Where diamond leaves off and waterstone picks up....??

[hardheart]

Grit size is grit size, and some chromium oxide goes up to 3 micron, while others keep most all the compound at 0.5. For stones, it isn't just the abrasive type & grading, but also binder quality. Some abrasives just cut faster than others.

 

[Jason B.]

Not at all.
Potato, potatoe. Better tools work more efficiently, but grit size is grit size.

Don't forget about the shape, the shape of the abrasive particle will make it cut differently. The particle shape and material it is made from play big parts in how it abrades the steel. Its why you get a toothy edge with a diamond stone and a very smooth edge with a waterstone when using similar grits.

 

[Bill DeShivs]

But, if the edge is polished, it doesn't matter how you got there.

 

[Gotsouthern]

Thanks for the reply's fellas.

Didn't mean to get anyone fired up with my question. But I am getting some great info from some of these posts. Thank you for time and consideration, its helping me greatly to make some decisions. Even the semi-argumentative posts at least give pause for thought. I don't think I'll weigh in my opinion lol, but I am paying attention.

 

[Bill DeShivs]

I don't mean to be argumentative. Just stating that when you get to a finely polished edge, grit size begins to be the only thing that matters.

 

[hardheart]

Shape and friability still matter. If you let a waterstone create a slurry, the edge loses polish vs clean water. And some stones, mostly naturals, depend on the original grit breaking down. Coticules and Japanese naturals depend on this, and the polishing action can jump by 50%. Then novaculite and ceramic hones have the same grit size, but the compaction leaves a different finish. Grit size doesn't matter between a white and translucent Arkansas, nor between a fine and ultrafine Spyderco.

for oilstones or diamond plates, I don't see much need to investigate past micron size, but there's lots of stones out there.

 

[David Martin]

From Steve Bottorff's grit size chart http://users.ameritech.net/knives/grits.htm . Which is as good a chart as I've seen put together.He gives the white hard Ark.(if thats the one your refering) a 14 micron and hard black Ark. a 9 .When used the black Ark. leaves a different finish.To give another example. In the same chart both the black Ark. and x-fine diamond are the same micron size but in no way leave the same finish on a blades bevel. However, the Spyderco ceramic stone @ 3 microns (ultra fine @ 2 microns) leaves only a slightly different finish on a blades bevel than the black Ark.? Matrix,carrier agent? Very different size here. Whereas the CO .5 compound (green)on a strop gives a very polished finish.Grit trails expose the nature of their configuration ie. how they were formed,sharp corners or rounded imparting that to the material rubbed on them.Hence, some polish some scratch but all the same size micron.DM

 

[eKretz]

Grit size certainly isn't the only thing that matters, as quite excellently pointed out by hardheart and David.

Think about it, if the material doing the cutting/polishing is much harder than the material being cut or polished, the cutting media leaves furrows (almost perfectly identical to its shape in the case of diamond, for instance) in the material being cut similar to the grit's shape, (especially in the case of diamond grit in a diamond hone, where the diamonds are rigidly mounted, vs. in an application such as a diamond-loaded strop, where the diamonds can flex, slide and/or rotate as they and the surface being cut are dragged along the surface) so there can be many microscopic peaks and valleys with sharply defined ridges between them.

Conversely, a grit that is much closer in hardness to the material being cut/polished will tend to also be shaped/worn down by the material being polished, often changing its shape in the process. This also tends to "round off" the particles, as well as the peaks and valleys between the high and low points of the surface of the material being polished. And rest assured, even though you can't easily see them, the peaks and valleys ARE there no matter what grit size you use, and as I'm sure you know, their shape and depth plays a pretty important part in your knife's cutting and edge-holding abilities.

As you can see, there can be quite a meaningful difference in the finish provided depending on the type/shape and hardness of the abrasive grains doing the cutting or polishing, and in this case, it isn't just the size that matters.

 

[gak]

I go from "C" (coarse) diamond, to fine diamond then to waterstones on the Edge-Pro:
220
400
800
1200
Then to 2K mylar tape
then 6K mylar tape,
then to plain mylar tapes sprayed with 1 micron CBN,
then .5
then .25
then .1 micron diamond.

Sure, if you just wanna do a lazy half-assed sharpen job...

 

[gunmike1]

Sure, if you just wanna do a lazy half-assed sharpen job...

He is missing the .05 micron 3M lapping film step, definately not enough steps in there! Only 12 grits is just being lazy!

Mike

 

[Dog of War]

He is missing the .05 micron 3M lapping film step, definately not enough steps in there! Only 12 grits is just being lazy!

My usual two grit method must really suck. I only get edges that pushcut free-hanging newsprint >6" from point of hold -- OK for spreading butter, I guess.

.

 

[cotdt]

The DMT stones go up to 3 microns, which they call 8k grit, but 3 microns is more like 5k. So with waterstones, it would take over at 8k. You could also go onto 2 micron diamond paste, or lapping film.

