Some knives just won't cut paper well after sharpening?

[yepimonfire]

I really don't think it's that my sharpening technique is flawed, otherwise I'd have the same problem on all my knives. I've got several knives that will cut paper, but not easily, they snag up. One is a Hampton forge chef knife, the rest of the knives in the set (santoku especially) cut pretty cleanly, all the same steel. Trailmaster snags but will cut, cs kukri machete won't cut paper at all, cs kudu....same as TM. All other knives cut easily, some go through paper like butter, even able to cut in an s pattern no snags, namely the hollow ground knives I own (kobun, ka bar mule). Some knives (mystery brand slicer kitchen knife) will still cut paper a little bit even when they're dull (but not totally blunt).

Just an issue with edge geometry or what? I'm fairly good at sharpening. The knives that snag in paper will still shave hair, not as easily as a razor but still do clean patches off my arm.

 

[Guest5160]

Check to see if any of the knives will cut paper when pulling towards you instead of slicing away. Do they shave in both directions? I'm no sharpening expert but, it sounds like you have a burr left behind.

 

[yepimonfire]

Check to see if any of the knives will cut paper when pulling towards you instead of slicing away. Do they shave in both directions? I'm no sharpening expert but, it sounds like you have a burr left behind.

Any idea how to remove it? I thought this too so I'd do light strokes on a super fine stone, sometimes alternating, that didn't work, sometimes ten light strokes on the other side of the side I just worked (where you'd expect a burr to be) etc.

 

[Obsessed with Edges]

I really don't think it's that my sharpening technique is flawed, otherwise I'd have the same problem on all my knives. I've got several knives that will cut paper, but not easily, they snag up. One is a Hampton forge chef knife, the rest of the knives in the set (santoku especially) cut pretty cleanly, all the same steel. Trailmaster snags but will cut, cs kukri machete won't cut paper at all, cs kudu....same as TM. All other knives cut easily, some go through paper like butter, even able to cut in an s pattern no snags, namely the hollow ground knives I own (kobun, ka bar mule). Some knives (mystery brand slicer kitchen knife) will still cut paper a little bit even when they're dull (but not totally blunt).

Just an issue with edge geometry or what? I'm fairly good at sharpening. The knives that snag in paper will still shave hair, not as easily as a razor but still do clean patches off my arm.

That's classic burr behavior. A burr is very thin and sharp, so it'll shave hair; but because it's very thin and therefore very weak, it folds over in anything tougher than hairs, so it snags. Will need to either use much lighter finishing strokes on the stones, or strop the edges with some compound that cleanly scrubs the burrs away. I like white rouge or other aluminum oxide compounds on very firm strops of denim or fabric for that (could also include polishing pastes like Flitz, Simichrome or Mother's Mag Aluminum and Wheel Polish).


David

 

[yepimonfire]

That's classic burr behavior. A burr is very thin and sharp, so it'll shave hair; but because it's very thin and therefore very weak, it folds over in anything tougher than hairs, so it snags. Will need to either use much lighter finishing strokes on the stones, or strop the edges with some compound that cleanly scrubs the burrs away. I like white rouge or other aluminum oxide compounds on very firm strops of denim or fabric for that (could also include polishing pastes like Flitz, Simichrome or Mother's Mag Aluminum and Wheel Polish).


David

What's the best way to go about this? One of the knives in question (kudu) just won't give up the burr, even with extremely light strokes alternating side to side, it improves sometimes, but still fails to perform. Seem to be having this issue with the chefs knife as well.

 

[Obsessed with Edges]

What's the best way to go about this? One of the knives in question (kudu) just won't give up the burr, even with extremely light strokes alternating side to side, it improves sometimes, but still fails to perform. Seem to be having this issue with the chefs knife as well.

That's pretty common with softish stainless, especially in kitchen knives. That's why I suggested the white rouge or other AlOx stropping on denim or linen, with very firm or hard backing behind it. It's the best thing I've seen for stripping burrs off of softish stainless and many other steels; it'll also refine the edge further. The firmer the backing is under the fabric, the crisper the apex of the edge will be. In the short term, if you don't have the materials together yet, you might also wrap some paper (single sheet, maybe two) around one of your stones, and strop on that. If you have a coarse or medium stone that sheds a little grit in use, you could collect some of that on the paper, and strop on that (again, wrapped around the stone). Full credit to member 'HeavyHanded' (Martin) for that technique; it can work very well on such knives. :thumbup:


David

 

[yepimonfire]

Still having this problem with trailmaster too. What I've tried so far is feather light strokes alternating on 8000 grit stone, making a slicing motion through wood with the edge, straight up and down and at an angle, also tried an eraser, still having problems, seems to improve somewhat but still snagging. Is stropping necessary? Any compound I got would probably be marginally finer then the 8000 grit stone. The edge is mirror polished off it.

