Question about edge bur.

csalt09

Well-Known Member
I have been having issues with breaking off the edge bur. It doesn't want to bend the other way when stropping or through wood. It doesn't bend or break without a lot of pressure. This is with a .oo1" primary edge.
Is this good or bad?
 

John Wilson

Well-Known Member
I have found some steels are very difficult in this regard. AEB-L comes to mind. AEB-L is a really great steel, but it will raise a burr that will make you pull your hair out to remove. This stuff is very abrasion resistant and clings on for dear life rather than breaking off. If you aren't paying close attention you'll have a screaming sharp wire edge instead of an actual good edge. No amount of stropping seems to work if you have a wire edge. You have to go back to the belts and make sure you get rid of the burr with each belt progression.

If your burr won't break off it's probably too thick. Most likely it's a wire edge that flops from side to side. It feels sharp in one direction and dull in the other. Go back to your belts / stones and make sure you eliminate the burr on each grit progression. On your last grit, user ever decreasing pressure to get that last burr as thin as possible so it will strop off. I have found it also helps to finish the edge, edge-leading (cutting into the belt, direction wise). This tends to cut the burr off better than edge-trailing which kind of lets the burr ride the belt.

I have also found that cutting scrap leather will work on a burr. I take an old scrap of leather about half an inch wide and stand the leather up on edge and push cut it into fringe. I find it works better than dragging the edge across wood. Then I strop on leather with green chrome.
 

csalt09

Well-Known Member
Thanks John, great info. I never take the bur off when progressing through the belts. Ill definitely try it. I'm using W2 but the last two knives I did were Abe-l and I had that problem.
 

John Wilson

Well-Known Member
Man, AEB-L will drive you to drink with the edge burr. You'll begin to doubt that you ever knew how to sharpen a knife! Frustrating is an understatement. With AEB-L you really need to eliminate the burr at every new grit so that the only burr you ever end up with came from the last finest grit. If you don't, that burr will be thick and tough as nails and you'll never ever get rid of it. I never did that before, either- but after contemplating jumping off a bridge several times it's what I ended up doing and it works.

It seems like every time I rush on AEB-L I end up with a section of blade that cuts like a laser but snags paper badly. You can't even see the burr, you but you know it's there because of how it acts cutting paper. Once you get rid of it though- the knife is super ridiculous sharp.

CPM154 leaves a difficult burr, but AEB-L is even worse. The consolation is that once you do get rid of that burr, the edge is awesome and lasts a looong time. I have some kitchen knives in AEB-L that get used daily and have never been sharpened again after the initial sharpening when I made them. The scary edge goes away fairly quickly (a few weeks) but leaves a good working edge that seems to last well beyond any realistic expectation, even cutting onions, lemons and tomatoes constantly. All I do is rinse with water after every use and dry by wiping a towel down the blade.
 

Kurt Krueger

Well-Known Member
I've had great luck getting scary sharp edges on AEB-L. I use an Edge Pro, so no machine grinding. My process moves up from 120, 220, 400, 600 and to 1000 (5000 Chosera / 8000 Shapton) and then a leather strop. What I do is establish the edge with the 120 stone until I've got an even bevel on both sides and have turned a burr down the full length of the blade. Once I've done that, I flip the blade over and make one pass with the stone to remove the burr, moving toward the edge, not away from it, and then start with the next finest grit, following the same process. If I want to go crazy, or if doing hair shears, I start with the 1000 grit stone and go up through 5000 grit polishing tape.

Hope this helps.

-Kurt
 

me2

Well-Known Member
How are you all sharpening AEB-L that there is such a tenacious burr? Similar steels I've worked with sharpening wise were super easy to deburr and sharpen.
 

John Wilson

Well-Known Member
I'm using my 2x72 on the slack for a convex edge. 600 then micron belt, followed by leather strop with green chrome.

AEB-L has given me fits that no other steel has ever given me. It's not a big deal once you get a process, but in my experience with it (about 50 knives) it is a slightly different animal. Mine are hardened to 61-62.

Before I began making knives, the only other knives I'd had a similar issue with are Tojiro kitchen knives. I used to do those on stones and they behaved very similarly. To my knowledge, the Tojiros are VG-10.
 

me2

Well-Known Member
Are the belts cooled? The only time I power sharpened them was on a water cooled wheel. A rather large burr was there but was easily removed.
 

John Wilson

Well-Known Member
I spritz with water to keep the belts wet when sharpening. I am also running the grinder at slow speed (~20%)
 

John Wilson

Well-Known Member
I'm really hoping someone who has used a lot of AEB-L will chime in. I'd love to find out how to make the process easier.

I can tell you this, too- AEB-L grinds differently. It is very "hairy" when you grind it and the grinds clump together like steel wool and will smolder when sparks land on the buildup. It's like dryer lint. Sometimes when grinding I will throw handfuls of water from the quench bucket into my dust collector inlet funnel to quench the little embers that form. I also run a water trap before my dust collector blower. You do not want this stuff in your dust collection system with sawdust. It smolders a long time. After grinding, I pull the buildup clump off of my dust collector funnel walls and it's just like cleaning the dryer filter screen.
 

Matt de Clercq

Well-Known Member
I'm really hoping someone who has used a lot of AEB-L will chime in. I'd love to find out how to make the process easier.

I sharpen AEB-L the same way that I do any other steel. I use the long side of my rotary platen at 25% speed. 120, 400, 600, 800 and an old 1200 grit belts. After establishing a burr with the 120, I remove those scratches alternating sides. It usually takes about 8 passes per side. I continue this method all the way through the grits. The burr is not removed,it just gets smaller and thinner after each grit. The worn out 1200 grit belt (I think it's a Norax) gets more passes and I lighten up the pressure as I see the burr turn to really thin foil like material and start falling off. When the foil is gone I lightly strop it forty times alternating sides and then I'm done. It usually takes 5 to 10 minutes. The rotary platen, slow speeds and sharp 120-800 grit belts are key. I hope this helps
 

John Wilson

Well-Known Member
You can use a worn out 400 grit belt with some green chrome on it in place of a higher grit belt for now. I find AEB-L gets almost as sharp as it's going to be at 600 grit and some leather stropping. Beyond that it's polishing for smoother cuts. But it will get incredibly sharp at 600 after stropping, if the edge is thin enough. (I'm talking about using a belt grinder here.)

What kind of knife is it? For a working knife, a slightly toothy edge (600 grit) can be very desirable and even preferable if you are cutting tough media like rope, straps, or even tomatoes. A toothy edge is sometimes required for the task at hand. The perfect edge for fish is the worst edge for tomatoes.

You can do just about anything you want with 1000 grit and 6000 grit water stones followed by a strop.
 
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John Wilson

Well-Known Member
Also, if your edge just isn't getting sharp- I'm willing to bet that edge is thicker than you thought it was.

I've started taking my AEB-L blades to .005 - .007 before sharpening. After hand sanding they'll cut you. Now when I sharpen I don't have the horrendous problems I was talking about earlier in this thread. When I started using AEB-L I was leaving the edge in the .015 range then trying to convex it. No bueno.
 

csalt09

Well-Known Member
I don't have a problem with getting it sharp just wondering if there was a issue with my heat treat. I sometimes have issues with getting the bur off but not always. I will make a mental note to see if it is due to the edge thickness. I may be leaving it to thick like your saying.
 
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