Problem with Venev (OCB stone). Scratches too big?

nutsforknives · May 30, 2020

I have been using a Venev OCB 800/1200 and the 1200 produces a nice polish, but when I look closely there are little scratches all over the edge, keeping it from being a real mirror polish. I think there are diamonds coming loose, clumping and scratching the edge. Is there any way I can avoid this and get a clean finish? I have only used these stones on 3 knives and I am dressing them with an 8000 grit king nagura.

Old Biker · May 30, 2020

nutsforknives said:
I have been using a Venev OCB 800/1200 and the 1200 produces a nice polish, but when I look closely there are little scratches all over the edge, keeping it from being a real mirror polish. I think there are diamonds coming loose, clumping and scratching the edge. Is there any way I can avoid this and get a clean finish? I have only used these stones on 3 knives and I am dressing them with an 8000 grit king nagura.

I don't have a Venev OCB 1200, but it is a Fepa F grit rating. Which is the same rating as edge pro uses, So it would be the same grit as my edge pro 1200 and my Venev Gemini series 1200. Both give a hazy almost mirror finish. I'm wondering if perhaps, you are expecting a little to much polish from the stone. The edge pro stone is just their standard boride stone. The Venev Gemini series is metal bonded diamonds.

O.B.

Zeunerite · May 30, 2020

I have the B resin F1200/F2000 pocket stone. If I flatten it first with a 1000 grit diamond plate it'll produce a finish a bit finer than my 8000 DMT plate.

sickpuppy1 · May 30, 2020

Yeah. most stones will give as old biker said, a hazy shine, but not straight up mirror. Most of us going to a mirror will end up with stones up to 4K or so and them strop. So while yours are good stones and will give a great cutting edge they can only go so far.

nutsforknives · May 31, 2020

Old Biker said:
I don't have a Venev OCB 1200, but it is a Fepa F grit rating. Which is the same rating as edge pro uses, So it would be the same grit as my edge pro 1200 and my Venev Gemini series 1200. Both give a hazy almost mirror finish. I'm wondering if perhaps, you are expecting a little to much polish from the stone. The edge pro stone is just their standard boride stone. The Venev Gemini series is metal bonded diamonds.

O.B.

Its not so much that I am unhappy with the level of polish, because between the scattered scratches on the edge the level of polish is what I expect. I then strop on 1um and 0.5um diamond loaded strops to polish. It also isn't scratches left over from the previous grit, because it is clear that those are removed, and that would be on some parts of the edge and not others. It is a very consistent layer of small but clearly visible scratches that are much bigger than the scratches around them, which look right for a 1200/2.5um finish.

sickpuppy1 · May 31, 2020

I think I get what you mean now, most of it looks like you expect, but there are deeper scratches that are not consistent. Do you keep your stones clean and are you using leading edge strokes or edge trailing strokes. And very light strokes.. when going to that fine of diamond stone I am using trailing edge strokes and very light passes.

Diemaker · May 31, 2020

Without good photos we are just guessing but... I have seen this from stones where the abrasive is too fine for the bond and from microchipping with edge leading strokes. With microchipping the chip gets pulled between the stone and bevel scratching the bevel, the chip can embed in resin bond stones which requires them to be dressed to get rid of it. Then there are stones that are too fine to work with the steel being sharpened. I don't know what is causing the scratches but you can get to a point in the stone progression where the next finer stone leaves random deeper scratches. I know it is not contamination from my experiments, it just seems to be the limits of the bond. My solution is to move to a leather strop as it seems that the softer substrate for the abrasive is the way to avoid those scratches. My findings so far are Shapton Glass is good to 8k, the 16k is iffy and the 30k is useless. For the resin bond EP Matrix stones 5 micron is typically the finest diamond that works for most steels, 4 microns for Maxamet, and 2.5 microns on ceramic. In a comparison post I did are some photos of what I am talking about, Shapton Glass and Matrix. I have played with the older Venev 1200 and 2000 but not the new bond stones. The older ones definitely were not too fine in my experience.

wade7575 · May 31, 2020

Never use a diamond plate to flatten the Venev stones,you should 120 aluminum oxide powder and finish them with the same grit powder or 1 grit lower then the stone.

Are dressing the stones every time you use them because you shouldn't need to dress them at all,I never dress mine before use I only flatten mine.

wade7575 · May 31, 2020

nutsforknives said:
I have been using a Venev OCB 800/1200 and the 1200 produces a nice polish, but when I look closely there are little scratches all over the edge, keeping it from being a real mirror polish. I think there are diamonds coming loose, clumping and scratching the edge. Is there any way I can avoid this and get a clean finish? I have only used these stones on 3 knives and I am dressing them with an 8000 grit king nagura.