 

[yepimonfire]

http://www.amazon.com/JacksonLea-47...11669807&sr=8-4&keywords=White+rouge+compound

This the stuff? Also does it need to be denim or can I use leather to strop? Is it possible the burr may just be moved around during stropping or will this cut it off for good?

 

[Obsessed with Edges]

http://www.amazon.com/JacksonLea-47...11669807&sr=8-4&keywords=White+rouge+compound

This the stuff? Also does it need to be denim or can I use leather to strop? Is it possible the burr may just be moved around during stropping or will this cut it off for good?

That's listed as working for stainless steel, so it'll probably do. There are a lot of aluminum-oxide 'white' compounds out there, from many different sources. I've liked the Ryobi white rouge I picked up at Home Depot a few years ago (though the same formulation may not be available now), and recently I've also been using some grey aluminum oxide compound I found at Sears (it's their '#2' compound described for 'regular cleaning' of stainless steel and other metals). Seems to strip burrs as effectively as the Ryobi, and finishes just a hair coarser, I think, with a little more bite in the edge. That's actually what I've been using on the denim lately, and the Ryobi white rouge I'd used on some linen from an old shirt (over wood). I'd previously tried the white rouge on leather, but the thinner denim or linen really seems to hold the compound better, and it works much more aggressively on the fabric over firm/hard wood backing, than on the leather. In fact, I'd never found such an effective way to strip burrs while using leather at all, without also rounding off the apex.


David

 

[yepimonfire]

That's listed as working for stainless steel, so it'll probably do. There are a lot of aluminum-oxide 'white' compounds out there, from many different sources. I've liked the Ryobi white rouge I picked up at Home Depot a few years ago (though the same formulation may not be available now), and recently I've also been using some grey aluminum oxide compound I found at Sears (it's their '#2' compound described for 'regular cleaning' of stainless steel and other metals). Seems to strip burrs as effectively as the Ryobi, and finishes just a hair coarser, I think, with a little more bite in the edge. That's actually what I've been using on the denim lately, and the Ryobi white rouge I'd used on some linen from an old shirt (over wood). I'd previously tried the white rouge on leather, but the thinner denim or linen really seems to hold the compound better, and it works much more aggressively on the fabric over firm/hard wood backing, than on the leather. In fact, I'd never found such an effective way to strip burrs while using leather at all, without also rounding off the apex.


David

Thanks. Ordered some and will wrap my stone in denim, will report back if I'm still having problems.

 

[Guest5160]

On such a high grit stone, you may get away with just doing some very very light edge trailing strokes on the stone at a slightly more obtuse angle than the bevel.

Again, no expert but this may hold you over until your stropping supplies arrive. This method is sufficient for my needs in most cases. FWIW, my Kudu also had an impossible burr. Stropping on the sharpmaker white stones knocked it off.

 

[yepimonfire]

That's listed as working for stainless steel, so it'll probably do. There are a lot of aluminum-oxide 'white' compounds out there, from many different sources. I've liked the Ryobi white rouge I picked up at Home Depot a few years ago (though the same formulation may not be available now), and recently I've also been using some grey aluminum oxide compound I found at Sears (it's their '#2' compound described for 'regular cleaning' of stainless steel and other metals). Seems to strip burrs as effectively as the Ryobi, and finishes just a hair coarser, I think, with a little more bite in the edge. That's actually what I've been using on the denim lately, and the Ryobi white rouge I'd used on some linen from an old shirt (over wood). I'd previously tried the white rouge on leather, but the thinner denim or linen really seems to hold the compound better, and it works much more aggressively on the fabric over firm/hard wood backing, than on the leather. In fact, I'd never found such an effective way to strip burrs while using leather at all, without also rounding off the apex.


David

Thanks. Ordered some and will wrap my stone in denim, will report back if I'm still having problems.

 

[Obsessed with Edges]

Still having this problem with trailmaster too. What I've tried so far is feather light strokes alternating on 8000 grit stone, making a slicing motion through wood with the edge, straight up and down and at an angle, also tried an eraser, still having problems, seems to improve somewhat but still snagging. Is stropping necessary? Any compound I got would probably be marginally finer then the 8000 grit stone. The edge is mirror polished off it.

