Soft CRK Sebenza

MreeceC

Gold Member
Joined
Jan 11, 2014
Messages
851
Alright... Let's start with I love CRK's. There blade material.. Not so sure. I have sharpened mine on a edge pro. Polished it up razor sharp.
The problem I am having is extreme edge role from very little use. The first time I was cutting para cord on a wood table. I took it back to the bench had to go down to a 400 grit stone. Got it back to crazy sharp and polished it back up. Today I had to cut a few zip ties.
This is what my edge looked like after.
In the pics you can see the light off the role.

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Just want to see what you guys think...
 
:eek: A table shouldn't role a knife edge. Zip ties have been known to damage edges.

I have never used 154 cm and cant say whether it's the steel or HT to blame.
 
Looks like it could be a profile issue. What angle are you sharpening the edge to? Judging from the size of the bevel it looks like it pretty narrow. Any narrow edge like that is going to have problems.
 
Looks like it could be a profile issue. What angle are you sharpening the edge to? Judging from the size of the bevel it looks like it pretty narrow. Any narrow edge like that is going to have problems.

22 degree. Maybe more at the tip because of the blade thickness increases at the end.
 
:eek: A table shouldn't role a knife edge. Zip ties have been known to damage edges.

I have never used 154 cm and cant say whether it's the steel or HT to blame.

I was pressing down pretty hard on the wood when I was cutting. I wouldn't think that would be a problem...
 
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Well that looks very unusual. My chisels never look like that even after chopping mortises or heavy paring. The chisels range from A2 to vintage. Like Rubicon Joey said maybe something with the angle. Certainly a call or email to CRK is in order.
 
This isn't one of the reproductions from ebay is it? They are typically using 440C and no telling what hardness. I have never had that happen on any of my knives, no matter what the steel. Definitely not on S30V or S35VN.

What steel is listed on the birth card?
 
With a heavy reprofile like you have done it is easy to end up with a wire edge that feels very sharp but rolls easily.
 
22 degree. Maybe more at the tip because of the blade thickness increases at the end.


That doesn't look like 22 per side, but it's hard to tell from pics at times though.
You're not talking about 22 inclusive are you ?
I doubt you are.

Zip ties can cause damage, and some woods can be tough on an edge if you're not going in at an angle.
Thats one of the reasons why the best cutting boards are end grain. The edge goes between the wood fibers instead of crushing against them.
 
:eek: A table shouldn't role a knife edge. Zip ties have been known to damage edges.

I have never used 154 cm and cant say whether it's the steel or HT to blame.

Do you mean 154CM on a Sebenza? CRK started with ATS-34, moved to BG-32, then to S30V and currently use S35VN. Unless I am off base I don't think 154CM was used.

As to the original question, the edge (especially if 22 degrees per side) side not be damaged by cutting para cord or zip ties. I sharpened mine last week to 17 degrees per side and so far have not had any issues. I read once that CRK sharpens knives to 18 - 19 degrees per side.
 
I highly doubt the edge to be 22 degrees inclusive. That is incredibly thin and doesn't appear so from the photo. I have my starbenza (s35vn) profiled at 30-35 degrees inclusive. I cut paracord all the time and on a hard surface with no chipping. I have cut zip ties before with no issue either.

I feel there is a possibility of 2 issues.

1) The edge was not finished properly and a wire edge remained resulting in the easy roll. As long as you are cutting off the burr cleanly in the finishing steps and maybe even stropping (I like to because I can never fully remove the burr off a stone) I don't see how else you would of achieved those rolls unless you were using the knife extremely hard--I would not classify what you did as hard.

2) You have knife with a possibly bad heat treat. If other possibilities already have been addressed then I would send the knife to CRK for them to test and possibly replace the blade. If the fault lies within CRK then you will be covered under warranty and receive a new blade at no cost.
 
If you notice the bevel widens at the tip. I actually matched the factory edge when I sharpened it. I think because of the hollow grind the bevel gets wider.
Either way whatever the angel should it be doing that? If I sharpened free has and just put a working edge on it how "finished" would that be? Just crazy to me it even does it.


Watch this. Gets good at about 8min

http://youtu.be/z1oq7PzjJkY
 
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If you notice the bevel widens at the tip. I actually matches the factory edge when I sharpened it. I think because of the hollow grind the bevel gets wider.
Either way whatever the angel should it be doing that? If I sharpened free has and just put a working edge on it how "finished" would that be?

