Microchipping on Naniwa ss8k

[Edo]

hello everyone.

I need your help.
I'm having problems with the Naniwa Super Stone 8K. Long story short, it destroys my edge.
The stone was lapped, cleaned, tested with its nagura (8k), tested with clean water, and with different razors each one with angles above 17 degree.
Always the same result. Microchipping everywhere, no matter how little or how light hand I stay on the hone.

I have been sharpening successfully for quite some time. I’m sure the bevel is impeccable, uniform bevel that passes all tests. I can shave nice directly from 1k and leather strop.
My progression is 1k chosera; 3k chosera; 5k chosera. I attach a photo of the result of 10 light laps on the naniwa, used with clear water.
Previously the edge was perfectly straightened. No burr, no foil.

Thanks to anyone who wants to advise me

 

[psfred]

Looks like random coarse grit, either in the stone itself or stuck to it from lapping. Some high grit stones are fairly soft and grit will embed in them easily, so contamination from a coarse stone on your lapping plate will get stuck in the surface.

If it were mine, I'd flatten it on a clean plate of some sort then wash well, scrub with a Mr Clean magic eraser, and then work the surface with something like a coticule, some hard, fine stone that won't shed junk. After that I'd I'd test with a junk razor or chisel or something, not my good razors! I'd NOT use a coarser stone to flatten it.

If you still have problems then, I'd suspect coarse grit contamination in the stone itself. Highly unusual for Naniwa, but stuff does happen.

 

[Edo]

Looks like random coarse grit, either in the stone itself or stuck to it from lapping. Some high grit stones are fairly soft and grit will embed in them easily, so contamination from a coarse stone on your lapping plate will get stuck in the surface.

If it were mine, I'd flatten it on a clean plate of some sort then wash well, scrub with a Mr Clean magic eraser, and then work the surface with something like a coticule, some hard, fine stone that won't shed junk. After that I'd I'd test with a junk razor or chisel or something, not my good razors! I'd NOT use a coarser stone to flatten it.

If you still have problems then, I'd suspect coarse grit contamination in the stone itself. Highly unusual for Naniwa, but stuff does happen.

Thanks! Tomorrow I'll try to do as you say. I will post the results. First time something like this happens to me. Thanks again

 

[Darth Scandalous]

Might try lapping the back side and testing that separately.

 

[Gamma]

Can't say what is causing your exact issue, or issues, since I am not there to witness the process. The image alone doesn't provide enough information. FWIW, by the photo, the previous work does not seem to be 'impeccable'.

Nani Super Stones sometimes have a less than stellar honing surface to work with. I have had two 12k SS that needed a LOT of material lapped off. With a 4x loupe I could see major differences in the stone's makeup and texture.

Honing razors on synths above 2-3k, with slurry, can cause chipping, rogue striations, edge failure and set back.

In that photo I see a lot of random striations that seem to be deeper than they should be. I also see striations going in myriad directions. The two combined can cause micro shipping. Looks sorta like 1/2 strokes and x strokes with different angles were used. Consistency matters.

Some, not all of, the typical culprits of honing issues, chipping, etc.

Uneven stones, check flatness with a quality straight edge.
Super Stones are known to warp.

Dried out top, or out of spec stone. It happens.

Too many laps, really shouldn't need more than 20-25 laps on an 8k.. Endless honing can bring issues to the apex.

Too much pressure - should be finishing, not grinding.

Stone loaded with swarf. When I hone, seeing heavy swarf from the first strokes on an 8k means the previous work wasn't done correctly. Light trace swarf is acceptable. Trying to hone on embedded swarf makes for a bad experience.

Too much pressure on 3k, 5k, leaving rogue striations, gouges, and areas prone to chipping. Remember edge width is approx .4 µm, it is fairly delicate. A rogue scratch from a 3k stone, 4µm, can wreak havoc pretty easily.

Don't overlook steel failure. I don't know the status of the blade in the photo but a lot of ebay specials have a lot of rotten steel baked into them and it all needs to be honed out before a stable and consistent edge can be established.

