Coarse edge stropping

Heavy, Thanks for making the effort to conduct atleast some testing, enough to draw a informed conclusion on the matter . Which is far better than some others . If you conduct tests as sound as your writing abilities, I'd say your on solid ground . I'll wait on your further comments . Thanks again for putting forth the effort . DM
 
HeavyHanded said:
Yeah, I did a test a while back involving Aus6,Aus8, 154cm, 14c28n, and VG1, as well as side by side tests with just Aus8 and VG1. The fine edge was what came off my fine Arkansas and followed up with a Franz Swaty hone - painfully time consuming but "hair whittling" sharp though not quite what I can now get from my translucent Arkansas and CO strop. Coarse edge was from a 60 grit SiC stone. Right off the bat the 154cm, 14c28n Sandvik, and the VG1 didn't take a coarse edge that well - it just didn't feel or look like the grind on the stone was "imprinting" in the steel like it does on the Aus and 440c steels (IME Buck's 420HC is one of if not the best steels for a coarse edge followed by 440c and then Aus8). This jibes with what I found doing side-by-side with two CS Voyagers, one Aus8 and the other VG1. The Aus8 took the edge better and held it far longer than the VG1 (I almost sent it back to CS with a nastygram). However, the VG1 takes a better fine edge and it lasts longer than the Aus8 by quite a bit. I have not tested VG10, but from the number of folks that have reported chipping on ceramic hones with this steel, I have to assume it won't respond well to large-grit media. This could very well be one of the reasons so many people have nothing good to say about coarse edges in general, the steel they're using might not be conducive to it, and the stone they're using might not work well for it. I've never used the DMT 120 grit, but for a lot of "fine-edge aficionados" this stone is probably their only coarse, doesn't seem to do a very good job for this application, and they're probably trying it out on some very ceramic-like steels. The ability of the steel to cleanly accept the grind pattern, and the media to present a good grind, is essential to good performance IMO. The other factor in addition to these, is that for a lot of folks "coarse" can be as fine as 600 grit - not very coarse in my book.
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Thanks for that! Your experiences do give me something to work from and think about! Excellent work on writing it out as well. :thumbup:

Also, I apologize for stating to stray off-topic slightly. I do want to continue to hear what your experiences have shown on stropping coarse edges. :)
 
I my self have often found a great edge with a lower grit finish straight to the strop.

On one knife that I made, I went from a 200 grit straight to the strop (Mostly just wanted to test the edge retention real quick to see if I had done a half way decent back yard heat treat in).

That edge was screaming sharp. Eventually, of course, even with a coarse edge, a loaded strop will make it polished.

For most edges I take it to sandpaper with 200, 330, 400, then 600 grit. I normally don't go higher than 600 grit before going to the loaded strop. I have been known to skip this occasionally, or just hit the very edge with the 600 to remove the wire edge, then strop it.




People will always holler and yell if you say you don't go up to a 10,000 grit before moving on to the magical dust from the wings of an endangered butterfly.

If it cuts well, and holds and edge as long as you want, that is all that matters.
 
Bigfattyt said:
I my self have often found a great edge with a lower grit finish straight to the strop.
People will always holler and yell if you say you don't go up to a 10,000 grit before moving on to the magical dust from the wings of an endangered butterfly.

If it cuts well, and holds and edge as long as you want, that is all that matters.
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I know exactly what your saying . DM
 
Previous was off topic but on current subject . I had rather discuss the topic .
Just reading and thinking about what Heavy is saying . It could be the rule of thumb is: that large grain steels may be sharpened on coarse stones (large grain) and the finer (smaller) grain steels take a better edge from the finer grits . ? DM
 
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Coarse and fine grain could be one way to look at it, like VG 10 for example was designed with a fine grain and to be sharpened to a high finish. Makes sense that it would perform best at a high grit as it was designed to. A steel like S30V AFAIK is a fine grain steel but not very good at being highly refined in the edge. I think the issue that complicates what could be a good "coarse/fine grain" standard for how to sharpen a edge is the factor of extreme wear resistance. As a average though if we leave out PM steels it would probably work well as a standard for what may work best with a given steel.

DM, relax man your the only one stressing.

Heavy, good work on the testing have you ever tried different abrasives with the same steel?
 
It may be worth investigating that, with the exception of 440C, the steels Heavy found to take the best coarse edges were low carbide volume steels. Possibly also VG-1. I don't know that much about it. My old Buck Scoutlite in 425 Modified takes a hair whittling edg off a 220 grit waterstone. I really need to put that edge back on it and see how it holds up. Also, on belt sander sharpened knives, I usually stop at 180 to 220 grit, the strop with the powered belt. These will last a long time as well.
 
knifenut1013 said:
Heavy, good work on the testing have you ever tried different abrasives with the same steel?
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Only at normal grit ratings (300 - 8000). Much like yourself, and many others here I've noticed that some steels do not respond well to all grinding media.

To the best of my knowledge there's only two types of grinding media commonly available at under 100 grit, SiC and AO, with the later generally stuck to a belt. This really limits what can be done to test in this area, but how much larger a grit could you really go than the 60-80 range? If you're aware of any other materials I could be testing in this range, let me know! I know that belts come as large as 36 grit, but can one really hand sharpen on this? Once you put it on a belt, your results are going to be very different. A 320 grit power belt-sanded edge looks like a 1000 grit or better off a hand stone (IME).

