My apologies - a Norton 8000 question

Re: My apologies - a Norton 8000 question

Kurt Loup, Baton Rouge

>Sounds like my first experience with the Lee Valley 8000 grit stone. I was getting a better polish off of the Shapton 5000 pro stone. Further investigation revealed the problem. The stone wasn't close to being flat out of the box. After flattening with 600 grit silicon carbide grit on a lapping plate, it worked much better.

Kurt

Re: My apologies - a Norton 8000 question

John Kissel

>Hi,

A few thoughts on this (don't have an 8000 Norton or anything higher than 6000 myself)... First would be how does your actual edge compare b/w the 8000 and what you used to get w/ SS? Some of the natural waterstones in the finer grits will leave a matte finish with a very sharp edge. Some folks prefer it to the shiny finish. The variable bands sound like it could be related to the flatness of the stone as was mentioned or possibly in how the pressure is applied while flattening.

JK

It might have been....

Dave (Arlington, VA)

>because of an earlier post of yours, Kurt, (or someone elses) that when I started using my stones, the very first thing I did was to flatten them (out of the box) on an appropriate grit sandpaper.

So, when I pulled out this 8000 stone, I promptly took it over the table where I keep my 3/8 piece of glass and flattened it on 600 grit W/D sandpaper.

I also reflattened it periodically between each session of flattening/polishing on each of the two blades.

That's not to say, for sure, that I'm getting the stone flat - but when the pencil grid marks I draw on its face are gone/erased/abraded away, I consider it flattened.

Kurt, thanks for your post.

Dave

Re: It might have been....

Ted Shuck

>Dave,

Do you think you might have left any of the 600 grit particles embedded in the waterstone after flattening? These remnant particles could be making your waterstone a coarser grit than you want.

Ted

I often wonder...

Ryan Stagg -- Cincinnati

>...about that, Ted. I'm a neophyte waterstone guy, and always wonder if I'm contaminating the finer grits with the coarser ones, like the 4000->8000 jump on the Nortons. Is there a preferred way to avoid this, with both flattening and progressive sharpening? Dip the stones/blades in water before progressing?

Dave -- I've also seen this 'banding'. On mine, it's clearly honing the full face, but the top half (the non-edge half) of the face looks 'duller' somehow, almost the same look as a laminated Japanese blade.

Re: My apologies - a Norton 8000 question

Wiley Horne--Glendora CA

>Hi Dave,

Well, stone contamination could be the problem, as Ted suggested.

One other possibility is the one I experienced some time ago. You can get the effect you describe if there are residual scratches from coarser stones still in the blade when you get to the 8000. Sometimes these coarser scratches can get masked over by medium grit stones, but then reappear. In my experience, the harder the steel, the more likely this is to happen. Your observation about alternating-murky-with-bright in the inch above the edge makes me think this is what is happening.

A couple of diagnostics. Take a 5X or 10X loupe and examine the blade carefully for coarse scratches lurking underneath the polish. There is a scratch pattern which is producing the murkiness--you're trying to decipher what it is. If you see a combination of coarse scratches underneath very fine 8000 scratches, then that would confirm you need to go back to whatever will remove the coarse scratches. However, if the scratches (at the blade edge) seem fairly uniform or hard to decipher, this might argue for stone contamination. In that case, I think I would check whether 2000 automotive paper will brighten the edge, and look at those scratches. Then go carefully clean the 8000 stone, repolish the blade edge and look at those scratches. These tests will tell you what is happening. But there's no black magic about interactions between certain stones and certain steels causing this kind of problem--it's all about scratches.

Wiley

Re: My apologies - a Norton 8000 question

Lyn J. Mangiameli

>I haven't used a Norton 8000, but I have used the LV King 8000 and the Shapton 8000, as well as the Shapton 12000. Perhaps some of my experience will generalize.

I find a lot of difference in reflectiveness between the fine stones, and whether they are used wet or dry. I also find a lot of difference, like you, between abrasive "papers" and the abrasive "stones." Personally, I think it is due to two things, but I don't have any scientific evidence for this.

First I think it has to do with particle size and shape. Abrasive papers are easily available with particle sizes smaller than an 8000 waterstone. With Scary Sharp, I go down to .5 or .3 micron (the latter thanks to Russell). To get a comparable size in a waterstone would require a stone in the 20,000 range. Thus while an 8000 edge is usually great, it is not as refined as some might expect, when compared to the finely graded abrasive papers or diamond slurries.

The second thing is more an optical issue. Reflection is increased when the scratches are small,consistent in size, well defined and directionally uniform. Most think of the first two, but not the well defined and directionally uniform. What I mean by well defined is that the scratches themselves are "sharp". This comes from an abrasive particle that has clear angular fractures. Diamonds are pretty good at this, but most other abrasives quickly wear and their cutting edges become rounded. The rounded edge abrasives dig U shaped troughs, rather than cut V shaped grooves. The V shape will reflect more light because the light is bouncing off something closer to a flat plane.