I don't believe there is anything wrong with the edge angle you sharpened at. While a lot of people here are assuming a user end error fault, don't come to a conclusion yet. Try to weed out variables. There is nothing wrong with a 400 grit edge and from what I've read and experienced with, a lower grit edge performs just fine. How are you finishing the edge? You can test if you have a wire edge after your normal sharpening routine by running the edge of your knife across a hard piece of wood or plastic. That should force the skinny and weak metal to fold over to the side. When you are at the finishing steps of the sharpening process are you doing passes alternating sides? Being that you are using the edge pro, if you work one side for awhile, then flip the knife and finish the other you possibly will be left with a wire edge being that you are only working on one side for a "long" duration of time. I'd recommend alternating sides in the finishing steps to get a crisper edge and strop a bit to remove the last bits of a burr. Now if you have been sharpening properly and attaining a "clean" burr free edge you can go on to other possibilities.

Personally I see nothing wrong with cutting zip ties. Some have the opinion that cutting zip ties is too abusive and personally I think that's ridiculous. A knife should be used (unless its for a collection) and if you want to baby it, so be it but don't place labels on others for actions you deem abusive. My other question is was the zip tie the only thing the knife was cutting? Say if it was zip ties on aluminum tubing or some metal structure the edge of the knife pressing or hitting the hard surface can result in rolling. If it was a zip tie on some plastic packaging or wood there should be no issue, but something harder like aluminum or even some cheap pot metal rolling can and will happen. Now assuming that you were cutting only zip ties and if anything else, on a surface that wasn't too hard the rolled edge shouldn't be at user end fault.

After you've done these checks now you can assume that it is probable that your knife has a bad heat treat. In which case you should contact CRK (via email and/or phone) explain the issue with the knife, and settle it with them.
 
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I would sharpen again and make sure no wire edge is left. That may or may not have been the problem.
If that isn't it I would send it back to have the heat treat checked.
Good luck.
 
I don't believe that cutting zip ties constitutes abuse. HOW you cut your zip ties may constitute abuse.

I'd first check out the wire edge hypothesis.
 
Ok, sharpened it back up. No polish just took it back 1000 grit. I keep my passes on each side the same and stropped it out when I was done. It's super sharp. We will see how it does.

I was cutting zip ties off rubber cord that I was holding.

I emailed CRK with pics to see what they say. I will update you guys as I go along.

Thanks for all your input and great community!! You guys are very helpful and it nice to have someone to bounce things off of to make sure your thinking right.
 
Ok, sharpened it back up. No polish just took it back 1000 grit. I keep my passes on each side the same and stropped it out when I was done. It's super sharp. We will see how it does.

I was cutting zip ties off rubber cord that I was holding.

I emailed CRK with pics to see what they say. I will update you guys as I go along.

Thanks for all your input and great community!! You guys are very helpful and it nice to have someone to bounce things off of to make sure your thinking right.
By I keep on each side the same are you doing X amount of strokes on one side, flipping it and doing X amount of strokes on the other? If you are only working on a single side for a long duration of time the formation of a wire burr is very probably. If you did the test I mentioned earlier you can check if you do indeed have a wire edge after your sharpening process. In my opinion counting strokes doesn't do anything. All you should be doing is working one side till you have burr formation, work the other till you have burr formation. Then alternate sides to remove as much of the burr as possible and then strop a bit. CRK should have some good input hopefully and if it is indeed a heat treat issue CRK should sort you out.
 
By I keep on each side the same are you doing X amount of strokes on one side, flipping it and doing X amount of strokes on the other? If you are only working on a single side for a long duration of time the formation of a wire burr is very probably. If you did the test I mentioned earlier you can check if you do indeed have a wire edge after your sharpening process. In my opinion counting strokes doesn't do anything. All you should be doing is working one side till you have burr formation, work the other till you have burr formation. Then alternate sides to remove as much of the burr as possible and then strop a bit. CRK should have some good input hopefully and if it is indeed a heat treat issue CRK should sort you out.


Yes I work the burr. But when it gets into the 1000 and higher grit the burr gets are to feel. That's when I start to count.
 
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