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

[HeavyHanded]

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.

Sometimes alternating light draws across the wood with some stone work can get stubborn burrs to give up. You have make sure when you are working it that the burr is flipping (or disappearing). My favorite is used by a number of folk on the forum - ID which side the burr is on and scrape the edge at a 90* angle across the corner of a bench (wood) or along a dowel etc, the idea is to make it lean over further. Going back to the stones for a few light leading passes it is less likely to flop under pressure.

 

[me2]

Are you forming a burr intentionally when sharpening?

 

[mrdeus]

A method I use to get rid of stubborn or big burrs is one that Bluntcut suggested once upon a time: to fold the burr over to one side by scraping the edge against a piece of wood, then doing light edge leading strokes with the burr facing down towards the stone (pinching it off), then fold the burr to the other side and confirm it's still there and do the same thing on the other side of the blade.

 

[BluntCut MetalWorks]

Thanks mrdeus!

I use this technique almost every time I sharpen knives. It's a good method to confirm that the apex is strong and mostly burr/wire free (except for possibly a tiny amount newly generated by cut-it-off via edge leading stroke). Here is a video I made while ago: http://youtu.be/l2ynSDYEUYI

A method I use to get rid of stubborn or big burrs is one that Bluntcut suggested once upon a time: to fold the burr over to one side by scraping the edge against a piece of wood, then doing light edge leading strokes with the burr facing down towards the stone (pinching it off), then fold the burr to the other side and confirm it's still there and do the same thing on the other side of the blade.

 

[yepimonfire]

Denim strop has solved the issue on all knives minus the kitchen, this one is much improved though and I was in a hurry, will strop more later.

 

[Obsessed with Edges]

Denim strop has solved the issue on all knives minus the kitchen, this one is much improved though and I was in a hurry, will strop more later.

That's good to hear. :thumbup:

What brand/make/steel is the kitchen knife? Assuming typical kitchen cutlery in stainless, some of those can leave some thick burrs, but the steel is still soft & easy to abrade. Might just need a little more refinement work, either on stones or additionally on the denim strop. If the compound you're using is similar to the white/grey I've used, it'll still likely get it done.


David

 

[yepimonfire]

Hampton forge continental. Mystery steel, but they take nice edges for a cheap kitchen knife.

 

[Obsessed with Edges]

Hampton forge continental. Mystery steel, but they take nice edges for a cheap kitchen knife.

Sounds about right, as compared to the 'inexpensive' kitchen knives I've got. I have some inexpensive, older Japanese-made 'Barclay Forge' kitchen knives that could match that description.

I suspect just a little more work with stones and/or strop should take care of it. Sometimes, with knives like these, I focus more on cleaning up the burrs as much as possible on the stone; and they seem to take the best working edges from a relatively coarse stone, like ~320 or so (I like the 'Fine' side of the inexpensive 'Norton Economy' SiC stone for this, found at Home Depot). I think I suggested using some paper wrapped around your stone earlier, as a 'strop'. Leaves almost all of the the 320-grit bite on the edge, and will knock of the worst of the burrs. That's often how I've maintained the edge on my Barclay Forge paring knife.


David

 

[yepimonfire]

With or without compound? Off the 8k waterstone all of the knives will push cut tomatoes, so never needed to leave it toothy.

 

[Obsessed with Edges]

With or without compound? Off the 8k waterstone all of the knives will push cut tomatoes, so never needed to leave it toothy.

Either way. As I'd mentioned earlier, member HeavyHanded had suggested the paper wrapped around the stone, sometimes using compound, or loose grit shed from the stone itself, or just the bare paper. The hard stone backing under the paper is what provides most of the 'oomph' in scrubbing burrs off, without significantly altering or polishing the bevels themselves. If you're getting good results with your 8k waterstone on this knife, you may not need to worry about that anyway.


David

 

[yepimonfire]

I have still failed to remove the burr from the chefs knife. I've tried the paper wrapped stone idea too. The edge also now has several tiny chips from attempted paper slices. Perhaps I should change the angle from 20° to 25°? Beginning to wonder if the edge itself is the problem and not a burr being stubborn. Steel maybe too soft.

 

[yepimonfire]

I've also noticed when it first comes off the strop, I run my finger over the edge and it feels insanely sharp, no raggedness, I can't see a burr, but it starts degrading, chipping or folding when cutting anything but my skin.

