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sigma 3k / 10k apexing difficulties of wear resistant steels

Posted by JSCT 
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Re: sigma 3k / 10k apexing difficulties of wear resistant steels
July 06, 2020 02:31AM
As a response, in general here is how I view sharpening :

-set the edge with the highest grit you can, that gives a tolerable time (1k King)

then

-set the apex with the necessary grit (600 DMT)

That is it, there are only two steps, and two stones in general, and the first step does NOT touch the apex at all, except in extreme cases. That edge should push cut newsprint and shave hair above the skin. If it didn't then the edge on the 1K was not fully formed or it was over ground with too much pressure and burred.

The only time I use more stones is because the first stone had to be really coarse to remove damage, or the apex grit is really x-fine so you can't even jump from the 1k King (you can't jump from the 1k to 8 k for example, well you could but you will do more work than if you used an intermediate stone). In that case you might see something like this which is an extreme case :

Set the edge :

-100, if this doesn't release grit, it will likely leave a large burr, a weak bond high slurry stone ideal, a DMT is the worst choice possible

Refine the edge and minimize the burr (note this doesn't set the apex) :

-400 Naniwa, this HAS to be a very muddy stone to minimize the burr, fine India would be a horrible choice
-3k SPS II, arkansas would be a horrible choice here

(if the 100 is a weak bond stone, you might be able to make both of those a 1k stone, but you would have to be perfect)

(note when I say horrible choice, I don't mean they are horrible stones, I mean they are horrible choices for that purpose, just like if you want to win a powerlifting meet, inviting marathon runners on your team would be a horrible choice, doesn't mean they are not exceptional athletes)

Now finally set the apex :

-mxf DMT

If you apex on any stone before the final, you will make later work much harder. As well, trying to actually get a knife to be sharp off of a weak bond stone (one that releases grit) is an involved process, this is how I figured out you have to do it :

[www.cliffstamp.com]

"And at that point is catching hair above the skin and can do push cuts, it has long passed what most people consider arm hair shaving sharp. I think this might be useful in general, I will likely try to repeat it on the Naniwa Superstone 400."

That isn't scraping, it is shaving with no contact to the skin, and true push cuts on newsprint.


If I had the stones you had in the video, I would do something like this :

-1200, edge set

That stone looks like it releases little to no abrasive, so it is very likely going to make a large burr if you over grind, so I would be very careful to try to not do that. If you do have a burr you can actually feel, the 3K can't remove that when dry. If you have a burr you can feel off the 1200 the 3K might struggle to remove it even when it is soaked and generating slurry. You might have to remove it on the 1200 and back sharpen.

-3K, soak it, go very light at the same edge angle, use the slurry to minimize the burr

If it doesn't happen when the edge is refined, do

-1 to 2, ultra light passes, short, alternating sides

By ultra light I mean you barely make contact, then

-go back to the original angle, and make a few passes to grind the micro-bevel off

You HAVE to go very light here and the stone needs a slurry or else you will form a burr again.

Then on the next stone, repeat the process.

On the final stone :

-do not grind at the edge angle, set the micro-bevel

This process should take 1-2 mins once you get it down, but it is very easy to over grind and the time will skyrocket up.

Remember the purpose of sharpening is to allow the knife to cut, you want to be minimizing time on the stones, so you are always thinking what is the least I can do



Edited 1 time(s). Last edit at 07/06/2020 02:33AM by CliffStamp.
Re: sigma 3k / 10k apexing difficulties of wear resistant steels
July 06, 2020 02:43AM
Cliff,
Awesome, thank you. I will play around with the stones and see what results I get. Do you think a stone like the King/Sun Tiger 220 SiC would be useful? A local store also has the Suehiro Chemical #800 325 grit stone, should I pick that up? Or try and track down a Naniwa SuperStone 400? I was going to pick up a Naniwa Aotoshi Green Brick of Joy, the store might have a SuperStone 400 also. If I use a coarse stone, it is the Task Garden hone. How does the Task, King 1k, and then a Spyderco M, F, or UF rod sound for apexing? I also have a DMT 1.2k, 8k, and the Venev OCB water stones, 800 and 1200 (FEPA) @ %100 abrasive content, and 1200 / 2000 (FEPA) @ %25 abrasive content.

