EdgePro past 6k tape

A

actionyak

Joined
Feb 13, 2011
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Thanks all for your patience and help, I'm trying to consolidate opinions and experiences specifically to the following:

I currently finish knives on the metal blanks with the 3k tape. Yes, they are beyond any level of functional sharpness I would need. However, I've been bitten by the sharpening bug and would really like to create the level of sharp that has often been described on these pages. So to that end:

What would be next if I'm sharpening a knife on an EdgePro with the 6k tape mounted on a glass blank?

Gunny Bob provided this a few months ago which was most specific: What I've had good luck with is the 6K Edge Pro tape. Followed with 1 micron diamond paste stropping on cowhide, then a final strop on unloaded horsehide.

Anyone else have specific compounds and media combinations they prefer? I'm looking at the leather and balsa and felt strops that are already mounted on the EdgePro blanks, so angle will be maintained.
Perhaps a progression of the silicon carbide, boron carbide, then chromium oxide? Mounting each on leather, or balsa, or felt, or printer paper on glass, or some combination therein? Any others prefer the diamond pastes like Gunny Bob? I guess I'm just confused as to what compounds on what blanks would be the best progression to follow the 6k tape on glass with. I'd like to order the right supplies, but at the same time I don't want to order a bunch of things I won't need. I'm looking at the options on this page: http://www.chefknivestogo.com/edgepro.html

Thanks for the help!
 
Stropping on leather, or preferably balsa, will improve the edge once you get the hang of it.
 
According to the grit chart sticky, the 6k tape should be a 0.25 micron finish. And testing the finish that Ankerson put on my Manix 2, I'd say that's an accurate assessment. If you're hitting a 1 micron strop after that tape, you'd just be undoing your own work.

You can just strop on unloaded horsehide after the 6k tape, but theoretically, it would be impossible to get your edge any sharper(and if it did, I doubt you would notice it). And unless you're putting this on a kitchen knife used only for cutting fruits, vegetables(which can still dull the blade if you didn't wash all the dirt off), and boneless meat, this fine an edge would typically be ruined down to about what you'd get from a 1 micron finish within a few cuts.
 
Actually, I must question the claim that a 6K tape is equivalent to .25 micron abrasive.

I have used both the 6K and 7K tapes, extensively, and .25 diamond paste extensively. I find the appearance, at least, of a significant difference.

One must also realize that diamond compound is also available in .125, .1, .050 and .025 micron grits.

I doubt there is any practical improvement in the last two for other than razors and microtomes, but it is available for those wishing to experiment.
 
Well, I will say this... I just got off the phone the other day with Ben Dale and he said that the tapes were as follows: 2k=9 micron, 3k=3 micron, 6k= 1 micron. You can call him right now and I'm sure he would be glad to to you. Hope this helps!
 
@razor-edge-knives:
Wow, those grit-to-micron conversions are pretty interesting...!

Please be sure to tell Komitadjie so he can update The Grand Unified Grit Chart.
http://www.bladeforums.com/forums/showthread.php/856708-The-Grand-Unified-Grit-Chart
Go to the very very end of that thread to get the latest version of the conversion chart.

Komitadjie's chart shows these _approximate_ conversions for EdgePro stock stones:
EP Stock #2000 1 micron
EP Stock #3000 0.5 micron
EP Stock #6000 0.25 micron

Interesting that microns are so different for the same grit from the same manufacturer (?) (EP stones versus EP tapes).

I understand that conversion from grit to microns is basically impossible. (This is because grit is the size of filtering pores, but doesn't tell you the distribution of particle sizes before filtering. Also, I don't know if manufacturers "adjust" grit sizes based on how agressively the abrasive cuts (ie: diamond cuts faster than aluminum oxide).)

Also it is unusual that if 2k=9 microns, then I would have expected that 3k=6 micron and 6k=3micron. Interesting that this is not true for the tapes.

