Grit issues, does any one else see a problem here

I have been looking at a knife edge for about an hour getting frustrated and scratching my head. Tell me what you see when it comes to the scratch pattern. Note please forgive the poor pics. It's hard to take a pic through a eyepiece and hold a light at the same time. These are done at 100x. The grits are 8k and 16k.

16k
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8k
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Again in sorry for the poor pics. Tell me if you see a problem. The pics are not switched and the 16k was freshly flattened with a DMT325 and rinsed/cleaned off the best I could.

Forgot to mention both of these are Shapton GS

I assume your concern is that the 16k scratches are more dense than the 8k scratches. I guess without more photos and information, I'm not concerned.

Then again, they are not my hones or blades!

The greatest concern is the depth of the scratches and the 16k scratches SEEM deeper but it is hard to tell.

Yes I am concerned by the density of the scratches. Mainly that my edge is getting less polished on the 16k. I was thinking that if this is doing this on my knife what is it doing to my razor.

Well analysis of data is better than speculation. How about repeating this with a couple of razors?

How many strokes did you do on each hone?

In general you should not do many strokes on a 16k with a razor.

To get a better idea of what is going on, you may also want to change your honing direction between the 8k and the 16k, so that you can better see when the 8k scratches are gone. Make a crisscross pattern and stop when you can't see the 8k scratches anymore.
You will see more scratches per inch with a 16k than with an 8k because there is more grit per inch in the 16k than the 8k.
The 16k scratches should be narrower than the 8k scratches due to a smaller grit.
The 16k scratches should be shallower than the 8k scratches as well, but it is hard to judge the depth of cut in a picture.

Yeah it's hard to judge under the microscope too on the depth. Normally I don't look under my work microscope because the lighting is really hard to manage so I usually use a 45x lighted loupe. Under the loupe as I progress up the grits I always see a finer scratch patter with each grit level and almost a mirror reflection under the loupe at 8k until I get to the 16k. then the edge looks "scratchier" and less mirror like than the 8k. An so is my fear that my 16k is polishing less than the 8k. Because of this I decided to get the higher powered microscope out in hope to see what is going on.

And what's the difference between what the edges can do? I'm not one to look at pictures of scratch patterns, because that's not where the rubber meets the road. Having said that, that's probably why I can't really pull much meaningful information from pictures of scratch patterns...

The pics do not seem to be of the same area ?

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Originally Posted by onimaru55

The pics do not seem to be of the same area ?

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You are correct. I honed the entire edge to 16k then for half of the blade I went back in grit to the 8k so that I would have two samples of the same edge side by side to examine and compare.

Oh and before it's mentioned I examined the edge at 8k before moving to the 16k and the 8k was comparable to the above 8k. I just don't have any pics because I didn't think to snap a pic before I moved up to the 16k to see what it was doing.

I have heard of random particles breaking off stones & marring a finish. I have also heard the least likely stone that happens on is the Shapton GS.

Have you done this a number of times to prove it was not a one of ?

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Originally Posted by onimaru55

I have heard of random particles breaking off stones & marring a finish. I have also heard the least likely stone that happens on is the Shapton GS.

Have you done this a number of times to prove it was not a one of ?

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I'm going to be going through a testing phase and see if it's something I'm doing or if it is the stone (which I doubt, but can't rule it out yet). I'm been in contact since the start of my post with the guy at shapton and he's given me a few ideas to try. One of the reasons he gave me for my observation seems far out but I have to realize that he is the expert and in not.

Did I miss read ? You lapped a Shapton GS 16 with a DMT 325 ?

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Originally Posted by 10Pups

Did I miss read ? You lapped a Shapton GS 16 with a DMT 325 ?

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No you did not miss read. If there is a better option then I am ignorant to it. I used the DMT325 since the Shapton lapping plate is also 325. But if there is a better option than I will be glad to hear it. Always looking to better myself.

Please don't misinterpret my ignorance for a condescending question. I have since been to the Shapton site and looked around. I still haven't figured out all the numbering. But the shock of it for me was lapping a glass impregnated with diamonds with a metal plate impregnated with diamonds. My common sense (being right or wrong) had me wondering which plate would win that argument. My thought was " No wonder, the 325 diamonds are stuck to your 16k grit plate."

