grit for sharpening them. I would probably use the SP1500 only for the final stages of deburring. Avoid higher grits in these steels.

Having said all this...

Think about getting a Japanese (or Japanese style) knife.

Advantages:
1) Sharper edges due to finer grain and harder steel. Able to take a much higher polish to the edge.
2) Longer edge retention. Depending on the steel, it could be a lot longer.
3) A more tuned geometry means either a thinner knife that falls effortlessly through hard food or a thicker or a convex blade that ploughs through wet food without stiction. Or a middleweight that does a little bit of both. This is the bit that will blow your mind. Especially the first time you use a thin knife.

Disadvantages:
1) More fragile edges. Not a problem if you look after them properly. No hard/ frozen/ bony food, no knives left in sink and no dishwasher (actually, this applies to anything that you want to stay sharp).
2) Not amenable to steeling. But you can refresh the edge by stopping. Actually, you can do this on a Western knife as well.
3) Assymetric grinds mean that a knife is tuned mainly for right handers. This is less of an issue for very thin knives and left handed knives do exist but are less common and more expensive. See Kippington's excellent thread on assymetry to learn more.
https://www.kitchenknifeforums.com/threads/a-basic-explanation-of-asymmetry.33951/
4) In the very long run, you may need to learn all about knife geometry if you want to maintain the knife's geometry as you sharpen it. Or you could send it out for "thinning" periodically (probably only necessary once every couple of if you take this route).

I'm surprised to see you say "The other issue is that if some of your knives are 58 HRC, you are getting towards the zone where edge failure can also occur by micro-chipping. This is a problem that you could actually cause with your steele."

That's exactly what happened with mine though I didn't know why or what it was called. It had chips out of it and was getting caught on rags etc. it was actually quite ugly. It took a decent amount of work even with the SP320 to get it cleaned up.

 

[Nemo]

I'm surprised to see you say "The other issue is that if some of your knives are 58 HRC, you are getting towards the zone where edge failure can also occur by micro-chipping. This is a problem that you could actually cause with your steele."

That's exactly what happened with mine though I didn't know why or what it was called. It had chips out of it and was getting caught on rags etc. it was actually quite ugly. It took a decent amount of work even with the SP320 to get it cleaned up.

So a couple of things are likely happening here:

1) As the edge rolls over and is straightened multiple times, it undergoes a process called Work Hardening. This makes it harder but more brittle and more prone to chip. Think of a paper clip the you bend backwards and forwards over and over again until it breaks. This is one of the practical limitations to how long you can steele between actual sharpening.

2) if your steele has ridges on it, these are like tiny crowbars slamming into the edge and taking bits out. Especially if you are using a decent amount of force while steeling.

 

[Chris J]

I'm sure this is a dangerous question, but if I want a decent knife that'll cut roast beef super thin, what would be a good place to start? Carbon steel is fine I don't mind taking care of it.

And how do I sell the idea of it and more stones to the wife.

 

[aporigine]

I'm sure this is a dangerous question, but if I want a decent knife that'll cut roast beef super thin, what would be a good place to start? Carbon steel is fine I don't mind taking care of it.

And how do I sell the idea of it and more stones to the wife.

For this I would choose a sujihiki — not as tall as a gyuto/chef, and made for just such a task as you describe. Very good examples can be had in stainless or carbon. If you have the space to fully exploit draw (pull) cuts, I’d go longer rather than shorter. I have two, both carbon clad in iron. One is very thin and the other of a stouter geometry. Both are 300mm blades. One day I want something very long, 360 or more. That’ll handle a big roast with long, single draw strokes and leave smooth pretty cut surfaces.

Thin (and a bit flexy) vs thicker and rigid is subjective, a matter of preference.

If you follow the “daily knife pics” and “what’s cooking?” threads, you’ll see a variety of styles and makers being put to use. It’s a good way to get oriented. I also click on just about every wts (want to sell) thread to find out about the spectrum of knives folks here use. Almost all the knives being sold are top-flight, but like shoes or cars, there is very little universal better or worse. It’s also worth noting that (unless you collect fir it’s for its own sake) price has more to do with supply and demand than with absolute quality. You can get a great knife for a hundred or so — if you know what you want, or are willing to “catch and release” for a bit of a loss, generally 10 to 20% of your purchase price.

dang spellcheck

 

[Nemo]

I'm sure this is a dangerous question, but if I want a decent knife that'll cut roast beef super thin, what would be a good place to start? Carbon steel is fine I don't mind taking care of it.