"I am still discussing issues of steels and performance at this stage." -- Cliff Stamp, May his memory be a blessing
"Life is GOOD", -- Stefan_Wolf, May His Memory Be A Blessing
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Re: sigma 3k / 10k apexing difficulties of wear resistant steels
July 06, 2020 01:27PM
Jason,

I would recommend you simplify your sharpening, and try to minimize stones as much as possible keeping two broad ideas in mind :

-a friable, muddy stone is good for setting the edge with minimal burr

-a non-friable stone, is good for setting the apex

If you swap those, the opposite happens.

In general, there is little benefit to having a lot of close grits, like 120, 220, 325, 400, etc. , assuming your goal is to get knives sharp, and not just to spend time sharpening.

My stone setup is minimal ;

-a coarse stone for repair, changing edge angles; ideally very friable to minimize a burr

-a medium stone for regular sharpening, resetting the edge, ideally very friable to minimize a burr

This can also be used after the coarse stone, if the apex stone is too much of a jump in grit.

-an apex stone

Now I have a LOT of stones, because I like to play with them and different stones are ok for different steels, but if you can't get good results with two stones, adding more won't help, it will only make it worse as you are adding options/complexity into an existing setup which still isn't being optimized well.

Once you have the basics down, you can make things easier somewhat, for example something like :

-xx-coarse DMT to repair, but don't take it to the apex, just get close to it then switch to
-120 friable stone, to finish

This keeps the bevel mostly flat, and saves the constant flattening of the friable stone that will otherwise happen. But again, unless you can actually use the 120 stone to form that edge without over grinding and making a large burr, then you don't use those two stones because you just added a layer of complexity and there is just too much changing to try to figure out the problem if there is one.

If you want to get fancy, you can try to apex on friable stones, but you won't get the same kind of aggressive slicing finish on low grit friable stones anyway, and the technique is so much more involved, I just did it as I was curious if you could. See details in the above link on just how ridiculous you have to get to get decent sharpness.
Re: sigma 3k / 10k apexing difficulties of wear resistant steels
July 06, 2020 01:29PM
Cliff, speaking of minimizing time sharpening... Do you feel that lightly cutting off the apex into the stone as you’ve been known to do in the past is a worthwhile step when sharpening just a lightly dulled edge with no damage present?
cKc
Re: sigma 3k / 10k apexing difficulties of wear resistant steels
July 06, 2020 01:36PM
I have no experience with waterstones at all. i just don't use them, but I have heard that their behaviour is very different from what I'm used to, so I'm not going to comment on any of that, but I am going to offer a bit of feedback on some of the things that seem odd..

I'm sure some of these things we all do at times, but that doesn't mean they make sense.

There seemed to be a lot of randomness to your approach to the stone.
you would start and spend a lot of time with slow careful edge leading cuts, and then switch to fast inaccurate scrubbing strokes. and this also occurred all the way up the different stones.

scrubbing is rough, inaccurate and fast, and if you are going to do it, there is no point at all doing soft careful passes first. they will be destroyed by the scrubbing.

also not sure if there is a lot of point finishing with careful slow strokes on one stone, and then jumping to scrubbing on the next.

Now this next bit, I'm going to be highly critical. The reason being that many of your videos, I literally cannot actually tell if your knife is sharp, or what level of sharpness it is. This could be the technique you are using is misleading, or a number of other factors. so I'm going to describe what I'm seeing on video, and why I think its an issue.

when testing the tissue paper in EP 4 1:07, you are using a very fast lightweight sawing motion.. this is the polar opposite of the push cutting you express is your preferred testing and usage.
sawing light and fast like that, I would expect the knife to have gone through the entire tissue in a single draw slice off the first stone.
but I think in general this is not a good way to try and test sharpness as you can't tell if you have good draw cutting or good push cutting.
I think that you should be taking the test with a simple, single clear clean slice, and don't try to make it achieve more than it can.
i would not say it "slices paper towel" unless one single slow pass makes the cut.