HH
 
I used belts for about a year by hand before buying a belt sander. They can be cut up and attached to a board or other backing. I even did a full convex regrind to a Schrade Peanut with just belts and sandpaper strips stretched tight after clamping to a table, 80 to 600 grit.
 
VERY interesting guys! I love it when people think outside the box, and challenge the establishment. I can't say that it always works out though. :D

One thing I think I hear is that this very coarsely sharpened edge works better with softer steels, and the reason for that is very simple. Soft steel dulls more quickly than hard steel when both have a refined edge. No arguments there. A coarsely ground edge on soft steel probably works better because it acts like a serrated blade, and with the soft steel, the "teeth" don't break off, but on hard steel they do. Does that make sense?
 
Yes and no, or better yet...maybe. Aus8 and 440c can both hit RH 60, and certainly RH 58-59 is very hard. I believe it has a lot more to do with the composition of the steel, but I don't know enough about that to even speculate. I will reiterate one thing I feel is a misconception re coarse edges - namely that they cut with their teeth. My coarse edges appear to have a lot more back and forth, up and down along the edge, but have very few if any "teeth" that are large or numerous enough to do any cutting. Think of it more like a napped flint edge perhaps. If done well, mine look very much like a fine edge under magnification, but on a much larger scale. Just like pushing a fine edge to the extreme, a lot of smaller variables start to become a little more critical when you get to the margins, I just don't know what all they are, only what I'm observing and what other folks are saying about this or that steel or edge bevel. Great conversation, I can't wait to try out the 120 grit strop...

HH
 
Gizzard, Yes, it makes sense and yes, it always doesn't work out . But like science, it consists of a lot of testing and seldom arriving . How hard are we talking about ? So, then would it be possible to say, harden 440C to a higher RC thus now removing it from taking a good coarse edge ? An extreme example, whereas 58-59 is its best range . Knifenut, what is 'PM'(powder metalurgy) ? Me2, I agree . I've sharpened 425 in that manner and it does take the edge you describe . Heavy, Then, yes . I'd say once you go below 100grit your really pushing the envelope . But going extreme on either end is good as thats were somethings will surface that gives insight to the middle . But once you go to the 320g belt to sharpen, does that mean it (the edge) performs as a higher grit . Look is different than performance . Just last week I intentionally sharpened a older Buck knife w/ 440C blade one side of its edge on a 325g DMT and the other side on a 120g AO belt running at 600rpm . Then hand stropped it just enough to remove burrs . Now, looking at it I'm hard pressed to tell you which side is what grit and I was the one that did it . DM
 
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David Martin said:
Gizzard, Yes, it makes sense and yes, it always doesn't work out . But like science, it consists of a lot of testing and seldom arriving . How hard are we talking about ? So, then would it be possible to say, harden 440C to a higher RC thus now removing it from taking a good coarse edge ? An extreme example, whereas 58-59 is its best range . Knifenut, what is 'PM'(powder metalurgy) ? Me2, I agree . I've sharpened 425 in that manner and it does take the edge you describe . Heavy, Then, yes . I'd say once you go below 100grit your really pushing the envelope . But going extreme on either end is good as thats were somethings will surface that gives insight to the middle . But once you go to the 320g belt to sharpen, does that mean it (the edge) performs as a higher grit . Look is different than performance . Just last week I intentionally sharpened a older Buck knife w/ 440C blade one side of its edge on a 325g DMT and the other side on a 120g AO belt running at 600rpm . Then hand stropped it just enough to remove burrs . Now, looking at it I'm hard pressed to tell you which side is what grit and I was the one that did it . DM
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Correct.
 
HeavyHanded said:
To the best of my knowledge there's only two types of grinding media commonly available at under 100 grit, SiC and AO, with the later generally stuck to a belt. This really limits what can be done to test in this area, but how much larger a grit could you really go than the 60-80 range? If you're aware of any other materials I could be testing in this range, let me know! I know that belts come as large as 36 grit, but can one really hand sharpen on this? Once you put it on a belt, your results are going to be very different. A 320 grit power belt-sanded edge looks like a 1000 grit or better off a hand stone (IME).

HH
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I had an alox stone from congress tools that was 60 grit (the ruby line), it produced nice edges - www.congresstools.com Only reason I don't have it now is because I lost it :foot:

Also, there's the grinding wheels at the hardware store, just lay them on their sides and sharpen freehand, down to 24 grit :).

If you can only access belts/sandpaper, then use the scary sharp method of gluing it to glass.

One thing about the coarse grits is the friability of the abrasive, you will sharpen at a finer grit as it breaks down, so dress the stones and keep them clean of dust.

I think you guys may mean carbide instead of grain. Coarse grain steel is poorly heat treated, brittle, and can be any alloy that's been screwed up in thermal cycling.
 
I think you guys may mean carbide instead of grain. Coarse grain steel is poorly heat treated, brittle, and can be any alloy that's been screwed up in thermal cycling.
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Probably, I just don't know of any other way to put it. It sound better than "fine grain and those other steels"

So that begs the question, If 52100 and VG-10 are said to be "fine grain steels" what does that really mean compared to the others?
 
Dr. Verhoven speaks some of 440C being a large grain steel around 10 microns . Whereas, ATS-34 is 4 microns and the Sandvik steels lower . DM
 
Fine grain means higher than 5 on the scale, a steel like 52100 can do at least 9. It depends on temperature control and the number of times the steel is cycled. Do it too many times and you lose hardenability, but reducing grain size increases toughness. There are benefits to large grain for other uses - easier to machine, easier to deform, but for us that means weaker edges/blades.
 
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