While all abrasives will become rounded with extended use. I believe the slurry that forms with a waterstone rounds particles faster than those abrasives held in place by a binder (being it the surface of a waterstone used dry, or an abrasive paper).It just the tumbling effect of all those particles of similar hardness left free to bang against each other. The resultant particles may become smaller, and leave smaller scratches, but they won't leave the V shaped grooves conducive to reflecting light.

Rolling particles also are going to result in less uniform scratch patterns. The fixed (including embedded) abrasives will leave linearly aligned scratches if one moves the blade over them in a single direction. Free particles will "wobble" as they cut, leaving a serpentine rather than linear scratch. The difference is subtle, but make all the difference optically. With the former, the light is reflected coherently, with the latter, the light is slightly scattered. With respect to achieving a refined cutting edge, the difference is immaterial, but with respect to optical qualities, the difference will be quite discernable.

Thus, one will need to use a finer abrasive size with a free moving rounded particle to achieve the same reflectivity as will be achieved by a coarser sharp edged fixed particle.

I'm sure someone more familiar with optics can present this more authoritatively, but the real issue here is that refectivity alone is not the best measure of edge refinement.

Frost

Frank D.

>I have had this problem with my Norton 8000 on A2 blades. I won't attempt to explain what happens, although someone suggested it might be the metal coming off the blade leaving a different scratch pattern than the stone itself. In any case, try rinsing the stone and blade more often, and it should go away. One person said the frost went away when he started lapping directly under running water. The slurry seems to be the culprit.

Frank D. in Montreal

Re: My apologies - a Norton 8000 question

Angus Barclay, in New Zealand

>To my mind, the real test is not how the blade looks but how it cuts.

Does it really matter how shiny the blade is?

regards

Angus Barclay

Re: Frost

GolfSteve in Calgary

>Rinsing the 8000 stone prior to use seems to aid getting a shiny finish. Since I flatten my 8000 stone using a 1000 stone, and store all the stones together in one bath, I am sure that cross contamination is an influence.

The amount of pressure used during the final polish also seems to affect the shinyness. If I am aiming for shinyness when polishing the back or an iron, I increase the pressure for the final 20 or thirty strokes. If I am just doing a regular sharpening, I keep the pressure the same and usually don't rinse the stone prior to use. I end up with a frosty, but still reflective, surface.

Re: It might have been....

Kurt Loup

>Contamination could have been a problem the first time I used the stone, but I'm leaning toward flatness as the problem. It was really off. The second time I used the stone (last weekend), I pulled the garden hose over to the sharpening area and sprayed off the blade and the sharpening guide with water between changing stones. Flattening the stone and washing off the guide were the only changes I made.

Kurt

Shiny vs Matte Surfaces

Steve Elliott

>Recently I was trying to get the best edge I could on my CPM 3V blade, and made some microscope images of the results of 1 micron diamond compared to an 8000x Takenoko finishing stone.

Here is the bevel side of the blade edge after using 1 micron diamond lapping paste on a cast iron plate:

The deeper scratches are probably due to grit from a 2000x Shapton stone (9 micron) I used to flatten the lapping plate.

Although it isn't clear from the microscope image, the surface produced by diamond lapping is almost mirror-like. Here's a picture of the back of the blade after lapping with 1 micron diamond:

To see if my Takenoko finishing stone would produce a better edge than the diamond lapping, I re-honed the bevel and took the image below:

As can be seen in the image, the 8000x Takenoko stone produced a surface that looks matte to the microscope as well as to the eye. But if you compare the actual cutting edges shown on the two microscope images, they appear to be equally sharp. The number and size of the white spots on the edge correspond to sharpness, with fewer spots indicating a sharper edge. The spots are due to tiny chips, scratches, or pieces or wire edge. (I wish I had a microscope more powerful than 200x to be able to diagnose just what they are.)

For practical woodworking purposes, I haven't been able to discern any difference in performance between the edges shown above. They pass tests for sharpness to an equal degree and work well producing shavings in the .001" thickness range. After even a few passes across hard maple, the edges show noticeably more white spots along the edge, though the blade doesn't seem dull by woodworking standards.

From this I conclude that the cloudy look of an edge from a Japanese waterstone is plenty sharp even though it isn't shiny like a mirror.

Contamination

Russell Seaton

>I'll offer an opinion on contamination of waterstones from other waterstones or the medium used to flatten the stone. I don't think its anything to be concerned about. I use 60 and 80 grit silicon carbide grit to flatten my 220 waterstone. 80 and 180 to flatten my 1000 stone. 220 to flatten my 2000 stone. And 400 grit silicon carbide grit to flatten my 5000 and 8000 stones. In use I store all of the stones in the same sink in the same water and use the sink water to clean off the black swarf that is generated. When pulling a stone out of the sink to use, I will rinse it under the tap. But by no means do I consider this a super clean sterile no contamination type operation. It doesn't seem to matter. I can get nice shiney backs and bevels with the 8000 stone. Even though its been sitting in the water with all of the 220 and 1000 stone swarf.

