sharpening grit comparisons with pics (long)
Oct 28, 2013 17:28:37 GMT
Post by Lord Cobol on Oct 28, 2013 17:28:37 GMT
So I've been trying to learn sharpening, spending the money on sharpeners that most of you would have spent on swords. One could say I've been trying to buy my way out of sharpening incompetence and up to mere mediocrity. I've been buying mostly stuff that can be used dry, partly out of plain cussedness and partly because I wanted to sharpen indoors without getting oil or water all over everything. Also I'm paranoid about rust, don't want to use water at all.
Along the way I couldn't help noticing that different companies grit/micron ratings didn't always compare directly with each other or with user comments. Example, the Spyderco fine stone (302f) is rated by the manufacturer at 1800 grit, but I've seen users who claim to know more than I claim to know rate it at 3000 or 8000. And it doesn't take organized testing to see that it is much finer than DMT's fine, which in turn is much finer than Norton's Crystolon fine.
So I decided to run some tests. For the tldr crowd, results come first, from coarsest to finest. Description of how I tested comes after. Details on specific brands & products come in reply posts later.
Results: Blank lines separate noticeable differences. Single-spacing indicates results too close to call with 100% certainty. There may be a big difference between the top & bottom of a single-spaced group, but if the difference between two adjacent items had been clear-cut, they would have been double-spaced.
DMT DuoSharp extra-coarse, 220 grit
Norton $5.98 silicon-carbide, coarse side, 100 grit (Crystolon)
Norton $7.99 economy aluminum-oxide, brown side
Norton $7.99 economy aluminum-oxide, light-grey side
DMT DiaFold coarse 325 grit lightly broken-in
DMT DuoSharp coarse 325 grit moderately broken-in
DMT DiaFold fine 600 grit lightly broken-in
Norton $5.98 silicon-carbide, fine side, 280 grit
India aluminum-oxide coarse (100 grit?)
sandpaper: 400 grit 3M wet-or-dry (worn)
DMT DuoSharp Fine 600 grit lightly broken-in
Spyderco Medium 302M
sandpaper: 600 grit Norton wet-or-dry (fresh)
DMT DuoSharp extra-fine 1200 grit, 9 microns
DMT DiaFold extra-Fine 1200 grit, 9 microns
sandpaper: 600 grit Norton wet-or-dry (worn)
DiaFold extra-extra-fine, 8000 grit, 3 micron
sandpaper: 1000 grit 3M (fresh)
India aluminum-oxide fine side, 320 grit (?)
Spyderco fine 302F
strop: black compound
sandpaper: 2000 grit 3M
Dia-Ppaste 6 micron
Spyderco ultra-fine 302UF
sandpaper: 3000 grit 3M Trizact (worn)
strop: mothers mag
strop: white compound
strop: green compound 0.5 micron
strop: no compound.
As I ran repeated tests on different blades the results did not always line up. Sandpaper might wear; DMTs might get more broken-in, but mostly things just wouldn't match exactly for no good reason. The list above is a compromise: if “A” was finer than “B” in two tests but slightly coarser in another, I'd grumble and list it as single-spaced slightly finer.
After DMT DuoSharp extra-coarse
After Norton Crsytolon coarse side
DMT DuoSharp coarse
DMT Duosharp fine
DMT DuoSharp extra-fine
India stone, fine side
Spyderco ultra-fine 302UF
Green compound
strop with nothing
Summary ratings:
coarse: DMT extra-coarse thru DMT coarse (the top 6)
medium coarse: diafold fine, silicon-carbide fine, India coarse
medium: 400 grit sandpaper, duosharp fine, spyderco medium
medium fine: DMT extra-fine, & extra-extra-fine, 600-grit sandpaper
fine: 1000-grit sandpaper thru white compound
extra-fine: strop with both green compound, then nothing
------------------------------------
How I picked items to test:
I was trying to find *affordable*, long-term cost-effective ways to sharpen *indoors* without oil or water. (And yes, I know it is strange to complain so much about cost and then spend hundreds of dollars on so many redundant sharpeners).