@1:23 its slicing paper yes.. but I cant tell how well its slicing.. because it also looked like a very short cut in the paper, using the total length of the blade. this is my expectation of a dull knife, not a sharp knife. a sharp knife should require some draw (1cm max across a cut like that)

@1:29 you are saying its shaving, but I can't see it, video angle, quality, focus etc.. what I see is lots of tiny passes over the skin, and the skin looks very red after you move your hand as though the skin was scraped hard. but those tiny shot in place cuts at your arm are hard to see whats happening as it kills focus, and blurs things. again. if it can cut arm hair (not scrape, poke, pop) then this should be obvious from a single, slow clean pass that leaves camera in focus, and you see the hair fall off the arm.

I'm going to upload some examples I am making right now, as a point of example to what I mean.

here are 4 examples of kind of what i'd expect to see as a minimum for the type of test you showed.




----------------------------------------------------------------------
It's not Cliff, its Dr Stamp
#kebabstickcut, it's a thing - make it happen
cKc
Re: sigma 3k / 10k apexing difficulties of wear resistant steels
July 06, 2020 01:39PM
Quote
YESH
Cliff, speaking of minimizing time sharpening... Do you feel that lightly cutting off the apex into the stone as you’ve been known to do in the past is a worthwhile step when sharpening just a lightly dulled edge with no damage present?

Personally, I will never do this unless the knife is at the point where I feel that the sharpening is no longer responding. if you do this every time you touch up a knife, you are killing the life of the knife.

This is the sort of step to take IMO when resetting an edge, not when maintaining one.

a lightly dulled knife should be sharp in 15 seconds again.

----------------------------------------------------------------------
It's not Cliff, its Dr Stamp
#kebabstickcut, it's a thing - make it happen
Re: sigma 3k / 10k apexing difficulties of wear resistant steels
July 06, 2020 02:48PM
Quote
YESH
Do you feel that lightly cutting off the apex into the stone as you’ve been known to do in the past is a worthwhile step when sharpening just a lightly dulled edge with no damage present?

This is kind of an odd thing, as it is one of the few things that really caught on but people are often not doing what I intended. Often times I see people taking a barely used knife, grinding into the edge until it is severely dull and has a large flat, that was never the goal.

When a knife dulls, the very apex will be damaged, if you form a new apex on that steel you will have less than ideal edge retention and the sharpening process won't be ideal either. A lot of people will never notice this because they over grind all the time to large burrs, but if you sharpen to a minimum amount of passes (plateau sharpen) you will see it.

What I do is start with a very minimal pass into the stone unless the edge is heavily fatigued or chipped. On really cheap knives where I can see the edge is actually distorted, heavier passes might be necessary, no point in forming an apex there.

But what makes no sense is to take a knife out of a high grade PM steel which was barely used, is still shaving and do extremely heavy passes into an x-coarse stones as all you are doing then as Kyley noted is removing more metal than you would do with regular sharpening.
Re: sigma 3k / 10k apexing difficulties of wear resistant steels
July 06, 2020 03:44PM
cKc,
I was doing the slow passes because Cliff asked to see the reaction of the knife on the stone. Same with the paper slicing, Cliff asked to see the knife slice newsprint, I had phone book paper. I am having an issue still with my camera not filming more than 10 min, the scrubbing passes as so I get the knife sharp in a reasonable amount of time, since I was using fairly fine grits, and a fairly grind resistant steel. I apologize for the rest of the video, I am still trying to get a decent technique down, and I am not filming in my usual location. I didn't realize I barely had any arm hair left (or leg hair, for that matter) until I started sharpening, and went to shave, and what I did have was patchy. The first few times I tried shaving, it was scrape shaving, so that is why my skin on my arm was red.

"I am still discussing issues of steels and performance at this stage." -- Cliff Stamp, May his memory be a blessing
"Life is GOOD", -- Stefan_Wolf, May His Memory Be A Blessing
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Re: sigma 3k / 10k apexing difficulties of wear resistant steels
July 06, 2020 03:57PM
Cliff,
I am asking because I was wanting to know how those stones would fit into a sharpening method that includes your method. The method you came up with that uses the muddy stone and a hard stone to apex works so well, I rarely use it (unless I am having difficulties sharpening) because I like to play around with stones and sharpening. Mostly what I sharpen on now are just DMT plates and Spyderco Rods. I don't like to use waterstones unless I am going for a nice polish or I am having issues with a knife. This is because in my climate, they take three days to dry after use, and will become moldy if I don't dry them for that long.