I've found the Shapton Pros to work well with all steels, as does the DMTs. Some stones would just skate over stainless steels.

 

[Cooler]

["I only use diamond to reprofile the edge. If I'm doing that, I go from "C" (coarse) diamond, to fine diamond then to waterstones on the Edge-Pro:

220
400
800
1200
Then to 2K, and 6K mylar tapes,.
Then to plain mylar tapes sprayed with 1 micron CBN, then .5, .25 and .1 micron diamond."]

I would like to get some 1 micron CBN. Where is a good place to get it?

Also what type do you recommend? I have seen online paste which is very expensive for less than one ounce, and oil based slurry which is much less expensive.

 

[stitchawl]

You really got something against me don't you?

Every company has a set level of quality control and the higher that quality control the better the final product. For example: would you rather have chromium oxide from harbor freight or HandAmerican?

The difference between Harbor Freight's chromium oxide and that which is put out by HandAmerican is grit size. The chromium oxide used by both is the same chromium oxide.

There isn't one inferior Cr2O3 and one better Cr2O3. There is only grit uniformity differences. HandAmerican's chromium oxide works better because the grit size is more uniform and is no higher than it's specified size. Harbor Freight's chromium oxide does not work as well because its grit size varies greatly, and is often larger than the stated .5 micron advertised.

It it the final grit size that determines your edge when discussing end results. While it is true that a 15 micron diamond plate will give a different result than a 15 micron ceramic due to the shape of the cutting surfaces, once you are down to the higher grits for finish work, this no longer applies. At .25 microns you just aren't getting enough difference to matter. Once you get rid of the scratch patterns left by the previous abrasive, all you have left is the current one.


Stitchawl

 

[hardheart]

The difference in uniformity was what he was talking about. That does make one inferior to the other, particularly when some of the stuff is 3 micron instead of 0.5.

And I missed post #27 made last year. The chart gives relative finishes, but all grades of Arkansas and Spyderco ceramic stones have similar particle sizes. The difference is the density of the Arks and the production method of the Spydercos. That is why neither one is advertised at a grit rating. Arks are graded by specific gravity, because the stones that produce a finer finish are more dense, not composed of finer particles. Spyderco uses the generic 'medium' 'fine and 'ultra fine' because the alumina particles are all in the same size range, and the UF is actually just the F with the surface polished.

 

[pwet]

While it is true that a 15 micron diamond plate will give a different result than a 15 micron ceramic due to the shape of the cutting surfaces, once you are down to the higher grits for finish work, this no longer applies.

not sure, even in the micron range different abrasive of the same size will give different finishes think CrO, boron carbide and all the various powder available. depending on the abrasive shape, hardness and capacity to break down.

but what's true is that the difference will probably need a microscope to be seen at this level.

 

[Gotsouthern]

Ahh always nice to see a personal thread go all Jesus. Interesting to look back at what I had in mind then and where I'm at with it now lol. Far as I'm concerned Knifenut was spot in the first post or two there.....full set of DMT's FTW. Right now I'm still tickled with the EE as a final finisher, no stropping needed.

Ok that was way off topic from the recent posts...but hey...its my thread lol

Carry on.....

 

[Jason B.]

Diamond stones suck should have bought water stones

Seriously though I'm happy your happy

The whole grit is grit issue....... well you can think of it as all being the same but its not. I can tell the difference between 0.5 chromium oxide and 0.5 diamond, especially when used on different steels. Just because some can't does not mean its all the same.

The HF vs HA comparison is also missing many variables like binder and purity. Bar compounds are not all compound.

 

[stitchawl]

The whole grit is grit issue....... well you can think of it as all being the same but its not. I can tell the difference between 0.5 chromium oxide and 0.5 diamond, especially when used on different steels. Just because some can't does not mean its all the same.

They aren't the same. They should certainly cut faster or slower than one another, so yes, one can feel a difference. But still both will only cut at 0.5 microns, and the resulting edge from both will be polished to 0.5 microns.

The HF vs HA comparison is also missing many variables like binder and purity. Bar compounds are not all compound.

Unless you are purchasing powdered Cr2O3 and diamond dust, you are getting different binders mixed in with your compounds. Water. Oil. Wax. Who knows what else! Purity (uneven grit sizes mixed in) will really blow the numbers out of the water.

Those binders (assuming they are pure) should affect how long a compound will remain on the strop but have virtually no effect on the cutting ability of the abrasive. The ability of a compound to cut at a certain degree of size is based on the size of the largest grit found in that compound. If every grain is at 0.5 mics or below, that compound will cut at 0.5 mics. regardless of it being diamond or chromium oxide. One will be faster than the other, but not finer or more coarse.

Stitchawl

 

[pwet]

and the fact that one abrasive is harder with sharper corners and the other soft and rounder makes no difference if the same size ? they will cut the steel the same ?