I'll just sit back and shut up now thanks :<0)

No misunderstanding here. I thought you happened to know of a better lapping option for the 16k. But the 16k along with there other glass stones is not diamond but rather synthetic ceramic bonded to glass plate. Now the lapping plate is a diamond plate bonded to a glass plate and is used only for flattening.

Now for the numbers. Instead of a grit size they go by the particle size in microns and have a mesh size that corresponds to there micron system. The mesh sizes is close to the JIS standard though it is slightly different

As said, if you are making comparisons, you have to compare the same area for the comparison to be valid.
And you are not honing to the edge…

It is not just about grit size…PRESSURE

Here is a great demonstration Same chalk… same Sidewalk… different amounts of pressure.


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Having seen it several times, that chalk photo is interesting but I'm not sure how valid it is. Chalk and steel are very dissimilar in mechanical properties, and while excess pressure can easily crumble chalk, it's not likely to cause steel to do the same. While hardened steel is certainly not what I'd call malleable, neither is it friable/crumbly like chalk. Now I think I'm going to have to do some scope photos with varying pressure to see exactly what the results look like.

Yes, dissimilar, but at the same time similar. The difference in PRESSURE causes the difference in depth of scratch pattern. With metal you need more pressure to get the same effect as seen on the chalk. It's not the material but the pressure as pointed in previous post. And that hold true in any field. We are always telling new shavers to watch your pressure, watch it on your strop to not dull the blade, watch it on your face to not get irritation, etc, etc, etc.

Oh certainly it's critical to lighten up on pressure when finish honing, but I'm not so sure it has to do with scratch depth so much as preventing the edge apex from being pushed away from the stone, and perhaps chipping on a microscopic level. I will do some testing and compare scratch depths soon, maybe start a new thread.

If not pressure how would you account for the OP’s issue, same razor half the grit size and same stria pattern?

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Originally Posted by Euclid440

As said, if you are making comparisons, you have to compare the same area for the comparison to be valid.
And you are not honing to the edge…

It is not just about grit size…PRESSURE

Here is a great demonstration Same chalk… same Sidewalk… different amounts of pressure.

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Thanks. I though I was watching my pressure, keeping the same pressure on the 16k as with the 8k. I'll keep a closer eye on it. But as with honing to the edge, I wasn't worried about getting to the edge as much as seeing what the 16k was doing. But I do agree with the chalk illustration and will try lighter pressure next time.

Plus this is a knife edge not a razor. But I was concerned about how my razor edges are doing on the same stone if I was noticing this on the knife.

I had a similar issue with the SG 16K and an Atoma 400. Got so frustrated with it that I called Shapton USA and they sent me a Shapton DG flattening plate to try out to see if it worked any better. Great plate, but similar issues. After several phone calls with Harrelson Stanley of Shapton USA who is an extremely knowledgeable and helpful fellow I found out:

The binder on the 16K and 30K is different from the other SG stones. That binder could be causing some of your issues. It can be made to work just fine though. Less pressure, clean water, no slurry, and less laps. I went so far as to "flatten" my 16k with my 8K to take out some of what looked like scratches, but to be honest i'm not sure that did anything. Try getting as good a finish on the 8k as you can, and then try the less is more approach.

Good luck and look forward to your results.

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Originally Posted by Euclid440

If not pressure how would you account for the OP’s issue, same razor half the grit size and same stria pattern?

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Well, I thought he said it was a knife first of all, but without being there and seeing exactly what he is doing I can't really do much accounting for it. My first thought would be perhaps those are 8k scratches and maybe he just wasn't hitting where he thought he was with the 16k. OP was this freehand sharpening?

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Originally Posted by eKretz

Well, I thought he said it was a knife first of all, but without being there and seeing exactly what he is doing I can't really do much accounting for it. My first thought would be perhaps those are 8k scratches and maybe he just wasn't hitting where he thought he was with the 16k. OP was this freehand sharpening?