And how do I sell the idea of it and more stones to the wife.

If this is the only thing you want a knife for (spoiler: it isn't), you'll want a sujihiki (literally "flesh slicer"), a long but not tall in profile slicing knife.

As a value proposition, I like Shiro Kamo's kurochi series. Mine is from KnS ("Shinko Selian" Aogami Super) but other outlets sell other versions. IIRC, Cleancut sells a blue2 version called "black dragon". Decent grind, decent but rustic fit and finish. Has the basics sorted without any of the fancy (and expensive) bling.

But I don't think that you want a suji first up. A gyuto (literally "beef knife") is the Japanese take on a French profile chefs' knife. Only better. Although it's not optimised for slicing, it still does a decent job at it. And it does everything a chefs knife does only much much better. Once you start using a decent gyuto, you'll rarely use your Western knives again.

The Shiro Kamo Kurochi series is once again a good bet here but there are other similar knives that I haven't used that often get a recommend in this situation.

Be aware that if your roast is crusty, you'll need to be careful using a Japanese knife on it. There is potential to microchip the hard thin edge on the hard crust. I have a knife set aside for crusty roasts that is made from a very tough steel (YXR7) and this usually does OK. I have also used knives of more brittle steel and often got away with it, occasionally not. Nothing that a sharpening doesn't fix, though. If you'll be doing crusty roasts a lot, a more conservative (less acute) edge is a good idea.

How you justify your purchases is up to you. Some highlight the benefits of better food or easier cooking. Some use bribery (IIRC, handbags are often mentioned). Some have partners who just want the best for them, I guess

 

[sanmateo]

the slicer I keep in the knife block for the family to use is a zwilling four star 10", model 31070-260. Easy to maintain, tolerates the dishwasher, and I won't cry if something happens to it. I got mine for less than $30 on ebay. Victorinox and similar slicers work great, too, especially if you put a nice toothy edge on them. A nice suji won't automatically improve your knife skills, but it could be more fun.

also, I use an 'idahone' brand ceramic rod on all my western knives and tojiros. I adjust the angle depending on the knife and use, but every couple months I take them back to the stones.

 

[Chris J]

The Zwilling I have is a 31020-200
It says Friodur ice hardened. No idea if that's actually something or just marketing.

It sells for something like $120 so it's not an expensive knife but not dirt cheap either.

Cristy roast beef can chip a knife. I would've never thought that and it's good to know. I very often get a good crust on it and never thought anything of it.

 

[aporigine]

The Zwilling I have is a 31020-200
It says Friodur ice hardened. No idea if that's actually something or just marketing.

It sells for something like $120 so it's not an expensive knife but not dirt cheap either.

Cristy roast beef can chip a knife. I would've never thought that and it's good to know. I very often get a good crust on it and never thought anything of it.

Ice hardening is indeed a thing. It can be taken further by cryo treatment, a way to force the steel into austenite —> martensite transition. Martensite good.

I never get a crust on my roasts, so adjust your read of my opinions accordingly.

 

[Nemo]

The Zwilling I have is a 31020-200
It says Friodur ice hardened. No idea if that's actually something or just marketing.

It sells for something like $120 so it's not an expensive knife but not dirt cheap either.

Cristy roast beef can chip a knife. I would've never thought that and it's good to know. I very often get a good crust on it and never thought anything of it.

To be clear, I'm talking mainly about micro chips which dull the edge, not massive chips which ruin the knife or require significant repairs.

For the most part, that's what I'm talking about, anyway. I have seen (and indeed repaired) large chips but they were probably all caused by misuse (frozen food, bones, stone fruit stones, hard cheese rind, etc). FWIW (and touch wood) I have never personally caused any of these large chips.

 

[Kawa]

The Zwilling steel I have is pretty worn so most of the grooves are gone.
But, I still don't feel I can use it at the right angle, I have a feeling it's going bye bye.

Are you in agreement with stopping at 1000 / 1500 on knives like this, or should I buy a higher grit stone for polishing?

I suppose my fear is the steel allegedly doesn't remove much material, so I didn't mind using it all of the time. That's why I asked about a SP5K, I felt it could touch things up and not remove much. But, I also don't know enough to know if that's wrong and a complete waste.

