Spyderco Forums

Fancier wrote:I'm glad I didn't have to make 820 cuts through rope on a mule without scales! Thanks for all your efforts!

I wore gloves. :D

Philo Beddoe wrote:I was being sarcastic Its been my thought all along that K390 if properly heat treated will make a awesome knife steel..

Hopefully at least as good as the almighty razor blade approved AEB-L :rolleyes: :D

It is a great knife steel.

endgame wrote:I hope youwore gloves!

Oh yeah...

This is from the Bohler website:

BOHLER K390 MICROCLEAN
Third Generation powder metal tool steel designed as an upgrade over A11. Vanadium reduced to 9% but Tungsten and Cobalt added. Edge retention comparable to A11, but greatly improved toughness. Harden and temper to 64-65 HRC. The best overall tool steel performance for knife blades.

BOHLER K294 MICROCLEAN(A11)
A 10% Vanadium, 2.45% Carbon Third Generation powder metal tool steel with extremely high edge retention. Harden and temper to 63-64 HRC. Difficult to grind and sharpen, but the choice for the best edge retention.

http://www.bucorp.com/knives.htm

bh49 wrote:Can you give an idea how long did it take to reprofile Native on 140 grit diamond plate and what angle did you reprofile it to?

Re-profiled to 15dps. I think I worked on it for maybe 1.5 hours, but I don't remember exactly.

Ankerson wrote:This is after 820 slicing cuts through 5/8" Manila rope.

Good Lord! I hope you're not sacrificing your right wrist by doing it all in one sitting (I assume you're not ambidextrous). Take care of your wrist man. We need more cutting results in the future!

P.S. YOu left a pretty clear latent print on that blade... sure hope you're not on the run.

Now I'm wondering if the K390 will outperform even the S110v in this manila rope cutting contest. It's a Bohler vs. CPM knock down, drag out, brawl. Can dialing back Vanadium a tad, and boosting tungsten, work together the make K390 more edge retentive than S110v, which instead of the K390's 1% Tunsten opted for 3.5% Columbian aka Niobium? Does this remind anyone of chemistry class?

If in fact K390 is, say 25% more edge retentive than S110v, does it then becomes a trade-off between the ultimate edge retention of K390 vs. the stainless quality of s110v? Can anyone comment on which steel well be more prone to breaking of a point under abuse than the other? Will s110v be easier then to keep sharp, and/or reprofile, than k390?

Well,

Using an edge pro / 140 atoma plate I had no trouble getting the K390 mule to cut off arm hairs much better than it did out of the box. I went on to the Edge Pro 220 and 320 stones but they could hardly abrade the K390. In fact they seemed like 5000+ grit stones. I hope to have a go with some mold-master stones tomorrow. I went with the standard 15DPS :D

This is such a cool steel!

Hey Jim,

This is probably a question I should know but how do you account for longer/shorter blades? Do you only cut with a specific section of the blade, etc?

It seems by logic if doing full draw cuts a longer blade would hold that edge longer than a short one. A low angle edge longer than a steeper one, etc.

Blerv wrote:Hey Jim,

This is probably a question I should know but how do you account for longer/shorter blades? Do you only cut with a specific section of the blade, etc?

It seems by logic if doing full draw cuts a longer blade would hold that edge longer than a short one. A low angle edge longer than a steeper one, etc.

IIRC from watching Jim's vids on the tube he uses only a small section of the blade for mostly push cuts or small draw cuts less than 1" He obviously will be able to shed more light on his procedures.

All I've got to say is that after using it, I'd buy any knife spyderco put out in K390. I touched up the edge on the sharpmaker and it was easily tree topping hairs in 10 mins.

Pretty awesome stuff!

Niles wrote:All I've got to say is that after using it, I'd buy any knife spyderco put out in K390. I touched up the edge on the sharpmaker and it was easily tree topping hairs in 10 mins.

Pretty awesome stuff!

Millie :D

I just got my Mules and Forum Native today.

I got the Native out of the box and immediately did some push cuts on some printer paper. It ripped and tore the paper and made ragged cuts. I tried it again on some tissue paper. Again, it caught and ripped the paper... I checked the edge with a loupe and checked the edge with my thumbnail... everything seemed OK. I scratched my head, then...