1: Long-lasting items had to be sort-of affordable; less durable ones had to be really affordable.
2: Everything had to be usable dry or else be cheap enough so I wouldn't mind destroying it. No oil or water; so no expensive Japanese water stones.
3: I didn't test coarse sandpapers because I had previously concluded that $5.98 Norton coarse/fine stone was much more cost-effective.
4: I've developed a bias against even fine sandpaper; a big part of my spending spree and testing was motivated by a desire to find long-lasting items that would be more cost-effective than fine sandpaper too. So I tested fine sandpapers barely enough to get an idea how they compared, then put them aside to save for times when I need something flexible. Just humor me.
5: I wanted to test multiple brands, but I also wanted to test a range of items for each brand more than I wanted to test every brand around. Norton was an easy choice because of price. The choice of DMT & Spyderco was pretty arbitrary. Humor me again.
6: Goal was to sharpen moderate-price swords, machetes, etc. Not high-end collector stuff.
-------------------------
How I tested:
Sharpening & stropping were done freehand, mostly with the same motion I would use to put a convex edge on a sword or machete: blade towards me, moving it away in a long stroke and gradually raising the back, sometimes starting diagonally back, but ending each stage straight back so the grind marks in my photos would be comparable. Some sharpening was done with a shorter back-and-forth motion, especially on the Spydercos because they weren't perfectly flat and the shorter motion let me avoid the worst parts.
The strops were jeans glued to hardwood with no padding, so they had less "give" than leather.
The victims were used box-cutter blades chosen not out of any great need for sharp box cutters, but because I wanted lots of something cheap / disposable / small / easy to sharpen for a series of tests.
I started with what I expected to be the coarsest sharpener and worked down in order of expected fine-ness. If I found something coarser than I expected I would go back thru the previously-done (actually) finer ones. In each step I tried to work on it enough to obliterate scratches from the prior step -- more work than I would have done if mere sharpening in stages had been the goal.
Everything was done dry. Stones were rinsed off at the end of a day's testing.
Pics were taken with a SuperEyes B005 USB microscope, with the hood off and the end of the tube pressed against the blade laying on a sheet of paper. Lighting, glare amd sometimes focus are poor, but magnification is ok, and USB scopes are great for taking pictures. Mine costs about $30 on Amazon; more money will get something with much better specs. I'm tempted.
Sharpness of finer grits were double-checked by slicing paper and listening to the sounds.
Initial test included the cheap silicon-carbide Norton, all my DMTs (including Dia-Paste), Spyderco F & UF, black/white/green compound.
Later I focused on the ones I omitted the first time: India brand-x, economy aluminum-oxide, Spyderco medium, mother's mag and sandpaper; plus some re-tests of the above. Basically, if item "x" from a test on a new blade seemed close to items "b" & "c" from a prior test, I would attack the new blade with "b" & "c"and go back & forth between them and "x" until I had an idea of the difference.
There were lots of follow-up tests. For example, test 7 focused on the all-cheap approach: Norton coarse/fine, then stropping with black compound then white, green & nothing (hint: it worked pretty well). Test 8 rushed thru my DMTs up to "extra-fine", then spent an hour going back & forth between my DMT extra-fines and extra-extra-fine and other items that scored close to them before: black compound, India fine, and Spyderco fine. Test 10 focused on my late-arrival spyderco medium. Test 12 was the complete review -- I did everything in order (except the Mother's Mag).
Any plausible sequence of medium & fine items from my collection seems to make a decent convex edge on a slightly dull cheap kitchen knife, as long as I finish by stropping with green compound & "nothing". By "decent" I mean it takes hair off my arm and slices paper easily. For some reason I can't seem to get box cutter blades that sharp.