Diamonds are always going to leave more scratch's then a water stone,for example most people who have tried the Matrix and Venev stones will tell you that the Matrix stones give a more consistent scratch pattern and it's a bit more hazy then the Venev,the Venev give a bit polish but have a bit more inconsistent scratch pattern.

If you are wanting a trued mirror polish after using the Venev 1200 try a 4K water stone and progress as high as you want,you have to remember an 8K stone isn't removing hardly any metal and that's why it can't clean up the scratch's from the Venev stone,I have start with a 4K Chosera stone after the 1200 Venev and then went to 8 and 10K with great result's.

If you want a grit chart for converting FEPA rated stones such as the Venev stones I have a grit chart that's easy to use in pdf form and if you email me at wadenorton2008@yahoo.ca I'd be happy to email it to you.

nutsforknives · May 31, 2020

wade7575 said:
Diamonds are always going to leave more scratch's then a water stone,for example most people who have tried the Matrix and Venev stones will tell you that the Matrix stones give a more consistent scratch pattern and it's a bit more hazy then the Venev,the Venev give a bit polish but have a bit more inconsistent scratch pattern.

If you are wanting a trued mirror polish after using the Venev 1200 try a 4K water stone and progress as high as you want,you have to remember an 8K stone isn't removing hardly any metal and that's why it can't clean up the scratch's from the Venev stone,I have start with a 4K Chosera stone after the 1200 Venev and then went to 8 and 10K with great result's.

If you want a grit chart for converting FEPA rated stones such as the Venev stones I have a grit chart that's easy to use in pdf form and if you email me at wadenorton2008@yahoo.ca I'd be happy to email it to you.

Interesting. I have a Suehiro Rika 5k and 8k and I just started playing with the 8k in combination with the Venev. It seems after polishing on the Venev and 1um/0.5um strops, I get a really good apex but not very aggressive. If I take that edge and do 5-10 passes on the 8k waterstone it keeps its keen-ness but becomes way more aggressive, I think because I am exposing the carbides I just sharpened using the diamonds. Maybe I'll try doing it the other way around if I want a good polish, using the 5k/8k stones and then strop just the microbevel on diamonds to get it very fine, then maybe BACK to the waterstones to bring back the edge aggression! I'm mainly messing around because I'm under a stay at home order in California and I'm having fun learning about different combos of abrasive/grit/steel. So far I've yet to put an edge on s30v or m390 that rivals the edge on my Hitachi White#2 chef knife, but I'm getting closer.

wade7575 · May 31, 2020

When stropping you need to be careful that you don't use to much pressure because the leather can compress and wrap around the apex and round it off leaving you with a duller edge.
If you want Suehiro stones that are a bit faster cutting look at gritomatic and get the debado stones when they come back in stock,the cerax and rika are good stones but the debado cut a bit faster.

willc · May 31, 2020

wade7575 said:
When stropping you need to be careful that you don't use to much pressure because the leather can compress and wrap around the apex and round it off leaving you with a duller edge.
If you want Suehiro stones that are a bit faster cutting look at gritomatic and get the debado stones when they come back in stock,the cerax and rika are good stones but the debado cut a bit faster.

Are the Debado stones harder than the Rika?

nutsforknives · May 31, 2020

Diemaker said:
Without good photos we are just guessing but... I have seen this from stones where the abrasive is too fine for the bond and from microchipping with edge leading strokes. With microchipping the chip gets pulled between the stone and bevel scratching the bevel, the chip can embed in resin bond stones which requires them to be dressed to get rid of it. Then there are stones that are too fine to work with the steel being sharpened. I don't know what is causing the scratches but you can get to a point in the stone progression where the next finer stone leaves random deeper scratches. I know it is not contamination from my experiments, it just seems to be the limits of the bond. My solution is to move to a leather strop as it seems that the softer substrate for the abrasive is the way to avoid those scratches. My findings so far are Shapton Glass is good to 8k, the 16k is iffy and the 30k is useless. For the resin bond EP Matrix stones 5 micron is typically the finest diamond that works for most steels, 4 microns for Maxamet, and 2.5 microns on ceramic. In a comparison post I did are some photos of what I am talking about, Shapton Glass and Matrix. I have played with the older Venev 1200 and 2000 but not the new bond stones. The older ones definitely were not too fine in my experience.