I'd missed this earlier. I'd treat it the same way; still recommend stropping as I'd suggested for the others, with the white compound or similar on fabric. It's almost bullet-proof in it's effectiveness with burrs. Drawing the edge through wood won't work so well with ductile steels, as the burrs often won't break away, but instead need to be gently abraded (filed) off; that's what the recommended stropping method does very, very well.


David

 

[me2]

For stubborn burrs, raise the angle significantly, like double, then alternate passes on a medium grit like Norton Fine India. It should only take 2 or 3 per side. You can then progress through finer stones. If this doesnt do it, cut off the edge into the stone and try again. There may be some damaged material at the edge, which this will remove.

 

[yepimonfire]

I'd missed this earlier. I'd treat it the same way; still recommend stropping as I'd suggested for the others, with the white compound or similar on fabric. It's almost bullet-proof in it's effectiveness with burrs. Drawing the edge through wood won't work so well with ductile steels, as the burrs often won't break away, but instead need to be gently abraded (filed) off; that's what the recommended stropping method does very, very well.


David

Is SK-5 a ductile steel? I'd figure it wouldn't be, softer kitchen and kudu makes sense. I've also noticed I've never ever had stubborn burr issues on AUS 8a or 8cr13moV (almost identical steels). Other carbon steels? So far my main issue has been sk5, 1055 (which is obviously ductile) and whatever mystery carbon steel gerber uses on their gator machetes.

 

[Obsessed with Edges]

Is SK-5 a ductile steel? I'd figure it wouldn't be, softer kitchen and kudu makes sense. I've also noticed I've never ever had stubborn burr issues on AUS 8a or 8cr13moV (almost identical steels). Other carbon steels? So far my main issue has been sk5, 1055 (which is obviously ductile) and whatever mystery carbon steel gerber uses on their gator machetes.

A lot of steels can be 'ductile', depending on hardness of the individual blade. One of the interesting ones I've seen is VG-10, which can be tenaciously ductile at somewhat lower hardness (Spyderco's VG-10, for example), with very stubborn burrs, but much less so at higher hardness, where burrs present little problems at all. Another example is with 420HC, which forms very tenacious burrs at mid-50s HRC, but they come off much more easily at HRC ~58 or so. Same could be said for 1095 and many other steels.

Some proof of the ductility is in the behavior of the burrs, with the more ductile ones hanging on stubbornly and refusing to break off, such as what you're seeing in these knives.


David

 

[yepimonfire]

For stubborn burrs, raise the angle significantly, like double, then alternate passes on a medium grit like Norton Fine India. It should only take 2 or 3 per side. You can then progress through finer stones. If this doesnt do it, cut off the edge into the stone and try again. There may be some damaged material at the edge, which this will remove.

I tried doing this to no avail.

 

[n7titan]

If you can, post pictures with a magnifying glass or loupe. It would help a lot with suggestions.

 

[yepimonfire]

Don't have one, I suppose I can try a magnifying glass tomorrow but rest assured, after some very careful examination I can see a burr when the light hits the edge just right, it's extremely small but there.

So far I have goofed around with it on the stones all day, even cut the edge off with a stone and re sharpened it using much lighter strokes, finishing with the high grit using alternate strokes, raised the angle by 5-10 degrees using either a medium grit or the high grit for 3-5 swipes. The damn thing just doesn't budge, and if I do manage to get rid of the burr raising the angle (I have no clue if it does, or if I just make another burred microbevel) it comes right back after returning the previous angle on a fine stone with very few light swipes.

Also tried a slow cutting arkansas to finish it instead of my fast cutting water stone, made no difference. The same thing happens on the trailmaster as well as the kitchen knife, though I didn't screw with the TM as much because I didn't want to waste the steel on my favorite knife.

 

[n7titan]

Don't have one, I suppose I can try a magnifying glass tomorrow but rest assured, after some very careful examination I can see a burr when the light hits the edge just right, it's extremely small but there.

So far I have goofed around with it on the stones all day, even cut the edge off with a stone and re sharpened it using much lighter strokes, finishing with the high grit using alternate strokes, raised the angle by 5-10 degrees using either a medium grit or the high grit for 3-5 swipes. The damn thing just doesn't budge, and if I do manage to get rid of the burr raising the angle (I have no clue if it does, or if I just make another burred microbevel) it comes right back after returning the previous angle on a fine stone with very few light swipes.

Also tried a slow cutting arkansas to finish it instead of my fast cutting water stone, made no difference. The same thing happens on the trailmaster as well as the kitchen knife, though I didn't screw with the TM as much because I didn't want to waste the steel on my favorite knife.

In that case a video of you trying would probably be the best way to get help. Maybe you're making a mistake somewhere but you yourself didn't realize it so you can't describe it to us. Hard to say.