-------------------------------------------------------------
"What grit sharpens the mind?"--Zen Sharpening Koan
 
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yeah, it is very interesting... there is something not quite right here... either with the tapes or the original micron rating on the stones. one of the two is off. i dont' know how we can tell, i'm just telling you what ben dale told me =) the 1000 grit can't equal a lower grit than the 2k tape, that won't work and isn't true b/c i definitely achieve a higher polish when going between the two.

thanks for the tim, me and kom keep in contact regularly and i have notified him. :D

i will say that, after using the stop collar trick, i can get a straight razor sharp enough to pass the hanging hair test after finishing the edge on the 6k tape. that would, in my mind, HAVE to make it somewhere around 1 micron or less...
 
This chart also seems off:
http://zknives.com/knives/sharpening/edgeproapex.shtml

Says the 1000 grit stone is 1.8 micron while the 2k tape is 9 micron.

Reading back my message from Ankerson, he says he used Mother's Mag polish, applied on the 6k tape if I read it right.

Not sure how fine that is, but it definitely seems in the neighborhood of 0.5 microns easy.

I also find it interesting that a finer abrasive on top of a coarser one works so well(maybe it was a very worn 6k tape?). Makes me want to try my diamond spray on a worn out 12000AO belt to see if I can get the same effect on my WorkSharp. Unfortunately, those damn things seem to last forever:D.
 
Until such time as there is an international "standard" for all abrasives, that is undisputed by different professional organizations, I fear that we are pretty much limited to personal experimentation.

A shame, really. Using current measurement devices, and scientific methodology, it would be quite elementary for a panel of experts to arrive at a standard if those with similar interests would be willing to support the effort and accept the results.
 
I used to read one of Ken Schwartz's sharpening blogs, and I'm sad that it seems to have disappeared.

I mean this one:
http://precisesharpening.blogspot.com/

Ken Schwartz seems to have a different blog now:
http://preciseknifesharpening.blogspot.com/

However, a lot of content in the first blog is now simply gone. :(

In the original blog, Ken Schwartz had some of his abrasive sprays sent off to a scientific lab, so that the distribution of particle sizes could be analyzed. He showed histograms of particle sizes. I thought this was super-cool. The peak of the particle sizes look very Gaussian to me (ie: standard bell-curve or normal-distribution in statistics/probability). So that looks like it could be very well characterized by an average size (mean) and a standard-deviation.

Ken Schwartz also showed that some "competitor" compounds were a mixture of particles of different sizes. I don't know if that is necessarily bad, since in my mind rather complicated things can happen: Suppose the larger abrasives are of a softer abrasive, then the scratches they make will be smaller for a given particle size. Is a mixture of different types of abrasives bad? I have no idea. Some particles might be more friable than others (ie: break up into sharp smaller pieces which continue to cut, as opposed to getting their corners rounded off); these friable particles might be designed to be fractured by the other abrasive type. I really don't know enough about materials science, surface-physics, and tribology to know what's going on here. http://en.wikipedia.org/wiki/Tribology All this is wild speculation of course (on my part).

But I could imagine that some specially designed mixtures deliberately have different types abrasives mixed in at different sizes, and I can imagine this is done deliberately with precise engineering and experimentation to optimize it.

And of course, I can imagine that some manufacturers are simply being cheap, and substituting a fraction of their poly-crystaline diamond with something much cheaper, like aluminum oxide, and hoping the customer won't know the difference.

I wish other companies would either do histograms, give us a average particle size with standard deviation, or else give minimum and maximum particle sizes. Some places do give minimum and maximum particle sizes for diamond pastes, which is good. But I don't know what the distribution actually looks like.

I do have some "Green Veritas Honing Compound" from www.leevalley.com. This is a mixture of chrome-oxide and aluminum-oxide. They don't mention the particle size, but they say that the "scratch size" is 0.5 microns. That too is interesting. For example, another possible standard is to take the abrasive, and drag it over a standard surface (say, a specific steel heat-treated a specific way) with a standard pressure applied to it. Then one could take an image of the scratch pattern, and do statistics on it: average scratch width/depth etc. Of course, this isn't so simple in practice (ie: what is a scratch? Where does one scratch stop and where does another start?). But there _are_ engineering standards for surface roughness, such as rms smoothness (root-mean-square). Maybe those could be used.

