I started using a belt sander to sharpen my knives and have been happy with the edges I've gotten so far. I still can't get them to cut hair without touching skin but they will shave and easily slice paper. Now I don't believe my problem is not removing the burr as I am very careful about it. I remove on soft wood, then cork, then surgi-sharp belt with veritas compound. I check my edges and looking straight down at them they reflect no light and slight angles no glints either. Then I use them in the kitchen for veggie slicing. When I'm done and look at the edge under light I can see very slight little glints in random areas along the edge when held at slight angles. Can't see any looking straight down. Usually close to the front third of the edge as I use that area the most. The edges are still very sharp and still shave and easily cut thin paper. Are those tiny glints normal? Is that just the slight wear as it's no longer "fresh off the strop"? I tried batoning for the first time to see what it was about with a Mora #1 after given the same treatment and after a bit of pounding the edge into wood and twisting it was still very sharp when i was done so the edges seem to be holding up but I've only been sharpening like this for the last couple weeks so don't really know the edge holding yet of my sharpening. Also watching cooking shows I realize my knives still aren't super sharp yet as i can't quickly push cut my knives through material like they can. They just seem to dice and food falls apart. I still need to slice to cut my food. And I finish at 9u before stropping with compound and my edges are mirrors.
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edge problems
- Thread starter Vicv
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BluntCut MetalWorks
Knifemaker / Craftsman / Service Provider
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sound like a wire edge problem.
diagnose: trailing stroke on leather or balsa, rest at start at 0 degree, raise the angle to 90 along with the stroke. now look at the edge, wire/long-burrs should glint in light.
solution: deburr (lots of posts on this). For persistent acute angle burrs, I use edge leading-stroke into a dmt xxf diafold.
diagnose: trailing stroke on leather or balsa, rest at start at 0 degree, raise the angle to 90 along with the stroke. now look at the edge, wire/long-burrs should glint in light.
solution: deburr (lots of posts on this). For persistent acute angle burrs, I use edge leading-stroke into a dmt xxf diafold.
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It does sound like you might have just a tiny burr remaining on that edge. Also, what kind of cutting board do you have? It could also be impaction or rolling caused by the cutting board surface, or the way your knife is going into the board.
As for the pros, bear in mind that the whole blade's geometry plays into how those cut. Thickness, main grind and the edge, surface finish and technique also play HUGE parts in how the knife cuts. The edge is critical, but when you're following a process like that, it's by no means the ONLY thing that matters.
As for the pros, bear in mind that the whole blade's geometry plays into how those cut. Thickness, main grind and the edge, surface finish and technique also play HUGE parts in how the knife cuts. The edge is critical, but when you're following a process like that, it's by no means the ONLY thing that matters.
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^ this
I check for wire edges by very lightly backdragging the apex along a hardwood dowel at close to 90 degrees. If I can do this two or three times and not see anything fold over into the light I know I'm good.
Part of the issue with cutting might be your apex is more obtuse than you think it is - easy to make it too broad on a slack belt or on sandpaper over a mouse pad etc.
FWIW they sound fairly sharp anyway.
Wouldn't having too obtuse an apex cause the edge to last longer? I use a thick maple board only. I really thought burr was gone. 90o through wood. Then a Terri towel. Then cork. Then leather belt and I even increase angle a tad. I can't feel or see any burr. I usually hold the spine about 90o to floor on the grinder. The belt has a slight angle inward as the top pully is back a bit from the platen. From my bevel height I'd say I'm keeping the angle between 10 to 20 degrees and as its convex I'd heard it's ok to go a bit shallower
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10 to 20 degrees per side? If per side, that's extremely thin at 10 degrees (20 inclusive), and could easily roll/dent/chip after light use on a cutting board. At 20 per side (40 inclusive), that could be challenging to make it shave consistently, unless the apex is perfect. And convexing usually makes the very edge angle a bit thicker, on top of that.
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The little 'glints' on the edge you spoke of, after using your knife on your cutting board, might be an indication of the edge being a bit too thin, OR a burr/wire as mentioned. I have an Opinel that I sanded down to a very, very thin edge. It's a fantastic slicer, but it behaves similarly if cutting against a firm or hard backing, like a cutting board. Very easy to roll/dent the edge on it.