----------------------------
Conclusions of these tests:
1: It is possible to get decent results on the cheap.
2: I am too talkative.
3: To a nerd with a USB microscope, everything looks like an excuse for a close-up picture.
4: The rest of you need to get microscopes and test other sharpeners on other types of steel.
----------------------------
Grit / micron conversion charts all all over the internet:
www.imcclains.com/productinfo/do ... 0Chart.pdf
www.razorandstone.com/showthread ... son-Charts
www.wickededgeusa.com/index.php? ... &Itemid=46
home.earthlink.net/~litefrozen/d ... _chart.pdf
www3.telus.net/BrentBeach/Sharpe ... 6.html#ab6
www.metalclayuk.co.uk/asp/MicronsGrits.asp
Most of them don't go down as fine as I would like, and they mostly cross-reference different systems of measuring particle size without saying much about differences in material.
They don't all agree. 0.5 microns (official spec of my green compound) might be 15,000 grit or 30,000 grit depending on where you look.
Maybe if I had read and deciphered more charts first I wouldn't have felt the need to do so much testing myself (?). I swear I did read some but I didn't find the better ones until after most testing was done.
But without checking for myself, I can't trust what I read anyway. The bowlers chart lists Scotch-Brite nylon pads green as 600 grit and blue as 1000. Sounds plausible, but when I used Scotch-Brite pads on some rusty steel, the blue "non-abrasive" did nothing and the green "heavy duty" scratched the bleep out of the steel. No way is that *just* the difference between 600 and 1000 grit without something else going on.
The wickededge chart has nice pictures. Someone has a better microscope than I do -- and a bigger budget for high-end stones. The chart looks like it is in order coarse-to-fine, but some pictures have scratch patterns that are way out of sequence. More evidence that particle size and official ratings don't mean much.
Razorandstone has a neat graph of speed vs sharpness, which gives few numbers but covers the differences between materials better than anything else I have found. For example, it says silicon carbide coarse is much coarser but much slower than diamond extra-coarse. I'd tentatively rate it as slower and almost/about as coarse. They call the x-axis dull/sharp; I'd rather call it "coarse/fine".
Coming soon - mini-reviews:
Norton
stropping & misc
Spyderco
DMT
Along the way I couldn't help noticing that different companies grit/micron ratings didn't always compare directly with each other or with user comments. Example, the Spyderco fine stone (302f) is rated by the manufacturer at 1800 grit, but I've seen users who claim to know more than I claim to know rate it at 3000 or 8000. And it doesn't take organized testing to see that it is much finer than DMT's fine, which in turn is much finer than Norton's Crystolon fine.
So I decided to run some tests. For the tldr crowd, results come first, from coarsest to finest. Description of how I tested comes after. Details on specific brands & products come in reply posts later.
Results: Blank lines separate noticeable differences. Single-spacing indicates results too close to call with 100% certainty. There may be a big difference between the top & bottom of a single-spaced group, but if the difference between two adjacent items had been clear-cut, they would have been double-spaced.
DMT DuoSharp extra-coarse, 220 grit
Norton $5.98 silicon-carbide, coarse side, 100 grit (Crystolon)
Norton $7.99 economy aluminum-oxide, brown side
Norton $7.99 economy aluminum-oxide, light-grey side
DMT DiaFold coarse 325 grit lightly broken-in
DMT DuoSharp coarse 325 grit moderately broken-in
DMT DiaFold fine 600 grit lightly broken-in
Norton $5.98 silicon-carbide, fine side, 280 grit
India aluminum-oxide coarse (100 grit?)
sandpaper: 400 grit 3M wet-or-dry (worn)
DMT DuoSharp Fine 600 grit lightly broken-in
Spyderco Medium 302M
sandpaper: 600 grit Norton wet-or-dry (fresh)
DMT DuoSharp extra-fine 1200 grit, 9 microns
DMT DiaFold extra-Fine 1200 grit, 9 microns
sandpaper: 600 grit Norton wet-or-dry (worn)
DiaFold extra-extra-fine, 8000 grit, 3 micron
sandpaper: 1000 grit 3M (fresh)
India aluminum-oxide fine side, 320 grit (?)
