Problem with my blade

M

m1ghtysauc3

Joined
Feb 10, 2011
Messages
211
I pulled out my large Insingo a couple days ago to cut up some cardboard for disposal. It performed well and the blade was no longer shaving sharp, which was to be expected. What was not expected, was the very rough edge left on the blade afterwards. It's very jagged where most of the cutting took place. I've tried sharpening it, with zero luck. Please note that all I have to work with is a Sharpmaker. It is what it is. What should I do? Send it to CRK? I know this shouldn't be work that the Sebenza can't handle. My Tenacious has been doing it fine for years.
 
Card board is rather nasty stuff to cut but it's not that nasty. I had a similar problem with a new Umnumzaan after trimming some ply wood, there were a lot of small chips out the edge. That knife has now been sharpened many times and seen much use but I have never had that issue again after shapening out the chips the first time. I think we are going to be going back to the old CRK and heat treat merry go round. :p
 
with a sharpmaker try this: 7 passes on the brown corners, 7 passes on the white flats, then strop it on the cardboard back of a notebook 7 times a side.
 
Not sure who's edge this was-CRK factory, previous owner or yours
Sounds like either the edge chipped or it still had a burr that snapped off. In either case CRK can sharpen it out for you or you can sharpen it out with your sharpmaker-but may take a little time depending on how bad it is. If it were a new knife I would send it back to CRK. If by any chance you rolled the edge rather than chipped it a steel(like what you might have with a kitchen knife set) works wonders.
Hard to tell the exact problem without photos
 
lathrop said:
with a sharpmaker try this: 7 passes on the brown corners, 7 passes on the white flats, then strop it on the cardboard back of a notebook 7 times a side.
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I tried this with no luck. I added more passes and still no luck. I guess it's gonna take a while.
 
Peter Hartwig said:
Not sure who's edge this was-CRK factory, previous owner or yours
Sounds like either the edge chipped or it still had a burr that snapped off. In either case CRK can sharpen it out for you or you can sharpen it out with your sharpmaker-but may take a little time depending on how bad it is. If it were a new knife I would send it back to CRK. If by any chance you rolled the edge rather than chipped it a steel(like what you might have with a kitchen knife set) works wonders.
Hard to tell the exact problem without photos
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I got it from a previous owner but it was listed as NIB. I doubt my cell phone could take photos well enough. I can tell you that I believe it's little chips. That's what it feels like and the light catches it pretty well.
 
I've encountered this same problem with my large 21...its going back to CRK as they JUST sharpened it not too long ago. It hasn't been used that much so I feel I shouldn't be having the issues I'm having. I'd like CRK to figure it out...
 
m1ghtysauc3 said:
I got it from a previous owner but it was listed as NIB. I doubt my cell phone could take photos well enough. I can tell you that I believe it's little chips. That's what it feels like and the light catches it pretty well.
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In that case if it were me, I would send it to CRK and let them re-sharpen or fix the problem. I am sure they will take care of you.Start by emailing them and letting them know of the problem, and take it from there. You are also right in the sebenza should not chip from cutting cardboard. Dull yes,but chip, no. At least that is my opinion.
Good luck
 
m1ghtysauc3 said:
I tried this with no luck. I added more passes and still no luck. I guess it's gonna take a while.
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Forget about the shapmaker and just get a good low grit stone, a few passes on that to remove the material needed to get the edge cleaned up and then go up through the grits untill you get the finish you want. Trying to remove that amount of steel with the sharpmaker is not too far off trying to hammer in a nail with a wet dish towel. :p
 
Haze said:
Forget about the shapmaker and just get a good low grit stone, a few passes on that to remove the material needed to get the edge cleaned up and then go up through the grits untill you get the finish you want. Trying to remove that amount of steel with the sharpmaker is not too far off trying to hammer in a nail with a wet dish towel. :p
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Where do you suggest I go for a stone?
 
m1ghtysauc3 said:
Where do you suggest I go for a stone?
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I personally use a large diamond stone. I have coarse stones from DMT and Smith's that I would buy again any day. I use them for rebeveling or situations like this where the edge is damaged and more material than usual needs to be removed.
 
Sounds like a burnt edge. This happens more often then many people tend to believe, no matter the company, if one sharpens on a machine the edge tends to heat up.

Removing steel through sharpening will resolve this as it removes the damaged steel exposing the correct heat treated steel.

DMT works well. A combo stone of course and fine and then onto the sharpmaker will work. I do most of my knives that way when at home.
 
My grinder can be set slow enough that I can sharpen half the knife away before it got too hot to hold never mind causing problems with the steel. I would hope CRK have a variable speed grinder or two at the shop. :p
 
Sharpmaker also makes some diamond rods that are suppose to be a lot better for reprofiling and removing matterial than the standard. I have never used them though.
 
marthinus said:
Sounds like a burnt edge. This happens more often then many people tend to believe, no matter the company, if one sharpens on a machine the edge tends to heat up.

Removing steel through sharpening will resolve this as it removes the damaged steel exposing the correct heat treated steel.

DMT works well. A combo stone of course and fine and then onto the sharpmaker will work. I do most of my knives that way when at home.
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I agree with this based upon my own experience with my own new Sebenzas. After a few routine maintenance sharpenings the problem disappears completely, at least in my experience. The DMT sharpening equipment are excellent products. Take a look at www.dmtonlinestore.com for the complete product line up. Don't worry. The blade on your new Sebenza will get better with use and a few more sharpenings. Don't let the cost of the DMT products keep you from investing in them. They last a long time, do a good job, and will serve you well. Just like your Sebenza. :thumbup:
 
I second DMT hones. My Sebbie 21 takes an edge past scary. Usually a few strokes on the ultra-fine (green) is enough to keep it hair-topping sharp. (I don't cut cardboard with it, tho'; an OLFA with replaceable blades works best when breaking down cardboard boxes.)
 
simplespeed said:
Mine came with a convex edge that was very very obtuse. Are you sure your hitting the whole bevel?
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That would be my question. If you are using a sharpmaker, it will take you a good while to hit the edge on a factory crk. I'd say get a coarse diamond and paint the edge with a sharpie. I'm guessing you'll find you are just hitting the shoulders of the edge.
 
marthinus said:
Sounds like a burnt edge. This happens more often then many people tend to believe, no matter the company, if one sharpens on a machine the edge tends to heat up.

Removing steel through sharpening will resolve this as it removes the damaged steel exposing the correct heat treated steel.

DMT works well. A combo stone of course and fine and then onto the sharpmaker will work. I do most of my knives that way when at home.
Click to expand...

I couldn't say if it was a "burnt edge" or not but I have had this issue with two CRKs. A few moments with a diamond stone to get past the nicks and then a sharpmaker and the problem is gone. I had always thought heat treat issues at the thinnest part of the blade but Marthinus may well have a point about the sharpening process. Disconcerting but not really an big issue to my way of thinking
 
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