One potential advantage of the "standard scratch test" is that it would partly account for different types of abrasives making different sizes of scratches, even if the particles are the same size. This would partly adjust for effects such as particle hardness, particle shape, and friability.

This is probably all over-kill for knife-sharpening. However these types of concerns must surely matter for people doing precision optical polishing, and also manufacturers of diamond microtome knives. Those darn diamond microtome knives are sharp all the way down to 0.005 microns, which is something like 30 carbon atoms wide, and is way below optical wavelengths (which range from around 0.4 microns to 0.7 microns).
http://www.tedpella.com/diamond_html/diamondk.htm

Okay, sorry to speculate and rant so much. I'm just a bit frustrated that if I mix and match abrasives from different manufacturers, it's often rather complicated to figure out which grit is actually finer because the numbers mean different things for different products!

Sincerely,
--Lagrangian

P.S. There are international engineering standards for abrasive grit sizes (see The Grand Unified Grit Chart) such as JIS, ANSI, FEPA etc. I don't now what they mean. I hope to learn about them. If you know of any good information or links about them, please chime in. :)

-------------------------------------------------------------
"What grit sharpens the mind?"--Zen Sharpening Koan
 
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@Noctis3880:

I couldn't find the original source... but _somewhere_ I heard that _some_ metal polishes break down as you use them. That is, they are made with abrasive particles which are designed to _easily_ break into smaller and smaller ones. I don't know if this is true or not, so don't quote me on this one! And I can't remember where I heard about this. :(

But if it is true, then it's kind of hard to give a "grit number" to a polish like this.

If you find out more about your metal polish, let us know. :)
 
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Lagrangian said:
@Noctis3880:

I couldn't find the original source... but _somewhere_ I heard that _some_ metal polishes break down as you use them. That is, they are made with abrasive particles which are designed to _easily_ break into smaller and smaller ones. I don't know if this is true or not, so don't quote me on this one! And I can't remember where I heard about this. :(

But if it is true, then it's kind of hard to give a "grit number" to a polish like this.

If you find out more about you metal polish, let us know. :)
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While I believe it happens on some level, I don't believe it affects the finish to the extent where one grit behaves like another or leaves a finish like a smaller grit. At most I think it will just affect the sharpening speed, but not the final finish to the edge.

In short, it means my 12000AO belt won't ever replace my 1 micron diamond loaded strop:thumbup:.

To elaborate on that, imagine a floor littered with basketballs and tennis balls, enough to cover the whole floor. Next, imagine dropping a large flat board of wood(very large) onto the floor. Chances are, the board will only touch the basketballs. The presence of tennis balls doesn't matter, as that board will only touch the basketballs. I imagine much the same happens to abrasives. Thing is, it's beneficial to have more of the large size abrasives in order to cut faster. And the abrasive breakdown probably wouldn't matter unless all the abrasives were broken down extremely quickly, or there are enough small abrasives to completely cover up the large abrasives(slurry on top of a waterstone).
 
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Wow, what a wealth of information. Thanks! I think I'm going to go with the 6k tape on a glass blank, followed by green chromium oxide on balsa, followed by untreated leather. I think from what I've read that should give me a progression to a finer and finer polish. The biggest wrinkle I suppose would be whether the 6k tape is .25 micron or 1 micron. I'll report back my impressions after trying that progression.
 
Noctis3880 said:
This chart also seems off:
http://zknives.com/knives/sharpening/edgeproapex.shtml

Says the 1000 grit stone is 1.8 micron while the 2k tape is 9 micron.

Reading back my message from Ankerson, he says he used Mother's Mag polish, applied on the 6k tape if I read it right.

Not sure how fine that is, but it definitely seems in the neighborhood of 0.5 microns easy.