 

[Edo]

Thanks! I'll check it out point by point. I will post the results. Next time with a picture of every step.

 

[Edo]

Can't say what is causing your exact issue, or issues, since I am not there to witness the process. The image alone doesn't provide enough information. FWIW, by the photo, the previous work does not seem to be 'impeccable'.

Nani Super Stones sometimes have a less than stellar honing surface to work with. I have had two 12k SS that needed a LOT of material lapped off. With a 4x loupe I could see major differences in the stone's makeup and texture.

Honing razors on synths above 2-3k, with slurry, can cause chipping, rogue striations, edge failure and set back.

In that photo I see a lot of random striations that seem to be deeper than they should be. I also see striations going in myriad directions. The two combined can cause micro shipping. Looks sorta like 1/2 strokes and x strokes with different angles were used. Consistency matters.

Some, not all of, the typical culprits of honing issues, chipping, etc.

Uneven stones, check flatness with a quality straight edge.
Super Stones are known to warp.

Dried out top, or out of spec stone. It happens.

Too many laps, really shouldn't need more than 20-25 laps on an 8k.. Endless honing can bring issues to the apex.

Too much pressure - should be finishing, not grinding.

Stone loaded with swarf. When I hone, seeing heavy swarf from the first strokes on an 8k means the previous work wasn't done correctly. Light trace swarf is acceptable. Trying to hone on embedded swarf makes for a bad experience.

Too much pressure on 3k, 5k, leaving rogue striations, gouges, and areas prone to chipping. Remember edge width is approx .4 µm, it is fairly delicate. A rogue scratch from a 3k stone, 4µm, can wreak havoc pretty easily.

Don't overlook steel failure. I don't know the status of the blade in the photo but a lot of ebay specials have a lot of rotten steel baked into them and it all needs to be honed out before a stable and consistent edge can be established.

I couldn't wait until tomorrow to try.

I did everything you kindly suggested: lapped stone with atoma 600; controlled; cleaned with bout of yellow Belgian; rinsed. I took a test razor, a gold dollar (the bevel is very, very high, but the geometry is good and I had already used it before, so I know it).
I started from 1k.
I did a couple of sets of about fifteen circles, with light pressure, then 50 laps, decreasing pressure.

All checks passed for me.
3k, x stroke only, 50 laps, light pressure to reduce.

5k, x stroke only, 30 laps, blade weight only.

8k (the cursed one ), x stroke only, 10 lap, blade weight only.

Little to no swarf on the stone, nice adhesion. all stones used only in clean water, always hydrated.

 

[JPO]

I couldn't wait until tomorrow to try.

I did everything you kindly suggested: lapped stone with atoma 600; controlled; cleaned with bout of yellow Belgian; rinsed. I took a test razor, a gold dollar (the bevel is very, very high, but the geometry is good and I had already used it before, so I know it).
I started from 1k.
I did a couple of sets of about fifteen circles, with light pressure, then 50 laps, decreasing pressure.
View attachment 1908044
All checks passed for me.
3k, x stroke only, 50 laps, light pressure to reduce.
View attachment 1908045
5k, x stroke only, 30 laps, blade weight only.
View attachment 1908046
8k (the cursed one ), x stroke only, 10 lap, blade weight only.
View attachment 1908047
Little to no swarf on the stone, nice adhesion. all stones used only in clean water, always hydrated.

I have the same 8k stone.
These are not soaking stones. However, my stone gets bone dry, and tend to soak in some water.
In this state it's terrible to use. It feels like honing on a wet sticky eraser.

The solution for me was to soak it for 5 minutes, and lap the surface.
You need a fresh surface.
If you start to get resistance on the razor you will end up where you are now if you just pull through.
5 to 10 strokes is usually enough for me.

 

[Edo]

I have the same 8k stone.
These are not soaking stones. However, my stone gets bone dry, and tend to soak in some water.
In this state it's terrible to use. It feels like honing on a wet sticky eraser.

The solution for me was to soak it for 5 minutes, and lap the surface.
You need a fresh surface.
If you start to get resistance on the razor you will end up where you are now if you just pull through.
5 to 10 strokes is usually enough for me.