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Ya angle is hard to determine with a convex because of the belt bending. On one knife is a wustof 8" chef. Not my best or favorite but a decent workhorse. When I got it I figure was about 22o a side. So re ground it by hand about double the height on the blade. That edge lasted quite a long time. On the belt sander I kept the same height so I figure around 30o inclusive which isn't that acute. It must still be burrs. I just can't think of anything else to do to remove them. After 9u it should just wipe off its so small and fine. I use the cork till there's no black colour in the cut. Then strop
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Most kitchen knives, especially stainless ones like Wusthof (I have one), are relatively low hardness (mid 50s), and at the same time, also very ductile. This means it can be extremely challenging at times, to break burrs/wires off the edges. They tend to just keep bending back & forth, but don't come off easily. My preference, with knives like these, is to very gently abrade the wire edges away. I usually do it with a medium/fine ceramic hone, with edge-leading strokes at an elevated angle, and very, very light pressure. The earlier suggestion of doing the same with a very fine diamond hone should work too.
There's also a possibility that if you're not sure about the exact angle, and might also be having some variability in holding an exact angle, the edge could be rounded a little too much. This could account for the difficulty in making the blade shave hair consistently. Stropping usually just makes the rounded edge even smoother, which just makes the cutting worse. To me, the possibility of inconsistent angle control is what I'd focus on first. That's basically the foundation of everything, and anything else following that won't help, if the angle isn't tightly controlled during initial grinding.
Ya. Angle control is even harder than bench stones by far cause you have nothing to rest it on. My grind lines are pretty even though. Mayby I'll try using my lansky with the 1000 grit stone at the 25o setting and a few very light passes per Side to completely remove wire. Could the leather with compound be making a minuscule burr. It is .5u so it does remove metal
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All the better, that's a good idea. Using the guide with the Lansky setup can help pinpoint if angle control is the main issue here. It's how I first learned the true importance of angle control. Never realized the difference it made, until doing that for the first time. Even a small micro bevel created with it can make a big difference in cutting.
I wouldn't worry too much, about your 0.5 micron compound creating any significant burrs. More than likely, it should help diminish any that are left.
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I ultimately decided belt sander sharpening wasn't for me due to the difficulty in removing burrs. Even with a cork belt and compound I wasn't sure how thorough a job I was doing. Edge trailing at that speed its easy to have a wire edge with a very smooth transition - basically invisible. That's when I started doing the scrape test to check for wire edges and burrs. Too many of my belt sander and edge trailing sandpaper edges failed this test.
The observation re kitchen knives and the softer steel is dead-on. You might be doing everything fine and the edge just doesn't want to hold up, tho at 30 inclusive it should cut well for some time.
I've found that stropping on newspaper as a final treatment will frequently expose the smallest of burrs.
The observation re kitchen knives and the softer steel is dead-on. You might be doing everything fine and the edge just doesn't want to hold up, tho at 30 inclusive it should cut well for some time.
I've found that stropping on newspaper as a final treatment will frequently expose the smallest of burrs.
This is a very interesting thread, as I did have this issue with a yojmbo 2 a couple of months ago. How I got rid of the burr was through running it a couple of times at a more obtuse angle to put a micro bevel. That seemed to do the trick.
I ask now, would I have benefitied if I just kept stropping? Would that deburr the edge?
I ask now, would I have benefitied if I just kept stropping? Would that deburr the edge?
I dunno, I've once or twice had a tendency to overdo it and wound up rolling over the apex. I've tried deburring with wood and corks before too, but generally found it either didn't get the burr off, or once it did it wasn't that sharp and required stropping--which then if you're like me, you usually wind up messing up when stropping that much. Kind of a vicious cycle...
Your idea with the edge-leading at light pressure is the only thing that works to get burrs off for me. I usually do something like five passes a side at light pressure, three per side at very light pressure, and then alternate side to side with barely any pressure at all ( once heard someone describe this as "kissing the stone") and continue this until it's satisfactory. I mostly focus on the pressure, going from light to get the burr off, to ultra-light to refine the edge without raising another. This just tends to chew up any wire that's on there, and on the odd occasion I've been able to catch it in the right light it's very cool to watch the wire gradually turn up, and then disappear into the swarf.
