Update!! M390, CTS-204p Chipping

[Cle808]

Just for clarification I want to add a few things that may help. The edges are not chipping during sharpening, they are showing up during use. All Chips are small but visible with the eye. The PM2 has been sharpened once and has developed a chip again. The domino has been sharpened twice as it had developed chips again after the initial re-sharpening. Each time sharpened I have done a full job through all my stones not touch ups. For sharpening I'm using diamond stones initially then moving to chosera pro for the ultra fine grits and then to 1/2 micron loaded strop and finishing with w bare roo strop.

God help me, I fear I'm about to open a can of worms here but here goes anyway.

Try your best edge without any stropping and see how it goes, especially if you can't be certain you're removing burrs and or if you're using the strop intentionally to remove burrs. Some people like to believe that strops are a magical burr eraser but all they do is bend the burr straight or break it off. If that's the case in your situation then that burr getting bent straight instead of cut off is where your chips are coming from. I don't know your technique but it's best to do everything possible on the stones to avoid or prevent excessive burrs.

Not saying I couldn't be wrong but I am making an effort to remove any burr prior to the strops. On my last two stones I'm finishing with very light, alternating, edge leading strokes. No burr was detectible from those stones through the strop with 1/2 micron cbn compound. On the PM2 I even checked with my 30x loupe after the fine stones and couldn't find a burr when I was done on the stones. Upon completion both edges appear burr free and will whittle a hair if I push it onto the edge.

[Cle808]

It seems like I am the fourth owner of a PM2 with M390 steel; when received, it had 4 areas where the original grind had been rolled/chipped (see below). I re-profiled it to 18 DPS and have not had any issues with chipping while cutting since then; I've been using it for about 2 months. :spyder:

That is about the size chips I'm getting.

[Chumango]

It is my opinion, not necessarily based on fact but by observation of a limited sample, that sharpening with powered high speed equipment can very easily leave a burr that can be very persistent. The edge does not have to be "burned" at all. It takes a few sharpenings to get past the weakened steel.

I have no idea how many blades come from the factory with a straightened burr, but I suspect many issues seen with new blades are due to this.

[kbuzbee]

Just for clarification I want to add a few things that may help. The edges are not chipping during sharpening, they are showing up during use.

Understood, but the scenario is likely quite similar to what I experienced.

Ken

[AwayFromMySpydieHole]

It seems like I am the fourth owner of a PM2 with M390 steel; when received, it had 4 areas where the original grind had been rolled/chipped (see below). I re-profiled it to 18 DPS and have not had any issues with chipping while cutting since then; I've been using it for about 2 months. :spyder:

My goodness, that is fairly significant. I have many spydies in m390, never had an edge anomaly that bad.

I think like others have said OP, your best/only option seems to be a sharpening and more use. Just make sure you grind away at least some of the apex. Maybe even "wipe" the apex off on a ceramic stone, then sharpen.

Hope you get it sorted. :)

[Cle808]

I'll report back in about a month after I rotate the two through daily carry. For now both edges are fresh and sharp. Thanks for all the info.

[jpm2]

I thought over heating while grinding the edge should anneal it, making it soft. I've done this myself.
What about too thin an edge during heat treat?

[kbuzbee]

I thought over heating while grinding the edge should anneal it, making it soft. I've done this myself.
What about too thin an edge during heat treat?

Annealling is a possibility but it generally takes holding the steel at the raised temperature for a longer period than it sees during belt sharpening.

Edge thickness... yeah, I suppose that's a possibility. But whatever the cause, it's been seen enough times, by enough people, in enough brands, and sharpening seems to frequently, eventually remedy the issue that it's a good first step.

Ken

[JD Spydo]

I don't know if this factor would make any difference to most of you all who use these two blade steels but it's part of my own sharpening regimen. I always finish my M390 Military model which I sharpen almost weekly. Actually you could say that I really tune it up and fine tune it weekly because I haven't reprofiled and thoroughly sharpened my M390 Military in almost a year. Because the M390 steel really holds an edge that good>> I can assure you I'm not kidding either.

But I do my finishing with my Spyderco 302 Ultra-Fine benchstone. I find that doing my final touch-up with a Spyderco ULTRA-FINE stone really keeps it performing razor sharp. EVIL D and others made mention of stropping but I only strop my M390 about twice a month or when I deem it necessary. It's one blade steel that just seems to love those Spyderco ULTRA-FINE STONEs. If you use them right it's almost like using a strop or some really high dollar ultra-fine stone.

[MacLaren]

My 204P Millie is just like it. Just a few strokes with both the Fine and Ultra Fine rods and she stays so sharp.

[vivi]

My best example was my 20CP Para 2, fresh out of the box cutting cardboard and it chipped so bad you could see it with your naked eye. I reprofiled it to 20 inclusive with a 30 micro bevel and it has no chipping issues unless I ding the edge on something.

40 degree back bevel with a 60 degree edge is much thicker than I run my choppers and two handed axes. I would hope a 3 inch bladed pocket knife doesn't chip under those angles

[AwayFromMySpydieHole]

My best example was my 20CP Para 2, fresh out of the box cutting cardboard and it chipped so bad you could see it with your naked eye. I reprofiled it to 20 inclusive with a 30 micro bevel and it has no chipping issues unless I ding the edge on something.

40 degree back bevel with a 60 degree edge is much thicker than I run my choppers and two handed axes. I would hope a 3 inch bladed pocket knife doesn't chip under those angles

I think he meant 10 degree per side, with a 15dps micro bevel.

Any time you see "inclusive" we're normally talking about the combined angle of both sides of the bevel. :)

[vivi]

Turns out I'm still learning to read :D Missed where he said inclusive.

[AwayFromMySpydieHole]

Turns out I'm still learning to read :D Missed where he said inclusive.

Happens to all of us. Lord knows I've done it at least a few hundred times. Haha

[Evil D]

My best example was my 20CP Para 2, fresh out of the box cutting cardboard and it chipped so bad you could see it with your naked eye. I reprofiled it to 20 inclusive with a 30 micro bevel and it has no chipping issues unless I ding the edge on something.

40 degree back bevel with a 60 degree edge is much thicker than I run my choppers and two handed axes. I would hope a 3 inch bladed pocket knife doesn't chip under those angles

Those numbers are inclusive sir.

[chuck_roxas45]

My M390 millie and my 20CP para have both had a rebevel or two and frequent touch ups. I had some visible chipping and I just thought my rough use was doing it. Turns out, they really didn't like ceramics since I could never sharpen away the tiny chips. I recently started using a fine diamond for touching up and I was quite surprised that after just one session, the tiny chips were almost gone.

[Cle808]

Update in original post. Thanks all