 

[Obsessed with Edges]

I have still failed to remove the burr from the chefs knife. I've tried the paper wrapped stone idea too. The edge also now has several tiny chips from attempted paper slices. Perhaps I should change the angle from 20° to 25°? Beginning to wonder if the edge itself is the problem and not a burr being stubborn. Steel maybe too soft.

I've also noticed when it first comes off the strop, I run my finger over the edge and it feels insanely sharp, no raggedness, I can't see a burr, but it starts degrading, chipping or folding when cutting anything but my skin.

Is that the inclusive angle, or per side? If inclusive at 20° (10°/side), that very well could be too thin for the steel. If the steel's too soft, more likely it's just denting/deforming, as opposed to actually chipping (bits fracturing out). I have a 'Chicago Cutlery' kitchen utility knife (bought at Walmart for ~ $8 or so, of Chinese manufacture) that behaved like that, when I took the edge too thin. Took a very, very fine edge, but it'd fold or dent almost immediately in use.


David

 

[yepimonfire]

No it's per side I'm almost sure. Whatever edge the chefs choice i used to use put on it (which iirc is 20 per side).

 

[Obsessed with Edges]

No it's per side I'm almost sure. Whatever edge the chefs choice i used to use put on it (which iirc is 20 per side).

Still sounds like the steel is veerrry soft, if it's degrading so fast in use. After stropping on the denim, what are you doing to test the cutting? I'm curious to hear how it cuts in something like phonebook paper. If burrs are the issue, it'll snag that paper a LOT in cutting it; if the steel's too delicate for other tasks, it should at least slice cleanly through a piece of the phonebook paper. Even my 'softest' steel blades will manage that, but then degrade quickly in doing much else (like kitchen tasks with veggies or whatever).


David

 

[yepimonfire]

It snags. Considering there's a burr and its probably really soft, could increasing the angle reduce the likelihood that an in curable burr shows up?

 

[yepimonfire]

Also must be noted, I have hit most all my knives today with my new makeshift strop and have achieved levels of sharpness that I didn't even realize existed, all knives including big bowies are carving paper like butter. I'm wondering if the kitchen knives are a lost cause and just awful steel to work with. Tried the strop on my slicer and same results.

 

[kelbro]

Also must be noted, I have hit most all my knives today with my new makeshift strop and have achieved levels of sharpness that I didn't even realize existed, all knives including big bowies are carving paper like butter. I'm wondering if the kitchen knives are a lost cause and just awful steel to work with. Tried the strop on my slicer and same results.

I have tossed some kitchen knives for this very reason. There is only so much time and it's not worth wasting on lousy steel knives.

 

[calc]

Are you forming a burr intentionally when sharpening?

On that note, burr management can be quite a bit easier if one doesn't form a large one to begin with - once I stopped raising such a large burr, my process got much more efficient.

 

[Obsessed with Edges]

It snags. Considering there's a burr and its probably really soft, could increasing the angle reduce the likelihood that an in curable burr shows up?

Also must be noted, I have hit most all my knives today with my new makeshift strop and have achieved levels of sharpness that I didn't even realize existed, all knives including big bowies are carving paper like butter. I'm wondering if the kitchen knives are a lost cause and just awful steel to work with. Tried the strop on my slicer and same results.

The only thing I've ever seen that minimizes burrs on soft steels, is going ultra-light in pressure used, in all sharpening stages, including stropping. Even at wider edge angles, the same tenacious burrs will still form when the apex is reached, if pressure hasn't been reduced. With a blade like this one, that could mean having to modify habits that you ordinarily wouldn't have to, like altering the way you hold the knife in order to decrease the force exerted on the blade. I'd still suggest trying a finish that's coarser & toothier, as opposed to the 8k finish you'd mentioned earlier. The delicate nature of the edge, as you've described it, is the same behavior I used to notice in kitchen knives I tried to take that high in finish; they'd 'test' well in things like popping hairs, but the fine edge would fold under any other use. The steel will still be just as 'soft' with a ~320-grit finish, but the tooth in the edge will at least make the knife a bit more useful before it goes dull again. As you've asked, increasing the edge angle could also help somewhat, in tandem with a coarser edge finish.


David