I think I tend to form a wire because I use a lot of back-and-forth motion on waterstones when initially profiling. It would frustrate me a lot when I would think the knife was burr free, go and strop, cut something and see glinting. Strop it again and think, "Okay, the wire is gone," but really it had just been set up straight, and would just come right back. Only thing that seems to work is abrading it away from the top down, and that means edge-leading. Afterward stropping works pretty good to refine, but without getting the burr/wire off beforehand it never did much for that cause.
I could go on and speculate why I think edge-leading is important, and why to use light pressure... But I don't really know from theory, I just know it's been working for me. I think maybe one thing that tends to happen with edge-leading that makes burr removal this way seem worse is that the pressure control is very essential. They say edge-trailing can draw and stretch a wire edge out, but I've also seen it said that edge-leading with too much pressure can actually bend the wire and part of the edge apex over, leading to you chasing a constant burr or blunting the apex.
Anyway, just my $.02, YMMV and all that.
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I'd say, with some steels yes, and others, probably not. Burrs and wires on steels like 420HC (similar to many kitchen knives), VG-10 and ATS-34 will simply laugh diabolically at most strops, from what I've seen. Those are always the ones that get the edge-leading, elevated angle, ceramic hone treatment, in my case. On the other hand, stropping usually works quickly on simple carbon steels like 1095, in cleaning up burrs. D2 also seems to respond well on a strop, if the edge is truly refined prior.
Thanks for your response, from your name I think I can take your word/expirience on things
. Would stropping work on higher end steels like CPM 154 ,M4, and Vanax? (a lot of my knives are these steels and I hate to keep sharpening /grinding thier lives away..hence my micro bevel "solution"
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Thanks for your response, from your name I think I can take your word/expirience on things
Would stropping work on higher end steels like CPM 154 ,M4, and Vanax? (a lot of my knives are these steels and I hate to keep sharpening /grinding thier lives away..hence my micro bevel "solution"
To be honest, I don't know how they'd respond. Haven't tried them yet. I'm sure others here have, and I'd bet at the very least, there should be certain combinations of strops & compounds that might be ideal for them. If they're like many other of the 'super steels', I'd think diamond or CBN, or silicon carbide at least, might work for those. Hopefully others will chime in on this...
CBN? Also, just to make sure that im understanding correctly, a silicone carbide paste exists?? Iv heard of diamond paste (never tried it though to be honest) but this is my frist time hearing of silicone carbide
Edges are a beautiful thing, hopefully someone chimes in and I can learn how to keep em!
This burr thing is a pain. I hear you about giving up on the belt sander. It's so fast and effective though! The lansky thing didnt work though. Even a couple very light stokes with the ceramic hone created a micro bevel which was too obtuse and dulled it. I'll try my 6000 king next. These burrs are persistent. And yes the softer stainlesses seem worse. My custom o1 was easy ro remove the burr and it's the sharpest I've gotten yet. On the other hand I have an unknown carbon Chinese chef knife that is also being stubborn. Not to mention a 3.5" wide blade is very difficult to keep the angle correct!
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CBN = Cubic Boron Nitride, it's hardness is second only to diamond, apparently.
Not sure if there's any pre-made silicon carbide pastes out there. However, there are a LOT of silicon carbide powders available, which I'm sure could be mixed with mineral oil or something similar. If you search in posts by member HeavyHanded (he posted earlier in this thread), he's used 'em quite a lot and posted some very informative feedback about it.
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I'm wondering, if the micro bevel created on the Lansky was too obtuse, it makes me wonder what the angle of the original edge is. The nature of a micro bevel is, it always must be wider than the primary edge you put it on. That being the case, the original edge angle might be rather obtuse itself, maybe as a result of possible rounding mentioned earlier. I'd still be focusing on making absolutely sure the edge angle is consistent and hopefully within a 30 degree inclusive limit (15 per side; usually a good all-around edge).