AUS8 better edge retention than M4?! UPDATE: page 3

Definitely a lemon. CPM-M4, as made by Spyderco is absolutely awesome, and should hold it's edge 4 times longer than CS AUS8.
 
230grains said:
Yeah, I'm thinking that too. He did say he sharpened it up on an EP in a previous thread I believe. It very well could be a bad HT, but i've never had a dud from spyderco before.
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Maybe a bad HT? I did read he sharpened it on a EP, but that doesn't eliminate the possibility of a wire edge. 230grains, looking at your pix I'm sure you know enough to already know that... Jus say'in :D

Maybe the OP raised a burr on the EP, lined that burr up on end... Felt like it was not there anymore, when it really was. Cut the cardboard, the cardboard ate the weak burr/wire edge up in a few cuts, thus looking like a bad heat treat.

I would sharpen the Bradley again, finishing up with very very light pressure on the last grit. Then strop on a hard backed strop. I know when I used to use a EP, it was very easy to use too much pressure and raise too much of a burr. It's so easy to just grind away at the perfect angle and also push a little too much because it's hard to mess up. :)

Even freehanding, you want to use lots of very light strokes on the last stone. And I always like to strop, just to make sure there is no burr/wire edge :cool:

Then again, could very be a bad heat treat. I doubt it, but it's always a posibility.
 
So-Lo, I was actually agreeing about the wire edge theory, mentioning that he had sharpened it, the EP was inconsequential to my post really. I'm with ya on your idea though, but the HT is still a possibility, but doubtful. Either that or he laid the blade wrong on the EP table and gave it a MUCH shallower angle than he believed he did.
 
230grains said:
So-Lo, I was actually agreeing about the wire edge theory, mentioning that he had sharpened it, the EP was inconsequential to my post really. I'm with ya on your idea though, but the HT is still a possibility, but doubtful. Either that or he laid the blade wrong on the EP table and gave it a MUCH shallower angle than he believed he did.
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:D

Word hommie :p
 
This isn't a burr. You can easily see with your naked eyes the dents and deformations in the edge.

A wire edge would cause it do get dull fast. What I'm seeing is pretty much complete destruction of the edge.

I sharpened it by setting the flat of the ricasso on the table, so that should have kept the angle pretty consistent too. I can tell I have a pretty obtuse angle just by looking at how narrow the bevel is compared to the pics of the GB ankerson did at 30 inclusive.


So-Lo said:
Maybe a bad HT? I did read he sharpened it on a EP, but that doesn't eliminate the possibility of a wire edge. 230grains, looking at your pix I'm sure you know enough to already know that... Jus say'in :D

Maybe the OP raised a burr on the EP, lined that burr up on end... Felt like it was not there anymore, when it really was. Cut the cardboard, the cardboard ate the weak burr/wire edge up in a few cuts, thus looking like a bad heat treat.

I would sharpen the Bradley again, finishing up with very very light pressure on the last grit. Then strop on a hard backed strop. I know when I used to use a EP, it was very easy to use too much pressure and raise too much of a burr. It's so easy to just grind away at the perfect angle and also push a little too much because it's hard to mess up. :)

Even freehanding, you want to use lots of very light strokes on the last stone. And I always like to strop, just to make sure there is no burr/wire edge :cool:

Then again, could very be a bad heat treat. I doubt it, but it's always a posibility.
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Yes a wire edge will deform enough so you can see it with your eyes.

Resharpen it, using very very light stokes on the last stone, then skip the polishing tapes for now and strop on a hard backed strop, and try the test again. M4 is much better then aus8 :thumbup:

Could always be a bad heat treat, I know from some of your past threads your new at this. Believe me, and just try it, worst case you send it back in... They will not care if you sharpened it. :)
 
I immediately tried my GB on cardboard when I read this thread. After 40 cuts, it's still shaving sharp and as far as I can feel it still takes the same amount of force to cut the cardboard towards completing the 40 cuts. Since I have only a CE AUS-8A knife, I decided to use the coated S30V on my millie which I surmise is a little soft and as per Ankerson's tests, is comparable to AUS-8A. After 10 or so cuts the millie needed noticeably more force to cut than the initial 5 cuts.
 
I am fairly new to this but I know how to detect a wire edge. I can see them with my loupe, and also my pocket microscope. Most of the time I don't eve have to look, I can just feel them.

About 30 minutes ago I resharpened it on the edge pro, and I removed enough metal to get the big dings out. I had to form a pretty large burr to get into the fresh metal. It definitely had very deep deformations that couldn't possibly be a wire edge as they were almost as deep as the bevel itself.

Anyway, I broke down another box. This time I couldn't SEE any deformations, but I could definitely feel them with my fingernail when I ran it up the edge. Also when I steeled the edge with the ceramic I could hear all the little deformations when they caught on the rod. Most of them straightened back out. But I tried to see how sharp it was before steeling and again it would catch and tear paper, and would barely shave hair. Mind you, it was hair whittling when I was done with the edge pro.

I know you guys will tell me that I have a wire edge but I promise you that's not it. I've spent many hours sharpening in the last 4 months and Ive become familiar with burrs.
 
