burrs on different steels

E

elementfe

Joined
May 3, 2008
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In order to have a knife-related income stream, I've started sharpening in addition to selling simple kitchen knives at our farmers market.
All I can say is, Wow, what an education in different steels!

My question is, there are some steels that pull a burr when you look at them wrong and it's next to impossible to get rid of it. The paper wheel with white rouge won't even get it off...I often strop on a bench strop with green chrome (the Jantz version, which is pretty fine) and very lightly slice the edge of the strop, which works on decent steel but wow, those stubborn burrs on some knives...
My usual progression for heavily used, usually inexpensive, kitchen knives is, 100 grit very lightly, then 100 micron, 16 micron, 5 micron (all on the 1x30) and finish on the strop.

Any good tricks for getting that last bit of burr off a cheap knife? I hate to give it back without a clean edge.
Thanks,
Andy G.
 
Destress and remove the burr by lightly cutting into the stone a couple times , reapexed from there, it won't take much and the edge will be stronger as you removed the weekend metal from flipping the burr
 
OK, I hadn't tried that- is it better to cut into wood than into leather, will that remove a stubborn burr better than leather?
 
Yes, wood is better than leather. I have a short piece of pine 1X4 that I use on small stubborn burrs. If you are using the paper wheels, try to remove as much of the burr as you can by very lightly grinding the burr side a small amount to lessen the size of the burr. Then run the edge thru the end of a piece of wood and then use the slotted wheel to strop the edge with. That should get the knife sharper than most people have ever had their knives done before. You really should not need the leather strop, as the slight toothy edge left will work better with kitchen knives than a highly polished edge. Of course if you are doing folders and pocket knives, then you might want to use the strop for "show".

In reality, My knives that come off the slotted wheel are sharper than when I strop them on a leather strop. (my fault I am sure, as my stropping is less than perfect with a standard strop.) I tend to use too much pressure and take too many strokes and wind up rounding the apex of my knives. The exception is my carving knives which I use flexcut gold compound impregnated into a very thin leather strop to sharpen and maintain them without any grinding to them at all.

When stropping the knives on the paper wheel, start with the burr side first and then go to the other side. It seems to work better for me than way.

Blessings,

Omar
 
Thanks- is the slotted wheel the coarse or finish wheel? Someone gave me a set and I'm wondering if it was set up properly.
I'm wondering about the physics of sharpening "average" kitchen knives...it seems that a fine, polished edge may be too thin (seen through a microscope) to stand up to "average" use, though perhaps changing the final bevel angle would address that.
 
For cheap knives you are going to fine in the grit scale, stop around 100 grit then deburr. A 5 Micron edge on "surgical steel" will fail quickly and is not worth the time you spent applying it.
 
Knifenut, would you care to talk about why that 5m edge would fail?
Wouldn't it benefit from having a polished edge, if the bevel is adjusted to the steel's hardness/toughness?
I know these are pretty elementary questions, I'm like a sponge right now trying to learn as much as I can!
 
elementfe said:
Thanks- is the slotted wheel the coarse or finish wheel? Someone gave me a set and I'm wondering if it was set up properly.
I'm wondering about the physics of sharpening "average" kitchen knives...it seems that a fine, polished edge may be too thin (seen through a microscope) to stand up to "average" use, though perhaps changing the final bevel angle would address that.
Click to expand...

The slotted wheel is the one with the slots in it that you put the white "rouge" on. It should be black and smooth from the steel being stropped on it. The grinding wheel is the one with the grit on it. The grit is 180 grit, and should have some wax imbedded into it to absorb the heat from grinding the blade, and prohibit the blade from getting too hot and ruining the heat treat of the blade. See the stickie at the top of this forum about the paper wheels. All you ever wanted to know about them but were afraid to ask is in that stickie, by Richard J. They are ideal for what you are doing. I have a small side business sharpening knives, and the Paper wheels are what I use exclusively in that business. I have a set of diamond plates that I am experimenting with, but so far they will not replace my paper wheels. I can sharpen a kitchen knife in about 5 minutes with the wheels, which is what you need at a Farmer's Market setting. Good luck in your endeavor.

Blessings,

Omar
 
It's a little factor called edge stability and it relates to steel hardness. When a steel is very hard (60+ hrc) it has the ability to resist deformation and thus can be taken to a very fine edge and hold it, when a steel is softer like most cheap stainless knives and German knives it can be damaged easily which makes a finer edge more prone to damage.
 
knifenut1013 said:
It's a little factor called edge stability and it relates to steel hardness. When a steel is very hard (60+ hrc) it has the ability to resist deformation and thus can be taken to a very fine edge and hold it, when a steel is softer like most cheap stainless knives and German knives it can be damaged easily which makes a finer edge more prone to damage.
Click to expand...

Are German knives soft? This is not what I would have expected. When I say German, Heinkel comes to mind. I have one, that hasn't "appeared" soft to me. What then, would you reccomend as a sharpening routine on it? Thanks for the info.
 
L2bravo said:
Are German knives soft? This is not what I would have expected. When I say German, Heinkel comes to mind. I have one, that hasn't "appeared" soft to me. What then, would you reccomend as a sharpening routine on it? Thanks for the info.
Click to expand...