I also find it interesting that a finer abrasive on top of a coarser one works so well(maybe it was a very worn 6k tape?). Makes me want to try my diamond spray on a worn out 12000AO belt to see if I can get the same effect on my WorkSharp. Unfortunately, those damn things seem to last forever:D.
Click to expand...

I think Mothers Mag Polish is less than .25 Micron.

I polish the 6K grit tapes with it until they look like glass then continue.
 
I'm with Ben Dover, I highly doubt the 6k tape is .25 micron. The level of polish is wrong from the pictures I have seen and the discussion of its sharpness would be much different. I've also seen a 3k tape edge from a EP and its scratch pattern is too large for a .25 micron abrasive to follow.
 
@Ankerson:

Whoa... I always thought about polishing my knives.
But I never thought about polishing my grits!

Thanks for the tip :)
 
Ankerson said:
I think Mothers Mag Polish is less than .25 Micron.

I polish the 6K grit tapes with it until they look like glass then continue.
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Hmm, that's interesting. Not sure how that works out though. Does the Mother's Mag cover the tape over or does it actually polish the abrasive on the tape? I would think that in order to have that effect, the smaller abrasive would have to be harder than the larger abrasive in question. Or would you say you polished the previous abrasive off the tape and left the Mother's Mag polish in its place?

Again, I'm thinking of something along the lines of 0.25 micron diamond spray, but on a WorkSharp belt, as I have yet to find any well-made leather belts in that size. Kind of wondering if I could do the same by applying the spray to a micro-fiber cloth and then pressing that cloth against the belt while it's running.
 
Noctis3880 said:
Hmm, that's interesting. Not sure how that works out though. Does the Mother's Mag cover the tape over or does it actually polish the abrasive on the tape? I would think that in order to have that effect, the smaller abrasive would have to be harder than the larger abrasive in question. Or would you say you polished the previous abrasive off the tape and left the Mother's Mag polish in its place?

Again, I'm thinking of something along the lines of 0.25 micron diamond spray, but on a WorkSharp belt, as I have yet to find any well-made leather belts in that size. Kind of wondering if I could do the same by applying the spray to a micro-fiber cloth and then pressing that cloth against the belt while it's running.
Click to expand...

I can see a reflection in the tape....
 
Reporting back on my test:

I'm not 100% sure if it worked or not. The resulting edge behaved slightly differently than what I'm used to.

But backing it up a bit, I had an old 12000AO belt that I slapped Veritas CrO compound on, which seems to be closer to 6-9 micron in finish rather than the 0.5 micron it claims to be. I first mashed a belt cleaner block that I got from Woodcraft onto the belt to remove the compound, which mostly seemed to work. Then I pressed P60 grit sandpaper onto the belt while running to wear it down quickly, and went back to the belt cleaning block again. I then sprayed some 0.25 micron Dupont Diamond Spray onto a cloth, which I didn't really like because it stayed really wet and ruined my strop, as well I was dubious about its actual effectiveness. I rubbed that cloth against the belt a few times, then sprayed the belt itself and dried it off a bit(but I mostly ran it in the sharpener to fling the rest of it off).

I sharpened up my Mora as usual and used the belt in lieu of a strop. The edge was interesting to say the least. It didn't seem to blaze through thick hair like my Manix 2 did(which Ankerson sharpened), but when I ran it over my leg hairs(not on the skin), a few would pop off a greater distance than they normally would, and I really don't feel anything so it's hard to notice when they've been cut. Running it on my leg on the skin, the hairs would come off, but without much drag or resistance. I wasn't able to push cut toilet paper(which I think is a myth anyway), though I was able to slice it very crisply, like I was just cutting regular printer paper.

Seems sharper than my usual 12000AO finish(about 2-3 microns I believe), but I can't really say for sure that it's a 0.25 micron finish.

I don't suppose anyone came up with a definitive test to distinguish a 0.25 micron edge from a 1 micron?
 
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