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Yes this was freehand sharpening. But I just took the pics based on an experiment I was doing because I was noticing in spots where I had just finished on the 8k became scratchier after hitting it on the 16k. But I haven't had a chance to get out my 16k again yet, but I do think mjwit maybe on to something about the binder that I'm hoping to learn more about. Have to learn how to use my toys properly.

I had a similar issue with the SG 16K and an Atoma 400. Got so frustrated with it that I called Shapton USA and they sent me a Shapton DG flattening plate to try out to see if it worked any better. Great plate, but similar issues.

And… what happened?

You are talking about lapping a stone… it makes no difference. We lap a stone face to get the stone face flat. 400 grit is plenty small enough to produce a flat surface.

What counts is, how the stone performs on steel not what the stone face looks like. Finishing a stone face on an 8k would make no difference.

It is about the pressure. Many of us finish synthetic stones daily and have done so for years with a 325 grit diamond plate, on synthetic stones up to 30K.

It is not the stone…

Pressure… you are using too much pressure on your razor. At 16k you should be very lite pressure, to weight of the blade for finish honing.

Hmm, I have found that to be not entirely true personally. I have done a lot of experimenting and testing with varying lapped surfaces on my different stones, from very hard naturals to very soft synthetics. Hours upon hours of testing. On very soft stones it makes as near as no difference how they are lapped as they will quickly revert to their natural texture when used - often within a few laps on very soft stones. On medium to harder stones the surface texture can make a significant difference to the way the stone cuts and the finish it imparts. The difference on something like a Shapton (medium hardness) stone when being lapped with a brand new 325 grit diamond plate vs. with a well-worn 325 grit diamond plate is quite significant. In point of fact, if the OP is lapping these two stones with a brand new or not very worn 325 diamond plate I'd say that would explain the issues he is having right there if honing with light pressure. He should lap the stones then rub them together until they are smoothed, (most of the scratches from the 325 are gone) and I think he will see a difference in finish immediately.

Guess we’ve all been doing it wrong…. OMG


It’s not the stone…

So first we are talking about Synthetic stones, and second he is lapping with a 400 Atoma and a Shapton Lapping plate, both of which produced the same results…

What cuts the steel, the top of the grit… or the bottom of the land made by the lapping plate grit?
The STEEL razor will ride on top of the grit… unless the user is using too much pressure.

Besides, this is a 16K stone, where he should be using weight of the blade pressure to finish hone anyway.

It is not the stone or the lapping plate… as he proved to himself.

This user and the OP are simply using too much pressure… just like the chalk photos clearly demonstrate.

The low point of the groove doesn't do the cutting, that's correct, and no one is arguing that point. But to say that the surface prep makes NO difference is not correct in my experience unless you are talking about a very soft stone. The difference between diamond plate grits isn't so much the significant factor, it's the freshness of the plates and sharpness of the diamonds that makes more difference. This difference shows up both in finish and cutting speed. The difference is in the amount of stone in contact with the steel, and how those contact points are shaped. The reason light pressure is important I think is that it gives uniform repeatable contact with the stone. Heavy pressure means any change in pressure results in a contact point shift, which makes it more difficult to finish an edge. It can also be important for some razors as heavy pressure on certain razors can result in chipping on a microscopic level.

Here are two photos at 200x taken with raking light to emphasize scratch depth. Both the same razor in the same place on the blade. One was honed with weight of the blade, one with about 10 pounds of pressure measured on a postal scale. About the same number of laps for each. Do the scratch depths look significantly different? FYI I just shaved with the heavy pressure edge with no ill results. It shaves pretty much the same as the light pressure edge - maybe not quite as smooth ATG, but indiscernible WTG.

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Here are 2 more shots showing the same razor, same edge. One is the result of a stone lapped smooth with a finer synth stone, and one was lapped on 80 grit wet/dry. Look at the drastic difference near the edge. Both honed with weight of the blade level pressure.

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P.S. all these shots are honed on the same stone - a Shapton Pro 8k.

What is the stone you are using?

The poster was using a 16K Shapton stone.

That stria and edge look much more course and we are not talking about 80 grit to lap we are talking about 400 grit.

Most of us use a 325 DMT and it works just fine.