I'm sorry if this is a silly question.

Using a steel for touch up is much more conveniant then using a stone. A handfull of diehards in here have their Arkansas in the back pocket, always ready to do a touchup with the stone in one hand and the knive in the other. Thats not for us.
I believe one of the philosophy-points of the soft Germans is 'being able to steel in between'. Thats their choice to make the knife like that.
You can abuse it more, more user friendly. Trade off, its not that delicatie or sharp.

I would stop at the 1000 or 1500 (I dont think between those, it matters that much in practise). Like being said, if you go higer, the knive will not support that.
meening, it will be dull (a true slick feeling on the edge) after one meal. I did try a 8000 stone in the beginning (hey, ive learned) because I wanted the knife as sharp as possible. Not gonna work for long.
So no, I wouldnt buy a sp5k for touchup on a german.

Like being suggested, I would look for a Japanese style knife. Even though you mention 'cutting beef', i still would start with a Gyuto. You can do everything with that knife, including slicing beef. If you only do a beef-slicer, you will not experience the true nature and differences of a German vs a Japanese.
Next plus is, you can use higher gritt stones on the Japanese, which is more fun while sharpening

 

[Benuser]

A few remarks. Your Zwilling steel rod may be worn to some extend, it still is a rather aggressive tool. In fact, you're redressing steel that has failed, and fatigueing a bit of fresh steel as well. An edge made of failing and fatigued steel won't last. In fact, the times you need the steel become closer every time.
An extreme example. Using a soft carbon on a crappy poly board. A fatal combination. Fresh from the stones, it holds well for an hour. Using a well-worn grooved added twenty minutes; then, only ten minutes, and so on.
If you insist on using a steel rod, have the Dickoron Micro. If properly used, it may postpone a stone sharpening for a long time. But with the stone sharpening, more fatigued steel has go get removed. In practice, you will have so start with a coarser stone.

Stone sharpening German soft stainless is no fun at all. As others have rightly told, it doesn't hold any refinement. The entire job is to be done with a Shapton Pro 1k or a Chosera 400, who have similar grits.
The problem is in achieving a full deburring on a relatively coarse stone. Far from easy.

Anyway, if you come from a soft German, you will have to realise that hard, thin edges don't support lateral forces. Exit the steel rod. You may maintain the edge with your finest stone. That will be in the 4k-area. A few strokes will do.

I would suggest to open a new thread looking for an appropriate 21cm gyuto. Not necessarily with a Japanese handle. They have become much more popular for export these last years: but a Western handle can offer better value.

A last remark on roasts: a sujihiki is great fun, and is surely more adapted. But it will get much less use. First get a decent gyuto, and learn to sharpen and maintain it. You may very well cut your roast with a gyuto.

By far most knives come with poor, weak factory edges. Your first task will be sharpening it, or having it done by the retailer.

And concerning crusty roasts: use the sharp heel to make a first insertion. It will save your edge.

 

[Benuser]

P.S. Two stones who are all you need.
The 800 is extremely versatile: from maintenance thinning to one and only if you wish so. Their abrasive agents break down and offer a 1200 end result. Well worth to play with it and find out how varying pressure, water and mud may change its behaviour.
The 3k ends at at least 4k. Silky feeling, a very regular scratch pattern.
Both stones do offer a tremendous feedback, meaning that you feel when the very edge is reached, and also feeling whether the burr is gone or not. Very convenient stones if one looking for convexed edges.

You already have a 320 for thinning and repairs. All you need apart from these stones is an Atoma 140 for flattening.

https://www.kitchenknifeforums.com/threads/naniwa-800-and-3000.76239/

 

[Chris J]

P.S. Two stones who are all you need.
The 800 is extremely versatile: from maintenance thinning to one and only if you wish so. Their abrasive agents break down and offer a 1200 end result. Well worth to play with it and find out how varying pressure, water and mud may change its behaviour.
The 3k ends at at least 4k. Silky feeling, a very regular scratch pattern.
Both stones do offer a tremendous feedback, meaning that you feel when the very edge is reached, and also feeling whether the burr is gone or not. Very convenient stones if one looking for convexed edges.