As far as apexing on these stones, you can get a shaving sharp edge by using trailing passes after a few deburring passes, and the blade has to be sharp on the coarse stone. If you want a really sharp edge, a Spyderco Ceramic stone, diamond plate, or similar hard, flat stone.

"I am still discussing issues of steels and performance at this stage." -- Cliff Stamp, May his memory be a blessing
"Life is GOOD", -- Stefan_Wolf, May His Memory Be A Blessing
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cKc
Re: sigma 3k / 10k apexing difficulties of wear resistant steels
July 06, 2020 05:04PM
Quote
jasonstone20
cKc,
I am having an issue still with my camera not filming more than 10 min
...
I apologize for the rest of the video, I am still trying to get a decent technique down, and I am not filming in my usual location. I didn't realize I barely had any arm hair left (or leg hair, for that matter) until I started sharpening, and went to shave, and what I did have was patchy. The first few times I tried shaving, it was scrape shaving, so that is why my skin on my arm was red.

using a camera well certainly takes practice.. but that's it.. practice for 30 mins.

the goal of testing on shaving is to verify it can, not to try and force it to when it can't, so why are you "scrape" shaving at all? if you cant take hair off simply and easily, don't persist. just wasting precious resource of arm hair grinning smiley grinning smiley

this is a video I just did not on my partner's phone, which is basically the same tier as your phone, similar camera, and quality. but you don't need to try and take a lot of hair off if you don't have it. just a couple. the point is to focus on just taking hair off in 1 simple cut.
now on the phone its crystal clear,

just a small clean cut.. if it can't do this, why try to force it? back to the stone it goes.




this is the same video but this is uploaded low res, and its very hard to even see whats happening with fuzzy logic.
so its not just technique, and focus, but ensuring the video isn't downscaled during edit or upload




----------------------------------------------------------------------
It's not Cliff, its Dr Stamp
#kebabstickcut, it's a thing - make it happen
Re: sigma 3k / 10k apexing difficulties of wear resistant steels
July 06, 2020 05:37PM
cKc,
I understand what you are saying, and I appreciate the advice. The scrap shaves were not a display of sharpness, they were to test if the blade was shaving sharp or not. The phone was on a tri-pod, so I was trying to do a shaving cut on my right arm, which barely had any arm hair, cutting with my left hand. This isn't an easy thing for me to do, I have a hard time doing it when not on camera. Also, I can't hold the camera, hold the knife, and shave my arm hair at the same time. Most of the videos I did before were with my laptop, using a phone with a tripod is a different set of skills, which I have only done a few videos with. I don't practice filming, as I don't have the energy. If I have the energy to film, I film.

"I am still discussing issues of steels and performance at this stage." -- Cliff Stamp, May his memory be a blessing
"Life is GOOD", -- Stefan_Wolf, May His Memory Be A Blessing
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Re: sigma 3k / 10k apexing difficulties of wear resistant steels
July 06, 2020 06:56PM
As for how the stones fit in, right now I classify stones according to two very basic styles :

-they release grit and form a slurry, they are for setting the edge
-they don't release grit, they are for setting the apex

I normally use a two stone setup only more for the cases in the above. I have lots of stones, but that is for playing, not actual sharpening. Nothing wrong with playing with stones, I play with knives all the time as well.

Outside of that, the SiC stones tend to do better than the AO ones on the higher carbide steels, but that is a small secondary point, the first one still matters more. Trying to apex 10V on a SiC muddy stone for example is a nightmare.
Re: sigma 3k / 10k apexing difficulties of wear resistant steels
July 06, 2020 06:56PM
Cliff, Kyley(cKc),
I really appreciate your help.

