Ripping out chunks when reprofiling on KME, what am I doing wrong?

B

blendergasket

Gold Member
Joined
Aug 15, 2005
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9
Hi!

I have a KME and I've sharpened a few knives successfully. I decided to go down to what I thought was 17 degrees per side, but realized after I got an edge cube that it's actually around 13-14 due to the big fat spyderco leaf blade.

I started with a Manix 2 LW in XHP and noticed after a while that there were big tears in the blade metal. I initially thought it was due to the steel, I have had issues with this knife chipping when I do stuff like cut carpet with it, but after what happened with my M4 manix I think it may be more to do with my technique.

I set it aside and tried to reprofile my M4 manix 2. This was slow going but going well until I noticed that there was a small rectangular chip in the blade on the part that I had achieved apex on. This knife is again at approx 13 - 14 per side (my angle cube came while I was in the middle of sharpening this knife, so the numbers on the XHP are just a guess).

I have been doing the reprofiling with "the beast" 50 grit stone. I have looked through the forum and read not to go all the way to apex with the 50 or 100 grit stones, which makes sense, but how do I know exactly when to stop and go to the next stone if I haven't hit apex? Is it just when all the sharpie is removed but there it not yet an apex?

Secondly, would this have to do with the amount of pressure I am applying or the angle I am sharpening at? Reprofiling, I am putting some pressure on the stone. Also, I am sweeping back and forth somewhat quickly. Is this a bad thing to do?

Would it be worth it for me to get the 100 grit stone to use after I have taken a fair amount of metal off with the 50 but well before apex?

Would the best way to get the chip out of my M4 manix be to just hit it with the 140 until I've taken enough metal off to get past the chip?

I'd love some perspectives on this. Thank you!
 
I would use the 140 and do what you suggested,also the factory angle that Spyderco sharpens the PM2 Manix and Military just to name a few is 15 degree's per side.
 
I also have to wonder if the edge is so thin on a Spyderco that the 50 grit is just to coarse and made to big of scratch's witch is what caused your problem,I try not to use anything to extreme when I reprofile a knife or sharpen it for the first time and only use a really coarse stone when I'm trying to repair a major chip in the blade,I find sometimes people think that the coarser the stone the better and sometimes less is more.

If you look at the metallic CBN stones for the my K02 they leave bigger scratch's in the blade and if you want a polished edge then they are no good because the scratch's are harder to get out on a blade made with S110v because it is so wear resistant,all I can say is take it slow until you get a better feel for the stones and steels your working with.

Also don't buy into the hype that diamonds are the greatest thing ever because they are not,diamond plates whether it be KME Gold Series DMT Atoma or any other brand are going to wear out and sometimes very fast for what you are paying for if you ask me,the problem is most people don't understand that the diamonds are just soldered in lace and wear tear off the plate when the diamond hooks into the steel,now the metallic bonded diamonds and CBN are different again because they all the way threw out the stone and have tin and copper surrounding them witch makes them anchored in place much better.If I were you start looking at some water stones as well like the Chosera's Shapton Glass or Silicon Carbide Gritalons from Russia I think he will cut them for the KME if asked to do so it's more when you start getting into S90v and S110v is when you need really good stones like diamonds because of the Vanadium content in S110v more so is higher and Vanadium from heating the blade makes it's between 80 and 82 Rockwell hardness witch is very hard.
 
Could be the pressure your using. Let the diamond do the work. Also dull the blade with issues so you can start anew. Then start with the 140grit. To get out chips you'll have to run it at a different angle, I generally like to do this on a bench stone before using the kme/edge pro.

The 50 and 100 grit are too coarse to apex as you already mentioned. But boy do they remove material fast.

I'd like to recommend the venev bonded diamond stones for the kme if you wear out your standard stones. Though not very coarse they do a great job giving more crisp edges and will last alot longer.
 
Thank you all for all the very insightful replies.

Mo2 said:
Also dull the blade with issues so you can start anew. Then start with the 140grit. To get out chips you'll have to run it at a different angle.
Click to expand...

Mo2, what is the significance of dulling the blade? Would that be more for a reference for me? Or does that aid in the sharpening? Also, thanks for the tip of adjusting the angle. It sounds like if I just raised it up to 15 I'd be killing 2 birds with 1 stone: making it a bit more stable, and making it easier to get out the chips. I love the idea of having a really acute angle on it though. Is adjusting the angle to get the chips out an absolute requirement? Or is it just to keep from removing so much steel?

wade7575 said:
I also have to wonder if the edge is so thin on a Spyderco that the 50 grit is just to coarse and made to big of scratch's witch is what caused your problem,I try not to use anything to extreme when I reprofile a knife or sharpen it for the first time and only use a really coarse stone when I'm trying to repair a major chip in the blade,I find sometimes people think that the coarser the stone the better and sometimes less is more.
Click to expand...

That's a good point. I will eventually have to resharpen my Urban. Duly noted about not using the 50 grit on such a thin blade.
 
My guess is it’s a mixture of to much pressure with to coarse of a grit with such a thin edge. You would be better off reprofiling with a say 2-400 and it taking longer then a 50 grit.
 
I would agree that it is likely too much pressure and grit. How new is the 50 grit? They are super aggressive when new before you run a handful of knives through them.
 
blendergasket the way I sharpen stuff is to use as little pressure as possible I know Ron from KME say's to just let the weight of the stone do the work but on some modern super steels that's going to work very well at all,I find just a tiny bit of pressure is all you need and the best way to judge that is with the steel that your sharpening is to start with no pressure and see how much metal comes off the knife and then increase pressure slowly until metal starts coming faster and there are steels like S110v where they are harder to sharpen even with good stones and you just have to put in them time and work to grind off the metal.
 
Thank you. I will refrain from apexing with the super course stones and trybtheb140 to see if that works better. I will also raise the angle by a hair to grind out the chips.
 
blendergasket said:
Mo2, what is the significance of dulling the blade? Would that be more for a reference for me? Or does that aid in the sharpening?
Click to expand...
If the edge is damaged, it's idea to remove the damage. That's what I learned from a few sharpeners... Not sure if its common practice here or not.

As for removing chips, this video can be helpful... Ive also just used a different angle to sharpen out chips before too. Lots of ways to do it I assume. Alot of guys here are far better than I am.




Here's cliff stamp on edge De stressing

 
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