Manix 2 edge keeps rolling

[zhyla]

I've had a 154CM Manix 2 (combo edge) since last August. It gets fairly light EDC use. Opening envelopes and packages, harvesting herbs in the herb garden... that's pretty much it. I've got beater knives if I need to do something stupid with a knife.

About a week after I purchased it I noticed the factory edge (straight portion) wasn't cutting very well at all. On inspection I found the edge (straight portion only) had rolled over enough to feel it with a fingernail. I'd never had this happen with a knife so I sharpened it and went about my business.

I've had this happen 3 times over the course of 10 months. On Saturday I sharpened it again because the edge was rolled over and this morning I noticed most of the edge is again rolled.

I'm confused and not sure what to do. Could it be I just got a poor heat treat?

There are bound to be questions as to my sharpening methods. I usually use sandpaper up to 2000 grit and some 3M honing paper. I recently got some 400/4000/8000 (Japanese grit) waterstones which I used this last time (and followed up with a strop). I also sharpened a relative's Ambitious which takes an amazing edge (hairs just fly off my arm) and while it did dull since I sharpened it 6 months ago it had no rolling that I could see. That's too much detail but the short answer is I am not as advanced in the art of sharpening as some others here but I'm not a total amateur either.

[xceptnl]

Based on the information I have learned from this forum, I would suggest that you are keeping that burr on the edge and it is rolling immediately upon use. Cliff would suggest you "destress" the edge by pulling it across the stone perpendicular to the edge. This should remove the old steel that has deformed and your sharpening will reveal new steel. I would say the burr is your main problem IMO>

[razorsharp]

+1 on destressing

[Pockets]

I agree about the burr. The burr will seem sharp when you use it on paper, hair, etc., but it rolls as soon as you cut anything solid with it.

[zhyla]

Ok will destress and report back. Thanks guys!

[Donut]

From what I've read about 154cm, it is a steel that likes to form a burr and is tricky to sharpen. I never noticed any issues with my 154cm Manix 2 on the sharpmaker.

Have you tried alternating strokes on the bench stones at the end of your sharpening? I know it's not super easy to do with bench stones, but it might help.

[Cliff Stamp]

In general, as noted in the above :

-cut the edge off before you sharpen
-remove the strop from how you sharpen
-take steps to minimize the burr during sharpen and remove it when you finish


However, all of this being said, having to sharpen a knife once every three months doesn't strike me as being poor performance. It depends on what you cut, but unless you restrict what you do to very new/clean materials it only takes one little piece of grit to catch and rake down along any edge to deform it.

Now if you rotate in other knives and they never do it, then after a few times you can likely conclude there is an issue with the knife which consistently rolls, but these types of conclusion are always prone to false results from time to time just due to random chance.

[zhyla]

However, all of this being said, having to sharpen a knife once every three months doesn't strike me as being poor performance.

Yeah, it was finding it rolled after a couple days of very light use that made me suspicious.

I removed a fair bit of material to get rid of that burr tonight. Then re-sharpened (omitting the strop -- maybe someone can explain why), and found a much fainter burr appeared. Then I spent a bit more time on the finest stone and finally got rid of the burr. I'm alternating sides as I sharpen, not really sure why this is happening yet but at least I'm aware of it now.

We'll see if it rolls again... I suspect it won't. Thanks everyone!

[guitarwolf]

I don't really understand how stropping would cause the burr to worsen? Isn't it convexing the edge, thus rounding it and removing the burr?

[A.P.F.]

I don't really understand how stropping would cause the burr to worsen? Isn't it convexing the edge, thus rounding it and removing the burr?

This link may help.

[guitarwolf]

thanks, this will keep me busy for a while!

[Cliff Stamp]

I don't really understand how stropping would cause the burr to worsen?

Stropping often :

-is done with a loaded surface contaminated with steel filings (and dirt)

This burnishes the edge rather than abrades it and like bending a spoon back and forth weakens it.

-is done with high force on a soft medium

This is mainly because you are trying to speed up the process or force angle matching. This again puts a lot of force on the edge and as well rounds the apex over.

Generally the best results with strops will be those that move the action to very similar to what happens on a stone (and then the optimal results are obvious from the stone of suitable grit).

I removed a fair bit of material to get rid of that burr tonight. Then re-sharpened (omitting the strop -- maybe someone can explain why), and found a much fainter burr appeared. Then I spent a bit more time on the finest stone and finally got rid of the burr.

That is the problem, if the edge is forming a burr that aggressively then it is very likely to have low strength and durability in use unless all damage was removed (that is all a burr is, visible signs of damage to the steel).

If it has the same behavior in early edge collapse it is either a problem with the steel or how it is being sharpened. The first thing to rule out is the second as that is easy to do and you really can't fix the first problem anyway if that is the case - it has to be a warranty/service claim.

[zhyla]

or how it is being sharpened

When I first sharpened it a year ago I was still intentionally inducing a burr (many strokes on one side, then flip it over), having learned that from woodworking people when I got set up to sharpen bench planes. It may be that I never fully got rid of that burr over the previous sharpening attempts. How it happened in the current attempt (alternating strokes) I am not too sure but it certainly was much less of a burr and didn't run the length of the blade. So I don't think I would blame the steel at this point.