I have been using a 300 grit I Wood plate lately and it works even better than my old DMT. Lapped a 20k Guyokomo with it new and it is producing very nice finished edges, I shave comfortably off the stone.

Some .125 CBN does improve it a bit more.

Sorry guys, even though it may not be that big a deal, I use a 325 DMT, not a Atoma 400.

Well I guess we can all agree 80 grit wetndri is not a good lapping medium for finishing stones.

Yea, the guy that kicked this off, was mjwit, who lapped a 16K Shapton with a 400 Atoma.

It does not really matter as synthetics can be lapped with any thing from a 300 up to 1200 Diamond Plates, with about the same results, though clearly lower grits will be much faster than higher grits.

Ahhh, yes I see now. Sorry got a little confused about who u were talking about and when. Now I see. Never mind my ignorance. Oh and before I forget thanks guys this discussion really has helped me a lot when it comes to understanding my technique and stones better.

As noted in the post, all edges shown are finished on an 8k Shapton Pro. The 80 grit wet/dry obviously is not optimal, that's the point I'm trying to make. I just don't have a new diamond plate to demonstrate, so had to make do with what I had available. A new diamond plate of any grit lower than 800 is WORSE than the 80 grit wet/dry. Once they break in a 325 is fine. Even a DMT XXC is fine. Look back and see what I said - if the 8k/16k guy is using a new, not well-worn diamond plate, that could explain the whole issue. (He did say he was sent a brand new DGLP to try, which is definitely going to produce a coarser finish vs. a more worn plate ). The sharp diamonds really do produce a bad finish, as well as allow pieces of stone to break away and act as slurry. The net result is a coarser finish and a very rough feeling edge.

The fewer laps you do with a coarser lapped stone the worse the finish will be. More laps lets the stone revert closer to its natural texture, as I stated earlier.

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Originally Posted by eKretz

The fewer laps you do with a coarser lapped stone the worse the finish will be. More laps lets the stone revert closer to its natural texture, as I stated earlier.

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So what would be our remedy to help us get to that natural texture? Would we lap until flat and then lap some more allowing the slurry produced to "grind" away the rough surface level of the stone and only leave the smoother natural texture that we are looking for?

More laps! Or break the diamond stone in a bit by going at it on a chisel or something like an Arkansas stone for a short while. Once the diamond plate is broken in a bit the diamonds get slightly rounded or flattened, and at that point the coarseness of the diamond plate makes much less difference to the imparted finish, (though still affects it a bit) but will still affect the cutting speed/aggressiveness a decent amount. (Coarser diamond plate lap will get the stone to cut faster).

Here are a few more shots from my testing. Only concentrate on the finish nearer the edge. You can see that the scratches are fewer and shallower as the lapping gets finer even with worn diamond plates, but not nearly as significant as it would be with a new plate.

Well-worn DMT XXC lapped stone:
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Well-worn Atoma 140 lapped stone:
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Well-worn Atoma 400 lapped stone:
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High-grit synth lapped stone:
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Here are shots of the actual lapped stone surface showing surface texture with the different lapping coarsenesses.

80 Grit SiC:
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Very Worn DMT XXC:
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Worn Atoma 140:
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Worn Atoma 400:
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High grit Synth:
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This last is interesting because you can see that the softer synth stone wears the binder away faster than the abrasive particles, leaving them slightly proud of the binder, whereas the diamond lapping levels the entire surface of the stone evenly.

Also note the difference between the DMT XXC and Atoma 140 - both in the stone surface texture and in the bevel/scratch pattern near the edge. Even though the DMT is a coarser plate, mine is so worn that it produces a finer finish on both the stone surface and the imparted finish on the razor.

You're using unrealistic examples for lapping plates. Nobody uses 80 grit wetndry for a final finish on a stone, same as a 140 grit Atoma. Well actually I use a 140 grit Atoma but only on 220-320grit stone.

I believe the op did not use an Atoma so that's really another discussion.

The op's problem is possibly one of pressure when honing, tho why would he use more pressure on 16k over 8k ?

Or the 16k stone could be faulty. If he has lapped both the 8k & the 16k with the same plate it is fair to assume the 8k should show a coarser finish.