Thanks!

I've never tried soaking it. I noticed the same things as you. I always limited myself to spraying it often with water.

I will definitely try as you say.

 

[Gamma]

@Edo

Generally speaking, I recommend not using natural stones to clear or smooth synthetics. Particularly Coticules.
IN the past I was using a BBW to polish synths but then I found that the stone's slurry was embedding into the soft synth binder. My SS and Chosera were literally bleeding out purple slurry when drying after lapping/polishing. Had the same issue with Coticules, the synths were leaking out pasty white/grey Coticule slurry.

Not saying this is the root of your issue, and I am so sure that someone is going to say they've been doing it for years without issue. Good for them. Factually though, Coti and BBW slurry can get 'into' the stone. Same for SIC powders and any other loose abrasive. I use a worn 400x Atoma to lap, or a 140x when heavier work needs to be done. Doesn't need buffing after that, just a rinse and light rubbing with my fingers to check the surface smoothness.
I don't find the 600x or 1000x Atomas to do as well for lapping, I'm convinced that the diamonds are much less durable.

Many critically aware honers don't use circles because doing so leaves messy looking striation patterns. One content creator showed off how doing circles on his coticule was causing damage to the apex. I'll use circles for heavy work sometimes but pass on it for 1k-finish usually.

Lapping is one thing, checking for flatness is another. Lapping off grids does not mean the stone is flat. With a SS, flat now might not be flat later. A SS that warps will be hellish if you soak it. A dunk is fine but soaking, in general, not good for that particular binder. Edges chamfered and smoothed off too.

Microscope images are limiting because they don't impart understanding. I don't use imagery to hone, never did. I have a scope but I never used to learn how to hone. People love seeing the high mag photos but they only show a micro fraction of someone else's story. You only see a miniscule part of a result, not how it got there - which is more important.

That said,
By looks @ 8k, I see deep striations leading to the majority of the chips.
By looks, @ 5k I see much of the 1k and 3k work still present. The deeper scratches are similar to what I see @ 8k.
By looks, @ 1k the striations look to contain original GD grind marks, or maybe the blade was on a diamond plate at some point.
I think GDs are set up on a belt sander originally, very difficult to remove 100% of that noise.

But looks can be deceiving and/or misleading.
You may have a stone with rogue particles, the gouges leading to the chips could possibly be from the 8k.
But they might be early work rearing it's ugly head. Can't say.
You possibly may have a technique issue.
Could be a combo of things.

Over the years, I have found most similar scenarios to be the result of, like 99% of the time, user-error.

But more than once in a while the user is an innocent bystander in a cruel joke played by Mother Nature or a stone manufacturer.
I mentioned before that Nani Super Stones have had issues. Chipping blades has not been a common issue but anything is possible. Honestly, if your 8k was the absolute sole root cause of that chipping, I'd expect you to be able to feel it happening when honing. The striations leading to failure are very significant, it would be like feeling 1k grit in an 8k stone.

A lot of time, people run into chipping because they are polishing without enough healing. It's one reason I stress mid-range work and constantly remind people that bevel-set is a process and not an event. I spend a LOT of time at 3k and 4k/5k. Counting laps is irrelevant, the bevel is done when it's done.

Way back long ago, while honing I used to wipe the blade down with a cotton towel, I had much chipping.
Turns out that mini fibers from the towel were causing the edge to chip in places where the honing wasn't spot-on.
Lots of things can happen and cause these headaches.

 

[JPO]

Thanks!

I've never tried soaking it. I noticed the same things as you. I always limited myself to spraying it often with water.

I will definitely try as you say.

Was this a Gold Dollar?
Some of these will start to release bits off the edge at a certain refinement level, which might imbed into the stone.
Using slurry can also set you up for failure late in the game.

