M390 Sharpening Issues

[CdnMitch]

Hi everyone, this is my first post...I have searched and searched for answers but no luck...and I really need the assistance of you guys and gals.

I have a pocket knife that has a blade comprised of M390, I can not get it sharp for the life of me (I have never run into this problem and have sharpened a lot of high carbon knives, M4 and some Japanese Gyutos that were powdered steel with high hardness).

I have tried whetstones (400, 1000 then 4000 grit) and I have tried the Spyderco Sharpmaker (diamond, coarse, fine then ultra fine).

The knife is an Olamic Wayfarer 247 and I do not know what hardness it is treated to.

I can not get a sharp edge no matter what method I try and no matter what angle I try to set the main bevel and subsequent micro-bevel. It seems the best luck I have had is holding the knife at an angle opposing the sharp maker rod and attacking it that way, but I can barely get the knife to cut paper.

Is M390 that difficult to sharpen? Does the heat treat and subsequent HRC have any impact on sharpening difficulty?

Any help is greatly appreciated!

 

[DeadboxHero]

Well, it could be a lemon but it's more likely that your just not holding a consistent angle and forming a burr, also not properly removing the burr without rounding or crushing your apex. You have to rule that out before coming to conclusions about steel and heat treatment. Your edge should be able to slice paper cleanly at 400 grit THEN you enhance the push cutting with higher grit. Convexity should be reduced at the bevel.

Remember, when you hear hoof beats, think horses not zerbras.

Rule out the obvious first before moving to more complex reasons.

Hi everyone, this is my first post...I have searched and searched for answers but no luck...and I really need the assistance of you guys and gals.

I have a pocket knife that has a blade comprised of M390, I can not get it sharp for the life of me (I have never run into this problem and have sharpened a lot of high carbon knives, M4 and some Japanese Gyutos that were powdered steel with high hardness).

I have tried whetstones (400, 1000 then 4000 grit) and I have tried the Spyderco Sharpmaker (diamond, coarse, fine then ultra fine).

The knife is an Olamic Wayfarer 247 and I do not know what hardness it is treated to.

I can not get a sharp edge no matter what method I try and no matter what angle I try to set the main bevel and subsequent micro-bevel. It seems the best luck I have had is holding the knife at an angle opposing the sharp maker rod and attacking it that way, but I can barely get the knife to cut paper.

Is M390 that difficult to sharpen? Does the heat treat and subsequent HRC have any impact on sharpening difficulty?

Any help is greatly appreciated!

 

[CdnMitch]

Well, it could be a lemon but it's more likely that your just not holding a consistent angle and forming a burr, also not properly removing the burr without rounding or crushing your apex. You have to rule that out before coming to conclusions about steel and heat treatment. Your edge should be able to slice paper cleanly at 400 grit THEN you enhance the push cutting with higher grit. Convexity should be reduced at the bevel.

Remember, when you hear hoof beats, think horses not zerbras.

Rule out the obvious first before moving to more complex reasons.

Thank you so much for the reply!

I am able to form a bur with about 20 passes on the 400 grit whetstone on one side, I then proceed to the other side and hit it about the same number of passes...will not cut anything!

I am seriously at a loss here, I have never had a blade that I could not get a sharp edge on. I have marked with sharpie, checked my angles. I just don't know what is up with this knife.

 

[Mo2]

Would recommend trying diamond stones, that 400 grit spyderco should cut after using it and removing the bur. Apex formation and Bur removal can sometimes cause issues. There may be a very small bur that's too hard to see.
Also the Vanadium in the steel is probably harder than the stones your using. Diamond or cbn is idea to make it easier.

 

[Obsessed with Edges]

It does sound like burr removal is probably where it's going wrong. Once the burr is seen from both sides, take great care to lighten pressure significantly while cleaning the burr up. Sounds to me like the edge is probably being blunted and/or rounded during burr removal, if it's going from burred to 'not cutting' that quickly.

Could also be that 'hitting it the same number of passes' from the other side might not be finishing the edge completely. Look to form a burr from one side (you've done this, by your description) and then form and verify the burr from the other side. Don't count passes; verify the burr is actually seen from both sides, before starting the burr cleanup process. And then go about that very gently and carefully. Check how it's cutting in paper, frequently, while you're doing that, so you can see where or if it's starting to turn bad again.

 

[DeadboxHero]

Thank you so much for the reply!

I am able to form a bur with about 20 passes on the 400 grit whetstone on one side, I then proceed to the other side and hit it about the same number of passes...will not cut anything!

I am seriously at a loss here, I have never had a blade that I could not get a sharp edge on. I have marked with sharpie, checked my angles. I just don't know what is up with this knife.

Stop counting passes. Useless.

Go back to the basics.

Sharpen one side, from shoulder to apex using sharpie to confirm it's all one angle; any facets or over convexity kill the edge.
STOP that side when you get a burr you can feel from the tip,belly, straight and heel nice and even.

Repeat on the opposite side.