All German knives such as henckles are made of X50crmov15 stainless steel with a hardness of about 56-57. Not very ard for a kitchen knife. As for sharpening coarser edges help, a Norton India or around 1k waterstone does well.
 
Yes, they use better steel too. Very big performance difference with even a basic Japanese knife.
 
elementfe said:
In order to have a knife-related income stream, I've started sharpening in addition to selling simple kitchen knives at our farmers market.
All I can say is, Wow, what an education in different steels!

My question is, there are some steels that pull a burr when you look at them wrong and it's next to impossible to get rid of it. The paper wheel with white rouge won't even get it off...I often strop on a bench strop with green chrome (the Jantz version, which is pretty fine) and very lightly slice the edge of the strop, which works on decent steel but wow, those stubborn burrs on some knives...
My usual progression for heavily used, usually inexpensive, kitchen knives is, 100 grit very lightly, then 100 micron, 16 micron, 5 micron (all on the 1x30) and finish on the strop.

Any good tricks for getting that last bit of burr off a cheap knife? I hate to give it back without a clean edge.
Thanks,
Andy G.
Click to expand...

My opinion - your biggest issue is that all your grinding and finishing are edge trailing. Even at speed on a powered belt, you'll have a tough time cleanly removing the last bit of unsupported steel from softer metals without using a few edge leading strokes on a stone, or maybe on the stationary belt depending on the set-up. Stubborn burrs can be helped by back-dragging the edge along a piece of wood at a steep angle to make them stand extra tall, and sweep them off with a few light, edge-leading passes. Per the above sentiments, I wouldn't think going higher than the 16u will be worth the time.
 
Thanks, Heavy-
It's pretty easy to run through grits with a quick change belt setup, but there's got to be a point of diminishing returns.
What's your take, is there anything to the "toothy edge is better for slicing" theory?
Andy
 
elementfe said:
Thanks, Heavy-
It's pretty easy to run through grits with a quick change belt setup, but there's got to be a point of diminishing returns.
What's your take, is there anything to the "toothy edge is better for slicing" theory?
Andy
Click to expand...


Absolutely. My whole theory is that you should make the edge that's best for the task (or user). A coarse edge will hold up to the most abuse and still work - might not be pretty. So a good choice for heavy slicing jobs, jobs where abuse is a necessary evil, for people that aren't likely to use their knife with care - I go for about a 320 grit. At 600-800 is where it will work best across a range of uses - apex is small enough across that it can chop well, yet there's enough variation in the line for it to draw/slice well. At 1500 and up the edge is best used mostly for chopping, shaving, fine carving etc.

I've also speculated that a coarse edge will last longer if used for draw cutting, and a fine edge last longer if used for chopping/shaving. Have had several recent experiences with hatchets and machetes taken to fairly high polish and they held that edge for a long time - consider these tools have relatively low RC and plain steels. Have had edges done up on an 80 grit stone last for a month or more at work cutting clay-coated cover weight paper (board) where a finer polish utterly failed within days under the same usage.

Softer Western kitchen cutlery taken above 600 grit needs to be babied in use or it will dull very fast. Also requires more pampering just to get it there cleanly, as you've already discovered. As many others on the forum have advocated, I get great results on my cheap kitchen knives just using the underside of a coffee cup. These are inexpensive Chinese stainless that get tossed in unceremoniously in a drawer, and occasionally used on plates and countertops! The coffee cup/mixing bowl method doesn't work so well on my Japanese stainless set - only I get to use these, and I maintain them on my Washboard, or before that on my jointer stones or waterstones. Even still, the rough-use gets an approximate 320 grit edge, the utility gets an approximate 600 grit edge, and my Chef's knife gets a 1500-2000(?) - just a hint of scratch pattern remaining. This not only gives me best performance, but good longevity.

Here's a couple pics from a recent thread on edge aggression.
www.bladeforums.com/forums/showthread.php/1095175-Help-with-edge-aggression!#18

And if you ever have insomnia, here's some video where I go through a progression and describe my observations at each stage.
http://www.bladeforums.com/forums/s...Washboard-start-to-finish-vs-Cold-Steel-Recon
 
Really enjoyed the links and videos!
I used to grumble about serrated blades, since I have yet to have it proved that a serrated does anything better than a really sharp edge, but "Here in the Real World," as Alan Jackson would say, it's an extremely practical solution.
My Great Grandma's bread knife is about a .050 carbon steel and slices bread just fine without serrations, it's got a heck of a rrown from being whetted for over a hundred years.
So I'll take your advice to heart, I was a bit unsure whether just because I CAN take em up to 5u and finish em on a paper wheel, I should.
320-600 with no burr should be a better real-world compromise. It'll make it that much more fun when a customer brings in an occasional fine knife.
 
L2bravo said:
Are German knives soft? This is not what I would have expected. When I say German, Heinkel comes to mind. I have one, that hasn't "appeared" soft to me. What then, would you reccomend as a sharpening routine on it? Thanks for the info.
Click to expand...

I love the way Wusthof uses the "X50crmov15" to impress people who don't know steels- don't get me wrong, it's a good steel for the knives it's in, but they might as well just say, "kind of cheap and easy to mass produce stainless" on their blades. :)
 
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