Spyderco fine 302F
strop: black compound
sandpaper: 2000 grit 3M
Dia-Ppaste 6 micron
Spyderco ultra-fine 302UF
sandpaper: 3000 grit 3M Trizact (worn)
strop: mothers mag
strop: white compound
strop: green compound 0.5 micron
strop: no compound.
As I ran repeated tests on different blades the results did not always line up. Sandpaper might wear; DMTs might get more broken-in, but mostly things just wouldn't match exactly for no good reason. The list above is a compromise: if “A” was finer than “B” in two tests but slightly coarser in another, I'd grumble and list it as single-spaced slightly finer.
After DMT DuoSharp extra-coarse
After Norton Crsytolon coarse side
DMT DuoSharp coarse
DMT Duosharp fine
DMT DuoSharp extra-fine
India stone, fine side
Spyderco ultra-fine 302UF
Green compound
strop with nothing
Summary ratings:
coarse: DMT extra-coarse thru DMT coarse (the top 6)
medium coarse: diafold fine, silicon-carbide fine, India coarse
medium: 400 grit sandpaper, duosharp fine, spyderco medium
medium fine: DMT extra-fine, & extra-extra-fine, 600-grit sandpaper
fine: 1000-grit sandpaper thru white compound
extra-fine: strop with both green compound, then nothing
------------------------------------
How I picked items to test:
I was trying to find *affordable*, long-term cost-effective ways to sharpen *indoors* without oil or water. (And yes, I know it is strange to complain so much about cost and then spend hundreds of dollars on so many redundant sharpeners).
1: Long-lasting items had to be sort-of affordable; less durable ones had to be really affordable.
2: Everything had to be usable dry or else be cheap enough so I wouldn't mind destroying it. No oil or water; so no expensive Japanese water stones.
3: I didn't test coarse sandpapers because I had previously concluded that $5.98 Norton coarse/fine stone was much more cost-effective.
4: I've developed a bias against even fine sandpaper; a big part of my spending spree and testing was motivated by a desire to find long-lasting items that would be more cost-effective than fine sandpaper too. So I tested fine sandpapers barely enough to get an idea how they compared, then put them aside to save for times when I need something flexible. Just humor me.
5: I wanted to test multiple brands, but I also wanted to test a range of items for each brand more than I wanted to test every brand around. Norton was an easy choice because of price. The choice of DMT & Spyderco was pretty arbitrary. Humor me again.
6: Goal was to sharpen moderate-price swords, machetes, etc. Not high-end collector stuff.
-------------------------
How I tested:
Sharpening & stropping were done freehand, mostly with the same motion I would use to put a convex edge on a sword or machete: blade towards me, moving it away in a long stroke and gradually raising the back, sometimes starting diagonally back, but ending each stage straight back so the grind marks in my photos would be comparable. Some sharpening was done with a shorter back-and-forth motion, especially on the Spydercos because they weren't perfectly flat and the shorter motion let me avoid the worst parts.
The strops were jeans glued to hardwood with no padding, so they had less "give" than leather.
The victims were used box-cutter blades chosen not out of any great need for sharp box cutters, but because I wanted lots of something cheap / disposable / small / easy to sharpen for a series of tests.
I started with what I expected to be the coarsest sharpener and worked down in order of expected fine-ness. If I found something coarser than I expected I would go back thru the previously-done (actually) finer ones. In each step I tried to work on it enough to obliterate scratches from the prior step -- more work than I would have done if mere sharpening in stages had been the goal.
Everything was done dry. Stones were rinsed off at the end of a day's testing.