STOP when you have a consistent burr on the opposite side of whats being sharpened.

DONE


Now

DEBURR

***LIGHT Touch, same angle, alternating passes on the same stone until burr is reduced and or removed**

No counting, big boy rules. Do it until you get the effect, not just blindly counting or following theatrics. Use the understanding of the process to get the effect.

At 400 grit you should be able to cut paper.

If not, your doing it wrong, go back.

BIGGEST factor for why peoples edges suck.

#1 lack of Angle control, do to lack of consistency and Dexterity.

Next, lack of burr formation

Also, lack of burr removal or crushing the apex by deburring to aggressively.

Easiest fix in the world. You just start over and put in reps.
Probably don't want to sharpen away a fancy knife though.

Good luck. Nothing we say beats just putting reps in. Get er done

 

[Eli Chaps]

All of what Obsessed with Edges and DeadboxHero said. Don't let your brain try to tell you what to do, let the blade tell you what it needs.

Get that burr on both sides regardless of number of passes. You'll get it. Maybe give it some time before coming back to it. When we get flustered we can struggle and that can create a nasty cycle.

 

[CdnMitch]

Would recommend trying diamond stones, that 400 grit spyderco should cut after using it and removing the bur. Apex formation and Bur removal can sometimes cause issues. There may be a very small bur that's too hard to see.
Also the Vanadium in the steel is probably harder than the stones your using. Diamond or cbn is idea to make it easier.

Thanks for the tips!

 

[CdnMitch]

It does sound like burr removal is probably where it's going wrong. Once the burr is seen from both sides, take great care to lighten pressure significantly while cleaning the burr up. Sounds to me like the edge is probably being blunted and/or rounded during burr removal, if it's going from burred to 'not cutting' that quickly.

Could also be that 'hitting it the same number of passes' from the other side might not be finishing the edge completely. Look to form a burr from one side (you've done this, by your description) and then form and verify the burr from the other side. Don't count passes; verify the burr is actually seen from both sides, before starting the burr cleanup process. And then go about that very gently and carefully. Check how it's cutting in paper, frequently, while you're doing that, so you can see where or if it's starting to turn bad again.

Thank you!

When you say see the burr from both sides...can you please elaborate? What I normally do is form a burr on one side, once its consistently along the entire edge I move on to the other side...is this what you mean?

 

[CdnMitch]

Stop counting passes. Useless.

Go back to the basics.

Sharpen one side, from shoulder to apex using sharpie to confirm it's all one angle; any facets or over convexity kill the edge.
STOP that side when you get a burr you can feel from the tip,belly, straight and heel nice and even.

Repeat on the opposite side.

STOP when you have a consistent burr on the opposite side of whats being sharpened.

DONE


Now

DEBURR

***LIGHT Touch, same angle, alternating passes on the same stone until burr is reduced and or removed**

No counting, big boy rules. Do it until you get the effect, not just blindly counting or following theatrics. Use the understanding of the process to get the effect.

At 400 grit you should be able to cut paper.

If not, your doing it wrong, go back.

BIGGEST factor for why peoples edges suck.

#1 lack of Angle control, do to lack of consistency and Dexterity.

Next, lack of burr formation

Also, lack of burr removal or crushing the apex by deburring to aggressively.

Easiest fix in the world. You just start over and put in reps.
Probably don't want to sharpen away a fancy knife though.

Good luck. Nothing we say beats just putting reps in. Get er done

Yes this makes perfect sense and what I have always done on my kitchen knives and other pocket knives. I have gone back and tried this and I can not get this knife sharp. I seriously am at a loss here, I can literally get any knife I have ever sharpened pretty sharp, measured with paper, popping hairs, shaving etc...that to me is acceptable sharp and I am good with that level. I think the blade has way too much beef behind the edge and to get this thing sharp you would need to go at around 30 degrees per side (not inclusive) otherwise you are just hitting the shoulders of where the edge starts from the blade. I think this knife is just poorly ground.

 

[CdnMitch]

All of what Obsessed with Edges and DeadboxHero said. Don't let your brain try to tell you what to do, let the blade tell you what it needs.

Get that burr on both sides regardless of number of passes. You'll get it. Maybe give it some time before coming back to it. When we get flustered we can struggle and that can create a nasty cycle.

Haha the nasty cycle and obsessive determination to get this knife sharpened is long gone now as I think it has to do with the blade being too beefy and needing to go at this at a crazy angle.

Using the sharpie trick if I hit the sharp maker at 20 degrees per side I am not even touching the edge, I am grinding the crap out of the blade where the edge starts. As I mentioned above I would need to be at around 30 degrees per side and this is something I have never encountered before. To get the edge sharpened imagine this.

I hold the knife vertical and up to the 20 degree per side sharp maker stone. If I am using the right side I would have to change the angle of the knife by turning it in towards me (away from sharp maker) another 10-15 degrees. This knife blade is really just problematic.

 

[DeadboxHero]

Show us a picture.