You already have a 320 for thinning and repairs. All you need apart from these stones is an Atoma 140 for flattening.

https://www.kitchenknifeforums.com/threads/naniwa-800-and-3000.76239/

How does the Atoma 140 compare to the Atoma 400 for flattening?
Would the 400 be a mistake or just a little more time consuming?

 

[Benuser]

How does the Atoma 140 compare to the Atoma 400 for flattening?
Would the 400 be a mistake or just a little more time consuming?

Have never tried the 400. There were some discussions about using the 140 with very fine stones as it obviously will leave a different surface. Not necessarily a problem. I use it with 8k stones. They get a bit faster until the surface has got smooth again.
Now the coarse stones. To avoid fast wearing I don't use the 140 with lower grits than 320. Something similar is likely to be the case with the 400. My guess would be not to use below a 600 grit. But users who do have the 400 may tell you.
Anyway, if you already have a 400 that may work with a wide range of stones.

 

[Chris J]

Have never tried the 400. There were some discussions about using the 140 with very fine stones as it obviously will leave a different surface. Not necessarily a problem. I use it with 8k stones. They get a bit faster until the surface has got smooth again.
Now the coarse stones. To avoid fast wearing I don't use the 140 with lower grits than 320. Something similar is likely to be the case with the 400. My guess would be not to use below a 600 grit. But users who do have the 400 may tell you.
Anyway, if you already have a 400 that may work with a wide range of stones.

Right now I have nothing.
My only stones are the SP320,1K and 1500.
I had some cheaper Arkansas stones I just got rid of. No idea how good or bad they were, but I never liked them and they didn't seem to do much. I originally used them with water, and then switched to oil and still didn't like them.

That could have been 100% my fault, but to be honest I don't really care either way because I'm much much happier with the Shapton's.

The reason I asked about the 400 was it seems easier to find online than the 140.

 

[Benuser]

If you have the choice, get the 140.

 

[kujaku]

I use both the Atoma 140 and 400, but the 140 is more versatile. The 140 can be used for flattening coarse stones, and sometimes with the 400, when flattening higher grit stones, it can become sticky and hard to move (especially Kitayama 8k).

If you're concerned about the diamond on the Atoma wearing out while flattening coarse stones, you can use a glass plate + SiC powder, or rub the coarse stones together to flatten them.

 

[aporigine]

I use both the Atoma 140 and 400, but the 140 is more versatile. The 140 can be used for flattening coarse stones, and sometimes with the 400, when flattening higher grit stones, it can become sticky and hard to move (especially Kitayama 8k).

If you're concerned about the diamond on the Atoma wearing out while flattening coarse stones, you can use a glass plate + SiC powder, or rub the coarse stones together to flatten them.

Trouble with rubbing two stones together, especially of different grits, is you’ll get a matched pair: one dished, the other domed. A diamond plate is a sure thing.

 

[Chris J]

Trouble with rubbing two stones together, especially of different grits, is you’ll get a matched pair: one dished, the other domed. A diamond plate is a sure thing.

I've never done it, but I assumed you would rotate the stones as you go to cancel out differences?

 

[aporigine]

I've never done it, but I assumed you would rotate the stones as you go to cancel out differences?

Spherical aberration cannot be corrected that way. The makers of optical flats got their results by grinding three blanks (same size; same material) in rotation. A against B, AC, then BC, rinse repeat.

 

[Chris J]

Spherical aberration cannot be corrected that way. The makers of optical flats got their results by grinding three blanks (same size; same material) in rotation. A against B, AC, then BC, rinse repeat.

I guess that's where Shapton's recommendation of 3 stones comes from.
Interesting.

 

[Benuser]

I use both the Atoma 140 and 400, but the 140 is more versatile. The 140 can be used for flattening coarse stones, and sometimes with the 400, when flattening higher grit stones, it can become sticky and hard to move (especially Kitayama 8k)

Interesting point. A lot of very fine are indeed sticky — the Naniwa Junpaku 8k, the Shapton Pro 12k — as I noticed when sharpening, I really have to remove slurry from the bevels. I do it with my nail, but would like to hear a safer method.

 

[kujaku]

Trouble with rubbing two stones together, especially of different grits, is you’ll get a matched pair: one dished, the other domed. A diamond plate is a sure thing.

100% agree.

as I noticed when sharpening, I really have to remove slurry from the bevels. I do it with my nail, but would like to hear a safer method.

Sorry, I don't understand this part.