 

[Edo]

Thanks so much Gamma,

this was the kind of response I was hoping for. lots of food for thought. I will try to put these tips into practice. I will definitely do more tests with this stone in the next few days and will let you know.

p.s. I also never use the microscope, I took it out on this occasion precisely because, as you say, I felt something wrong was happening with the 8k.
I usually don't count passes and I agree with you on the relevance of medium grit. here I wanted to count and stay a little less, to highlight that I didn't spend too much time on the stones.
really valuable advice, thanks again

 

[Edo]

Was this a Gold Dollar?
Some of these will start to release bits off the edge at a certain refinement level, which might imbed into the stone.
Using slurry can also set you up for failure late in the game.

Yes, it was. I will clean the stone, I will put into practice the advice given to me, and I will do some other tests with a good razor

 

[JPO]

Yes, it was. I will clean the stone, I will put into practice the advice given to me, and I will do some other tests with a good razor

The gold dollar is really not a usefull tool to use if you are trying to get to the bottom of this. It might also just be the razor.
Use them to open mail that contains good vintage razors

 

[Edo]

I totally agree, but as I said at the beginning, the problem on this stone occurs with various razors. I used the gold dollar today just to show the point.

 

[JPO]

I totally agree, but as I said at the beginning, the problem on this stone occurs with various razors. I used the gold dollar today just to show the point.

I am not suggesting you get a new stone.
However, a stone like the Naniwa snow white wil probably give you a different experience.
My Naniwa ss 8k is gathering dust.

It does create a nice polish though.

 

[Edo]

JPO

I also have a naniwa gouken fuji 8k. Totally different story the Snow white miss in my collection.

 

[Gamma]

I usually don't count passes and I agree with you on the relevance of medium grit. here I wanted to count and stay a little less, to highlight that I didn't spend too much time on the stones.

Its the finer grits where too much time/effort/passes/etc causes issues.

From bevel-set to that point, the steel has to be healed, nearly perfectly, for the apex to maintain it's integrity.
If not, then the deep striations will cause failures, leaving gaps in the edge. Chips. I think the 3k and 5k images show a lot of room for a lot more work to be done. The original images 'proving' that the Shapton Glass 16k chipped edges were based on improperly done ground work and too much time on the Shapton 16k. Was a farce but it convinced many that the stone was bad when it was actually intentional user-error.

The striations leading to the chips in the 8k images are very deep. There are no 8k particles making those ravines. Looks like 1k striations, or coarser. Maybe the 8k stone is infected with coarse grit from the factory or from something done afterwards. I would do a lot to ensure there is no contamination. I would check all stones for this actually.

It could be possible the binder is clumping, but the results would look differently, usually.

If you want to get more out of the images, then put a witness mark on the blade and put it in the same place in the frame every time so it is possible to track things better. Taking random images from different sections of the blade across the process can lead to false conclusions.

What were you using to finish razors on before you got the 8k SS?

 

[Edo]

work permitting, tomorrow I will mark the bevel and post photos of the same point. I will also improve the work of the 3k and 5k. I have many different stones. I usually go from 5k pro to 10k pro. Lately I've been using an Arkansas progression, soft-hard- translucent. good shaving results. smooth against the grain, non-stinging alcoholic aftershave. I also have experience with some jnat

 

[H Brad Boonshaft]

So first try to photograph the same spot each time so you can easily compare where and how stria pattern and edge are refined. Mark a sharpie line from edge to back of the bevel for registration or pick out a defect on the bevel or belly.

Your honing looks good, nice pics and even stria pattern up to 5k where there is some deeper stria on the left but don’t know of that was prior to 5k.

There is an issue with your Super Stone, but they are problematic stone, fussy finishers and fussy with water control. Don’t soak but do try a squirt bottle in place of a spray bottle to keep the stone face flooded and as swarf free as possible.

If you allow black swarf to build it will scratch the bevel and chip the edge. Clean the stone face with a Magic Eraser at slightest build up and give it a fresh lap with a 4-600 plate before you finish laps.

Also check that your stones edges are beveled or rounded and not sharp as dragging over them can scratch.

I also noticed with Super Stones if let sit un-used and un- lapped for a while, they build up a tough “skin” that will affect performance. A grid marking and through lapping with a 140 plate will cut through and refresh the stone face. You may need to grid lap the stone 2-3 times.

The Fuji and Snow White are much better performers.