Pics were taken with a SuperEyes B005 USB microscope, with the hood off and the end of the tube pressed against the blade laying on a sheet of paper. Lighting, glare amd sometimes focus are poor, but magnification is ok, and USB scopes are great for taking pictures. Mine costs about $30 on Amazon; more money will get something with much better specs. I'm tempted.
Sharpness of finer grits were double-checked by slicing paper and listening to the sounds.
Initial test included the cheap silicon-carbide Norton, all my DMTs (including Dia-Paste), Spyderco F & UF, black/white/green compound.
Later I focused on the ones I omitted the first time: India brand-x, economy aluminum-oxide, Spyderco medium, mother's mag and sandpaper; plus some re-tests of the above. Basically, if item "x" from a test on a new blade seemed close to items "b" & "c" from a prior test, I would attack the new blade with "b" & "c"and go back & forth between them and "x" until I had an idea of the difference.
There were lots of follow-up tests. For example, test 7 focused on the all-cheap approach: Norton coarse/fine, then stropping with black compound then white, green & nothing (hint: it worked pretty well). Test 8 rushed thru my DMTs up to "extra-fine", then spent an hour going back & forth between my DMT extra-fines and extra-extra-fine and other items that scored close to them before: black compound, India fine, and Spyderco fine. Test 10 focused on my late-arrival spyderco medium. Test 12 was the complete review -- I did everything in order (except the Mother's Mag).
Any plausible sequence of medium & fine items from my collection seems to make a decent convex edge on a slightly dull cheap kitchen knife, as long as I finish by stropping with green compound & "nothing". By "decent" I mean it takes hair off my arm and slices paper easily. For some reason I can't seem to get box cutter blades that sharp.
----------------------------
Conclusions of these tests:
1: It is possible to get decent results on the cheap.
2: I am too talkative.
3: To a nerd with a USB microscope, everything looks like an excuse for a close-up picture.
4: The rest of you need to get microscopes and test other sharpeners on other types of steel.
----------------------------
Grit / micron conversion charts all all over the internet:
www.imcclains.com/productinfo/do ... 0Chart.pdf
www.razorandstone.com/showthread ... son-Charts
www.wickededgeusa.com/index.php? ... &Itemid=46
home.earthlink.net/~litefrozen/d ... _chart.pdf
www3.telus.net/BrentBeach/Sharpe ... 6.html#ab6
www.metalclayuk.co.uk/asp/MicronsGrits.asp
Most of them don't go down as fine as I would like, and they mostly cross-reference different systems of measuring particle size without saying much about differences in material.
They don't all agree. 0.5 microns (official spec of my green compound) might be 15,000 grit or 30,000 grit depending on where you look.
Maybe if I had read and deciphered more charts first I wouldn't have felt the need to do so much testing myself (?). I swear I did read some but I didn't find the better ones until after most testing was done.
But without checking for myself, I can't trust what I read anyway. The bowlers chart lists Scotch-Brite nylon pads green as 600 grit and blue as 1000. Sounds plausible, but when I used Scotch-Brite pads on some rusty steel, the blue "non-abrasive" did nothing and the green "heavy duty" scratched the bleep out of the steel. No way is that *just* the difference between 600 and 1000 grit without something else going on.
The wickededge chart has nice pictures. Someone has a better microscope than I do -- and a bigger budget for high-end stones. The chart looks like it is in order coarse-to-fine, but some pictures have scratch patterns that are way out of sequence. More evidence that particle size and official ratings don't mean much.
Razorandstone has a neat graph of speed vs sharpness, which gives few numbers but covers the differences between materials better than anything else I have found. For example, it says silicon carbide coarse is much coarser but much slower than diamond extra-coarse. I'd tentatively rate it as slower and almost/about as coarse. They call the x-axis dull/sharp; I'd rather call it "coarse/fine".
Coming soon - mini-reviews:
Norton
stropping & misc
Spyderco
DMT