"I am still discussing issues of steels and performance at this stage." -- Cliff Stamp, May his memory be a blessing
"Life is GOOD", -- Stefan_Wolf, May His Memory Be A Blessing
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Re: sigma 3k / 10k apexing difficulties of wear resistant steels
July 06, 2020 06:58PM
Cliff,
Would using a slurry stone to form a slurry on a stone work the same as using a muddy stone, or does it need to be the colloidal type of mud/slurry?

"I am still discussing issues of steels and performance at this stage." -- Cliff Stamp, May his memory be a blessing
"Life is GOOD", -- Stefan_Wolf, May His Memory Be A Blessing
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Re: sigma 3k / 10k apexing difficulties of wear resistant steels
July 06, 2020 07:55PM
I have been doing work by myself for the last few years, so I am not used to working with other people yet. It is awesome to share stuff and get good feedback.

"I am still discussing issues of steels and performance at this stage." -- Cliff Stamp, May his memory be a blessing
"Life is GOOD", -- Stefan_Wolf, May His Memory Be A Blessing
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cKc
Re: sigma 3k / 10k apexing difficulties of wear resistant steels
July 06, 2020 08:15PM
Quote
jasonstone20
I have been doing work by myself for the last few years, so I am not used to working with other people yet. It is awesome to share stuff and get good feedback.

I might have to get a cheap waterstone to see how they work one day..

other than that.. happy to help with the video work

----------------------------------------------------------------------
It's not Cliff, its Dr Stamp
#kebabstickcut, it's a thing - make it happen
Re: sigma 3k / 10k apexing difficulties of wear resistant steels
July 06, 2020 08:43PM
Quote
jasonstone20
Would using a slurry stone to form a slurry on a stone work the same as using a muddy stone, or does it need to be the colloidal type of mud/slurry?

This is an interesting question, and there is a lot of "it depends".

If you take an xx-coarse DMT, and make a slurry with a typical slurry stone, the slurry is very fine compared to the abrasive and while it will help, it will not be comparable to a 100 grit friable stone.

In short, you will get something similar to a friable stone IF :

-the loading stone is of similar grit
-you keep loading it during the cutting
Re: sigma 3k / 10k apexing difficulties of wear resistant steels
July 06, 2020 09:06PM
cKc,
I don't think you can go wrong with the King stones for something just to play with. The 220, 1k, and 6k (I haven't used this stone, but it has good reviews) King stones is a decent line up for less than $100 USD.

"I am still discussing issues of steels and performance at this stage." -- Cliff Stamp, May his memory be a blessing
"Life is GOOD", -- Stefan_Wolf, May His Memory Be A Blessing
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Re: sigma 3k / 10k apexing difficulties of wear resistant steels
July 06, 2020 09:09PM
In regards to shaving, if a knife does a push cut on light paper, it correlates very well to shaving. You just want a consistent very light paper, often a catalog will do it. I rarely shave, and if I do, I barely move the knife, it either does or it won't, either way, it happens immediately.
Re: sigma 3k / 10k apexing difficulties of wear resistant steels
July 06, 2020 11:50PM
Quote
CliffStamp
Quote
jasonstone20
Would using a slurry stone to form a slurry on a stone work the same as using a muddy stone, or does it need to be the colloidal type of mud/slurry?

This is an interesting question, and there is a lot of "it depends".

If you take an xx-coarse DMT, and make a slurry with a typical slurry stone, the slurry is very fine compared to the abrasive and while it will help, it will not be comparable to a 100 grit friable stone.

In short, you will get something similar to a friable stone IF :

-the loading stone is of similar grit
-you keep loading it during the cutting

Actually I just found these Naniwa Nagura Stones, they have a pretty solid grit range if anybody wanted to go this route...

[www.sharpeningsupplies.com]

My question in response, would be... what would the effect be of using a diamond plate to generate the slurry? I'd imagine the abrasive would get broken down a lot and it would be like using a much higher grit nagura.
Re: sigma 3k / 10k apexing difficulties of wear resistant steels
July 07, 2020 01:33AM
Interesting question. A higher grit diamond plate will likely cut the abrasive as well as grind it out, a coarse one will actually cut tracks in the stone making it much rougher. There are all kinds of interesting things you can do with slurry, if you have to use a stone and it isn't ideal.
Re: sigma 3k / 10k apexing difficulties of wear resistant steels
July 07, 2020 04:11AM
Cliff,
I was thinking of a stone like the Suehiro Chemical #800 325 grit, or the Sigma II Select stones? If I remember right, the Suehiro Chemical's slurry didn't do the shot peened grit pattern.