You are describing my problem perfectly. Good to have an explanation for what I'm seeing. So far, I have only used an 8k nagura to remove load up from my venev stones. Do you think resurfacing the stone with something else would help? I also have rust erasers and a 1k nagura, but I don't have any lapping powders or plates or anything like that. I've heard a lot of people lap their venevs before using them?

Diemaker · May 31, 2020

I do not know how to dress a Venev. I tried loose 60 grit sic on a plate but don't feel it had any effect, but then I didn't think the stone needed dressing anyway. Again the only experience I have with Venev phenolic bond stones is the older ones.

wade7575 · Jun 1, 2020

willc said:
Are the Debado stones harder than the Rika?

I haven't tried the debado stones but a friend of mine who's not on this forum and lives in the states told me they cut faster,a harder stone doesn't mean that it will be a fast cutting stone,he has the Rika and Cerax bench stones for his straight razor and knives and said that the Debado is a faster cutting sone from he has found,I'm planning on getting a few Debado stones when they come back in stock.

Stones that are harder and more dense from what I have found tend to be slower cutting,stones that tend to create a slurry and release abrasive at a steady rate tend to cut faster because they are always revealing fresh sharp abrasive.

wade7575 · Jun 1, 2020

nutsforknives said:
You are describing my problem perfectly. Good to have an explanation for what I'm seeing. So far, I have only used an 8k nagura to remove load up from my venev stones. Do you think resurfacing the stone with something else would help? I also have rust erasers and a 1k nagura, but I don't have any lapping powders or plates or anything like that. I've heard a lot of people lap their venevs before using them?

It's not from chips that are embedded in the resin I have used the Venev stones for a very longtime and it's just the nature of those stones to leave scratch's behind.

What Venev stones do you have the 100% concentration or the 25%,the 25% are supposed to be more for polishing but they will not perform as good as a water stone.

You can try cleaning the swarf that builds up when sharpening but it doesn't help them cut any faster if your only sharpening 1 or 2 knives.

The best thing to clean most stones including the Venev's is to use Bar Keepers Friend Powder in the gold canister

nutsforknives · Jun 1, 2020

I have the 100% concentration. I can kinda see how a lower concentration might get around this issue a bit. I mostly got around it by using only stropping strokes on the 1200 grit, and rinsing the stone every now and then as I used it to clear away any diamonds that came loose and clumped up. The BKF is a good tip, thanks. I have some of that lying around

wade7575 · Jun 1, 2020

With the Venev OCB stones there's no problems with diamonds coming loose,it's just the nature of the beast and by that I mean diamonds and CBN in general are always going to leave scratch's.

If you want mirror polished edge's look on ebay and paste rainbow_sharpening_stones into the search bar and ask him to message you when he will have his debado stones cut and ask if he has any G8 stones,I know not to long ago he some G8 stone on ebay.

The G8 stone is my favorite Japanese whet stone by far,and any Suehiro stone I have ever purchased I have always been very happy with if you ask me I don't think they make any bad stones.

Zeunerite · Jun 2, 2020

wade7575 said:
Never use a diamond plate to flatten the Venev stones

Why not? My 1000 grit plate still works as well as it always did and my Venev stones no longer leave any deep scratches on my knives. I also use them dry and intentionally leave the swarf alone to let me know if I've reached the apex when it starts scooping up the shavings.

wade7575 · Jun 2, 2020

Zeunerite said:
Why not? My 1000 grit plate still works as well as it always did and my Venev stones no longer leave any deep scratches on my knives. I also use them dry and intentionally leave the swarf alone to let me know if I've reached the apex when it starts scooping up the shavings.

The reason for not using a diamond plate is very simple,you are going to have diamonds basically smashing into each other which will cause them to tear each other apart because they are the same hardness.

Also a diamond plate will leave deeper scratch's in the resin which is not good either because you have now just made it easier for the diamonds to be pulled out of the resin,from what Konstantin told me you should use an aluminum oxide powder that is 1 to 2 grit's lower then the stone your trying to flatten,I have also finished a F400 venev stone with F400 aluminum oxide powder with good result's,you can also use silicon carbide powder but it is more friable meaning a shatters easier and break's down into a finer powder faster and you'll end up using more.

Most people start with a F120 aluminum oxide powder then move onto a powders closer to the grit they want to finish at.

As far as cleaning the stones I'm only talking about cleaning them after you are done your sharpening session,if was going to sharpen 3 or 4 knives then I would clean them after the second knife just to unclog them a lot of people for some reason think you need to unclog them constantly while you sharpen which is not true at all.