CrimsonTideShooter said:
I am fairly new to this but I know how to detect a wire edge. I can see them with my loupe, and also my pocket microscope. Most of the time I don't eve have to look, I can just feel them.

About 30 minutes ago I resharpened it on the edge pro, and I removed enough metal to get the big dings out. I had to form a pretty large burr to get into the fresh metal. It definitely had very deep deformations that couldn't possibly be a wire edge as they were almost as deep as the bevel itself.

Anyway, I broke down another box. This time I couldn't SEE any deformations, but I could definitely feel them with my fingernail when I ran it up the edge. Also when I steeled the edge with the ceramic I could hear all the little deformations when they caught on the rod. Most of them straightened back out. But I tried to see how sharp it was before steeling and again it would catch and tear paper, and would barely shave hair. Mind you, it was hair whittling when I was done with the edge pro.

I know you guys will tell me that I have a wire edge but I promise you that's not it. I've spent many hours sharpening in the last 4 months and Ive become familiar with burrs.
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10-4

On that note, it really may be the heat treat. I'd send it in, and call it to the attention of Sal, I'm sure he will want to see it himself :)
 
I know with the Sage series, Spyderco ht's and grinds the s30v blades in Golden, then ships em to Taiwan. Wonder if that's the same with the m4 GB's?
 
I think you have to try sharpening again and do the whole test again. I can hardly think cardboard would roll an edge, especially the edge of a quality steel. Has anyone of you had an edge roll on cardboard? Please look closely to see if it is a wire edge or bur that ba be rolling. Just my two cents.
 
Flatsman007 said:
I think you have to try sharpening again and do the whole test again. I can hardly think cardboard would roll an edge, especially the edge of a quality steel. Has anyone of you had an edge roll on cardboard? Please look closely to see if it is a wire edge or bur that ba be rolling. Just my two cents.
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Oh it can do a lot of damage to an edge in a real hurry depending on the cardboard.

M4 shouldn't roll though if it's a good HT.

If it had a wire edge and a good HT it would look like chips after one or 2 cuts then after awhile it would wear down back to smooth being very dull.
 
CrimsonTideShooter said:
I did some cutting tests today with my American lawman and gayle Bradley. The lawman is edge pro'd to 36 degrees inclusive, and the GB is EP'd at 42 inclusive.

Now here's the kicker - when cutting the exact same cardboard the exact same way the edge on the gayle Bradley rolls and deforms while the American lawman's edge doesn't change much at all. The edge on the gayle Bradley looked terrible and after ~30 cuts it was noticeably duller than the lawman.

What gives? I thought M4 was supposed to have great edge retention, so why did the lawman come out better?
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The most likely explanation is that you put a wire edge on the GB when you sharpened it.

CPM M4 will outcut AUS8 any day of the week and twice on Sundays.
 
I had the exact same problem with my S30V Native, bad HT for sure. I gave away to a friend, only paid 40 bucks and made good use of it, so I didn't care.
 
Before jumping to the conclusion of a bad HT some other testing should be done. Check Murray Carter's vid on how to fix a chip and he explains some testing methods.

A truly bad HT would be much different than a good HT with a low Rc. If you had a bad HT I would expect noticeable chipping in use and not just small chips but large half moon shaped nightmare's. Sharpening would also be difficult and it would seem like the edge is crumbling as the apex meet, like making a sand castle with dry sand.

A M4 blade with a low Rc would roll easily, show deformation similar to VG-10/AUS8, hold a burr in sharpening to the bitter end, and be strangly easy to grind, sharpen, and polish.
 
Knifenut, is that where he breaks off pieces of the blade in a pen (or a lighter) by flexing the edge into it? I seem to remember seeing that in a video.
 
Thats the strange thing, it is definitely NOT easy to sharpen on the edge pro. It noticeably takes longer than spydercos S30V, which would make me think that at the very least it got hardened?

I'm pretty confused with this thing. I'm not totally green when it comes to high end steels either. I've sharpened many zdp189 blades and 2 s90v blades, so I guess I have a tiny bit of experience sharpening these super steels.


knifenut1013 said:
Before jumping to the conclusion of a bad HT some other testing should be done. Check Murray Carter's vid on how to fix a chip and he explains some testing methods.

A truly bad HT would be much different than a good HT with a low Rc. If you had a bad HT I would expect noticeable chipping in use and not just small chips but large half moon shaped nightmare's. Sharpening would also be difficult and it would seem like the edge is crumbling as the apex meet, like making a sand castle with dry sand.

A M4 blade with a low Rc would roll easily, show deformation similar to VG-10/AUS8, hold a burr in sharpening to the bitter end, and be strangly easy to grind, sharpen, and polish.
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Yes but the blade he tests is ok so no breakage occurs. I think its more commonly known as a deflection test or brass rod test.

You put lateral pressure on the edge to see if it chips or takes a permanent deformation. If these things happen it usually means something is wrong with the steel.

A bad HT on a custom knife would be isolated, a bad HT in production would include a whole batch of knives.
 
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