I decided to disassemble the cardboard shipping box from Spyderco. The slightly toothy carbide edge on the S110v really showed its stripes. Next, I cut a stack of used manila folders, binders, and office packaging into small strips. Zip, zip, zip.

After this activity, I took a look at the edge at 15x - and is showed absolutely no wear or deformation at all. Anyway, this are my initial impressions.

Cliff and Ankerson - thank you for your open dialogue. I really appreciate learning more about metallurgy and its application to our hobby. Thank you!

TedP

senorsquare wrote:Re-profiled to 15dps. I think I worked on it for maybe 1.5 hours, but I don't remember exactly.

Thank you for info. Hopefully I will not need to replace my stones after reprofiling.

Blerv wrote:Hey Jim,

This is probably a question I should know but how do you account for longer/shorter blades? Do you only cut with a specific section of the blade, etc?

It seems by logic if doing full draw cuts a longer blade would hold that edge longer than a short one. A low angle edge longer than a steeper one, etc.

Mostly use the belly, usually around 1/2 to 3/4 of the blade depending on what it is, or it would be a push cut....

DunninLA wrote:Good Lord! I hope you're not sacrificing your right wrist by doing it all in one sitting (I assume you're not ambidextrous). Take care of your wrist man. We need more cutting results in the future!

P.S. YOu left a pretty clear latent print on that blade... sure hope you're not on the run.

Now I'm wondering if the K390 will outperform even the S110v in this manila rope cutting contest. It's a Bohler vs. CPM knock down, drag out, brawl. Can dialing back Vanadium a tad, and boosting tungsten, work together the make K390 more edge retentive than S110v, which instead of the K390's 1% Tunsten opted for 3.5% Columbian aka Niobium? Does this remind anyone of chemistry class?

If in fact K390 is, say 25% more edge retentive than S110v, does it then becomes a trade-off between the ultimate edge retention of K390 vs. the stainless quality of s110v? Can anyone comment on which steel well be more prone to breaking of a point under abuse than the other? Will s110v be easier then to keep sharp, and/or reprofile, than k390?

Well from my own testing of K294 (A11) vs S110V, K294 was around 30% higher than S110V, not sure how that would work out in the production blades though and I haven't tested K390 in comparable knives to the customs I tested in K294 and S110V.

phillipsted wrote:I got the Native out of the box and immediately did some push cuts on some printer paper. It ripped and tore the paper and made ragged cuts. I tried it again on some tissue paper. Again, it caught and ripped the paper... I checked the edge with a loupe and checked the edge with my thumbnail... everything seemed OK. I scratched my head, then...

I decided to disassemble the cardboard shipping box from Spyderco. The slightly toothy carbide edge on the S110v really showed its stripes. Next, I cut a stack of used manila folders, binders, and office packaging into small strips. Zip, zip, zip

I don't know much about steel at all, but this was pretty much my experience with the S110V Native too. It wouldn't cut thin receipt paper without tearing, but zipped through two big cardboard boxes like a laser. I'm really enjoying this Native a lot so far! I'm looking forward to using K390 too if I can actually make usable scales!

Great work Jim!

I guess we don't need to have K390 at 5 dps for it to cut. :D

chuck_roxas45 wrote:Great work Jim!

I guess we don't need to have K390 at 5 dps for it to cut. :D

No it cut just fine, and it was still sharp enough to slice printer paper clean so it still had a usable edge on it.

Ankerson wrote:No it cut just fine, and it was still sharp enough to slice printer paper clean so it still had a usable edge on it.

After 820 cuts on rope, it still cut printer paper? Dayum! Must be almost as good as AEB-L. :p

chuck_roxas45 wrote:After 820 cuts on rope, it still cut printer paper? Dayum! Must be almost as good as AEB-L. :p

Yeah I guess. LOL :eek:

Jim, I'm worried about your wrist... :o

JNewell wrote:Jim, I'm worried about your wrist... :o

Took breaks after every 100 cuts....

I do that with all of Phil's knives and after I saw how hard that K390 was from reprofiling and sharpening it I figured it would take awhile.