"I am still discussing issues of steels and performance at this stage." -- Cliff Stamp, May his memory be a blessing
"Life is GOOD", -- Stefan_Wolf, May His Memory Be A Blessing
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Re: sigma 3k / 10k apexing difficulties of wear resistant steels
July 07, 2020 07:52AM
Quote
YESH
Actually I just found these Naniwa Nagura Stones, they have a pretty solid grit range if anybody wanted to go this route...

[www.sharpeningsupplies.com]

If you have Naniwa SuperStones, the Naniwa nagura stones you linked to are identical in composition to the corresponding SuperStones. They work extremely well for allowing the stones to work across a much wider range of steel types and applied pressure if you match the nagura to the stone. I’ve been using the matched pair in both the 400 and 1,000 grits, I really like them.

I haven’t used them with any other stones, so I have no idea how that would work, but here’s an example of how I use the 1,000 grit pair to really broaden its usefulness:

The 1,000 is significantly more sensitive to steel types and pressures than the 400. It generally only provides that shot-peened and burr-reducing finish (which is what I want from the stone, either for setting the edge prior to applying a microbevel or for setting the edge on choppers, no microbevel, just straight off the SuperStone 1,000) if the steel type is very simple and not particularly hard (Svord 15N20, 420 class stainless, etc) and the edge bevel is less than about 0.100” wide.

If the steel is high-carbide or high hardness, or if the bevel is 0.125” or wider, it becomes extremely difficult to find the right amount of pressure to get the desired effect from the stone. Either the stone loads quickly and stops cutting, or it releases abrasive far too quickly and you waste the stone.

But if I constantly use the nagura to keep a slurry on the stone, I can use it on a much wider range of steels and bevel widths and still achieve the desired effect. I’ve done several direct comparisons where I use the same knives with and without the nagura and it’s very noticeable. A definite, observable, repeatable change in stone performance.



A quick aside about that SuperStone 1,000:

I’ve been very surprised at the level of sharpness it can produce when the surface is very muddy, full of swarf and abrasive. The 400 can get knives rough-shaving and slicing newspaper or similar fine papers, and the 1,000 is pretty much a direct refinement of the same. Much cleaner shaving, much cleaner cuts on the fine papers.

I would’ve thought it would be difficult to get decent sharpness when the stone is so full of lose abrasive and steel particles, but it’s really not that hard to do. It’s really nice for wood choppers or just generally getting high sharpness with maximum durability on other knives.
Re: sigma 3k / 10k apexing difficulties of wear resistant steels
July 07, 2020 01:36PM
Quote
jasonstone20
If I remember right, the Suehiro Chemical's slurry didn't do the shot peened grit pattern.

There are two types of slurries, generally :

-one which is much finer than the abrasive, and thick
-one which is mainly water and released abrasive

The first one is good for burr minimization, the second one likely best for cutting speed, but it will give a jagged finish, and will do little to prevent burr formation in over grinding. It does however reduce loading, keep the stone cutting fast.

I think the difference is in the nature of the bond, and I would guess that the first one is a mix of worn abrasive and binder, and the second one is a very porous stone with minimal binder that just releases bits of abrasive. But that is just a guess as to what is happening. The problem with stones is that often what we get are the off shoots of the industrial grinding abrasives so you get really odd behavior in stones :

[www.youtube.com]

Now the behavior of that stone makes no sense for a abrasive using in hand sharpening knives. It looks like it is an industrial abrasive which was designed to handle very high pressure/speed. If I was given that to sell I would return it because it is just nonsense. That stone has to be reconditioned constantly because it won't in use, and now you are forced with having to condition a 220 abrasive which isn't trivial. It should be designed (as is any abrasive) to break down in use and release worn grit. The problem is, the people selling these abrasives don't know even the basics of how abrasives operate and/or what they should be demanding for information to their customer base.