I agree

Steve Elliott

>My technique of flattening and storing waterstones is similar to yours, and I've never noticed a problem with contamination. I take the easy precaution of rinsing the stones before use, and I don't rub stones together to flatten, but beyond that I'm not particularly careful.

In my post below, there is a 200x microscope image of an edge as it came off my 8000x waterstone, and there don't appear to be any deeper scratches from the 800x stone it is stored with.

Re: I agree

Russell Seaton

>I take the easy precaution of rinsing the stones before use, and I don't rub stones together to flatten, but beyond that I'm not particularly careful.

That just about describes my waterstone usage. Rinse the settled black stuff off before using them. Don't rub them together to flatten. I do take the extra step of changing the sink water when it becomes so black I can't see the stones any longer. I also prefer slightly warm water so after the water becomes icey cold from sitting so long, I might change it for warmer water. But this is more a luxury step to keep my hands from getting too cold. I don't think the stones care about the water temperature.

Re: My apologies - a Norton 8000 question

Dave (Arlington, VA)

>Hi John -

Thanks for your post. I haven't sharpened the bevel on these blades yet so I can't give you any feedback on how they compare to edges I would get on scary sharp.

Also, I could be mistaken, but I do think the stones are flat, and I do flatten them periodically. But your observation about the pressure I apply could be on target. I'll have to pay more attention to that when I get back to the blades.

Regards -

Dave

Re: It might have been....

Dave (Arlington, VA)

>Hi Ted-

I do think that there may have been some of the 600 grit sandpaper particles left in the stone from my earlier efforts to flatten the stone. I say this because of what appear to be "deeper" gouges that were left my the initial efforts. However, these eventually were worn away by subsequent flattening/polishing, and I didn't seem to happen later. I assumed that there might have been some looser grit on the sandpaper when it was fresh, but after usage the remaining particles remained pretty much attached to its paper substrate.

I appreciate your post. Thanks -

Dave

Re: I often wonder...

Dave (Arlington, VA)

>Hi Ryan -

I think we might be talking about different experiences. My "bands" are only about 1/8" wide. I think what you may be seeing with your experience is the difference in the steel from the portion of the blades that was hardened and quenched in oil (if its O-1). This makes the end of the blade harder than the rest of the blade and that affects its reflectivity when abraded (or, at least, so I think).

Thanks for posting!

Dave

Re: It might have been....

Dave (Arlington, VA)

>Kurt -

I may try more water. But the Norton materials say that the 8000 stone (unlike the 220, 1000 and 4000) doesn't need much water.

Dave

Re: My apologies - a Norton 8000 question

Dave (Arlington, VA)

>Hi Wiley -

Thanks for your post. I note from Russell Seaton's post above that he hasn't had much problem with contamination, but since I don't have much experience I've been careful to avoid it. I've always used fresh water for each stone. I even use a different cloth to wipe off the blades for each stone and grit level. If there's contamination, I'm inclined to think it comes from my W/D sandpaper.

Your idea of using magnification is a good one. I have one in the shop, I just haven't used it - but I will.

Thanks -

Dave

Re: My apologies - a Norton 8000 question

Dave (Arlington, VA)

>Hi Lyn -

As usual, your's was a very helpful post. This issue of reflectivity has been bugging me. I'm going to have think a bit more on your comments, but this is helping me think through a little more clearly what makes an abraded surface reflect. Heretofore, I had thought there was a direct correspondence between "flateness" and an undistorted, highly reflective surface. If I understand you correctly, I think your suggesting it may be a bit more complex than that.

Anyway, thanks for getting the juices going.

Regards -

Dave

Re: Frost

Dave (Arlington, VA)

>Frank -

Tbanks, I will try some more water. I didn't use much on my first effort. I thought that was how it was 'supposed' to be done with Norton 8000 stones. The frostiness is most pronounced on the Hock blade - but I think it is an O-1 blade.

Also "frosty" is a good description of what I'm getting. As is "matted" used by others.

Thanks -

Dave

Re: Frost

Dave (Arlington, VA)

>GolfSteve -

I appreciate the advise. I will try more pressure just to see what happens. Also, as you and others have suggested, I'll try more water.

Thanks for your post -

Dave

Re: My apologies - a Norton 8000 question

Dave (Arlington, VA)

>Hi Angus -

Your absolutely right - what matters is how it cuts, not how it looks.

What's had me stuck, however (as I mention in my relpy to Lyn above) is that I've thought there was a direct relationship between how it looks and how it cuts - i.e. a shiny, undistorted blade was flat, and the intersection of two flat planes is going to give you your sharpest edges.

But in the end you're right - I don't care how it looks only how it cuts.

Regards -

Dave