Use Imgur for image hosting, copy and past it here

Haha the nasty cycle and obsessive determination to get this knife sharpened is long gone now as I think it has to do with the blade being too beefy and needing to go at this at a crazy angle.

Using the sharpie trick if I hit the sharp maker at 20 degrees per side I am not even touching the edge, I am grinding the crap out of the blade where the edge starts. As I mentioned above I would need to be at around 30 degrees per side and this is something I have never encountered before. To get the edge sharpened imagine this.

I hold the knife vertical and up to the 20 degree per side sharp maker stone. If I am using the right side I would have to change the angle of the knife by turning it in towards me (away from sharp maker) another 10-15 degrees. This knife blade is really just problematic.

 

[brando555]

I think the blade has way too much beef behind the edge and to get this thing sharp you would need to go at around 30 degrees per side (not inclusive) otherwise you are just hitting the shoulders of where the edge starts from the blade. I think this knife is just poorly ground.

Yep, if it's really thick behind the edge a sharpmaker is going to take a long time.

 

[CdnMitch]

Show us a picture.

Use Imgur for image hosting, copy and past it here

I am going to try to get something up, but I have tried taking photos of the knife with my iPhone and its not really turning out so well!

 

[CdnMitch]

Yep, if it's really thick behind the edge a sharpmaker is going to take a long time.

So I have narrowed it down (I have tried diamond stones as well)

The grind is uneven on one side compared to the other...one side is steeper than the other. Taking off the amount of material I would need to is going to be a major chore and I would probably mess up the geometry of the lines of the blade so I think I am going to send back to Olamic and see what they can do!

 

[marchone]

If Olamic refuses to honor its warranty or even work on it due to your sharpening attempt send it to Josh@REK. He’ll clean it up.

I hope that helps.

 

[CdnMitch]

If Olamic refuses to honor its warranty or even work on it due to your sharpening attempt send it to Josh@REK. He’ll clean it up.

I hope that helps.

Thanks so much for the advice!

 

[Obsessed with Edges]

Thank you!

When you say see the burr from both sides...can you please elaborate? What I normally do is form a burr on one side, once its consistently along the entire edge I move on to the other side...is this what you mean?

Form the burr independently from both sides, before moving on to refinining steps. If the burr is only formed and verified from the first side, there's no guarantee the edge will be apexed from the opposite side, at least until the burr is then formed and verified on that side. The idea is to make sure both sides have clean, flat bevels intersecting at (hypothetically) an infinitely small point of intersection at the apex. You could make a nice, clean & flat bevel on the first side (verified by the burr's presence); but the opposite side might still not be flat, or it might have other incomplete bevels, or it might be rounded or blunted near the edge. That's why you want to go through the same process on the 2nd side as you did on the first side, i.e., sharpen until you verify a new burr along the full length of the edge.

Once you've formed and verified the burr on both sides independently, you can then move on to refining steps with secondary stones in the sequence, using those to refine & enhance the sharpness produced in the first stage, cleaning up the burr in the process.

 

[Dave Porter]

I am very new to this. I bought my first stones and sharpened my first knife in the middle of December. I bought a Para3 in M390 and I also could not get it sharp. I tried and tried and it wouldn't shave hair or anything. Like you, though, I was able to sharpen all of my kitchen knives to a very high degree.

Long story short, I kept working at it. Forming a full burr is the absolute key. Even at my higher grit stones I do not stop until I can feel the burr form from both sides. It will eventually happen. I also use a led headlamp when I sharpen to inspect the edge as I go. That helps tremendously as far as telling if your angles are consistent from both sides and if any parts of the edge are being neglected.

After I finish on my final stone, I move to a 4 micron poly diamond emulsion on leather. I spend a decent amount of time on this strop and it really seems to completely remove the burr from the last stone. I then move to 1 micron poly diamond on leather. Then I go to 1 micron poly diamond on basswood, and i use firmer pressure here. Then go to 0.25 poly diamond on basswood, and finish at 0.1 poly diamond on basswood. Resulting edge from this easily whittles free-standing hair.

Someone mentioned it above, and I agree that one of the biggest problems new sharpeners face is the inability to keep consistent angles on both sides of the blade/dexterity issues re: same. I struggled with this tremendously and believe it had a lot to do with why I was not able to get my knife sharp for a few weeks.

FYI- Like I said I am new to this and do not know enough to have an opinion on carbide tearout issues, etc. I can sharpen my M390 blade on King KDS water stones 300, 1000, 6000 as well as I can, and maybe even easier than I can on Venev diamond stones. I always finish on poly diamond strops, though.

 

[WC53]

With 390, I have better luck with diamonds on forward strokes. LIGHT PRESSURE, really light. I normally go 600-1200-5000 (or paste strop on wood). If I do too many passes with 390, it is almost like starting over. I wear and optivisor (I’m old) and go slow making sure I am pushing cutting lubricant in front of the edge. With 390 I have problems with trailing strokes for whatever reasons