To be frank, right now we are in the era of sharpening stones similar to where we were in the 70's with steels where everyone was talking about the edge-packing in forging, and the super cutting ability of the katana, and "surgical stainless". There is just too much of a lack of information on stones, every time someone buys a stone they should ask/demand :

-abrasive (type and percentage)
-bond (type)
-structure (porosity)

Then with that information you can start making informed choices refuse to buy things from high end makers/manufacturers who are doing the equivalent of selling you mystery steels on high end knives.

Now if you buy a $5 stone, then you are buying a $5 knife so it is a mystery everything. But no one would buy a mystery steel knife from Spyderco with no details, so don't buy $100 to $200 stones with the same nonsense description.
Re: sigma 3k / 10k apexing difficulties of wear resistant steels
July 07, 2020 04:56PM
Quote
CliffStamp
To be frank, right now we are in the era of sharpening stones similar to where we were in the 70's with steels where everyone was talking about the edge-packing in forging, and the super cutting ability of the katana, and "surgical stainless". There is just too much of a lack of information on stones, every time someone buys a stone they should ask/demand :

-abrasive (type and percentage)
-bond (type)
-structure (porosity)

That’s what stopped me from buying several expensive Japanese stones I was interested in a few months ago. The descriptions were very vague, there was very little consistency in the few user reports I could even find, and the stones were all $80 to $120 a piece. It’s just too much to gamble on for me because I’m only interested in them from a utility perspective. If it didn’t do what I needed it to do then it’s just a $100 paperweight and I’d kick myself for blowing money on it.
Re: sigma 3k / 10k apexing difficulties of wear resistant steels
July 07, 2020 07:52PM
It is very likely the sellers don't know, just like all those dealers in the 80's and 90's . In was only in the 2000's when people really started talking about the details on line AND then they started demanding it that knife dealers were forced to provide details. Hopefully it doesn't take 40 years to change the information on stones like it did for knives.
Re: sigma 3k / 10k apexing difficulties of wear resistant steels
July 07, 2020 09:52PM
I think the biggest thing people can see when it comes to stones is... does it wear out quickly? When they see a stone that quickly hollows, yet cuts rapidly... they consider it junk. Because, they feel that there must be a superior stone out there that cuts just as quickly yet stays perfectly flat. These are of course at odds with each other, but they do not realize you cannot have it both ways and a stone that releases abrasive is often preferable to one that does not. That Beston 220 video you linked was painful to watch, I have used similar type of stones with similar results and it's just terrible performance.
Re: sigma 3k / 10k apexing difficulties of wear resistant steels
July 07, 2020 11:42PM
If you want a stone to not wear and keep cutting well, get a diamond or CBN plate and use it until the abrasive is worn and then get another one. Assuming you use it with lubricant and don't gouge it, for most people they are likely to last a lifetime anyway.
Re: sigma 3k / 10k apexing difficulties of wear resistant steels
July 08, 2020 12:52AM
The person using the 220 Grit stone in the video is the owner of CKTG, Mark Richmond (I believe that's his last name). I have dealt with him personally after having an issue with another stone, similar situation... coarse Nubatama 24 Grit waterstone with extreme bond that just glazed rapidly and asked for help with it. He actually offered me a discounted Atoma 140 to use in place of the stone, which I still have and use... though I feel it has been worn significantly as I've done some probably not so gentle things with it that are not recommended like changing geometries causing pressure spikes.

That said, he could not offer me anything in the way of an explanation of why the stone behaved that way... or even an idea how to fix it. He pointed me to Ken Schwartz, who I contacted and was told I needed to buy another stone of the same type to flatten and condition it (which I never did, still not sure that would work). So, as Cliff is saying the people selling these stones don't fully understand their properties or even what the best way is to use/maintain them. They did however, discontinue stocking at CKTG the stone I had after I called about it... so to his credit I think he was making sure that others did not have similar issues with them.
Re: sigma 3k / 10k apexing difficulties of wear resistant steels
July 08, 2020 01:13AM
Using the same stone to condition it would not help, that would just wear out both stones. You need an abrasive capable of cutting the stone which is more coarse than the stone.