An ideal edge for K390.

[jwthaparc]

I've got an endura 4 in k390 arriving tomorrow. My first spyderco! I'm pretty excited! I've been in the EDC game for just a little bit now, the sharpening game longer, and the kitchen knife game longer than that.

My side job, sharpening knives, brought me around pocket knives quite a bit, and eventually peeked my interest in them. So I've been dabbling with them more, and more. Eventually I couldn't help it, i had to buy a spyderco (specifically one with a high carbide steel) so I bought the k390 endura. I'm planning to get a PM2 in maxamet the first chance I get. Then I'll see where I want to go from their.

Anyway, that brings us to the point of the thread. I have quite a bit of experience sharpening, and more options for stones than anyone needs. I'm just wondering do you guys think I should stay around the dmt fine/venev 400 range (+stropping) or just say screw it, and polish it all the way up?

[Michael Janich]

Dear jwthaparc:

Welcome to the Spyderco Forum.

Stay safe,

Mike

[yablanowitz]

I'm no sharpening wizard and I have no idea what "ideal" is for you. That said, DMT extra fine at about 30° included produces a durable yet terifying edge on my K390 Police Models. Finer than that reduces the aggresiveness of the edge in my experience. YMMV.

Welcome aboard!

[aaronkb]

K390 takes a super nice polish which is fun, but I agree with others that it’s not ideal for performance.

Congrats on your first Spyderco and an awesome steel choice!

[VashHash]

I use either the dmt black or dmt blue on K390. I really enjoy how aggressive the edge is off the dmt black. Both of those stones are old though and it may be a slightly finer finish than advertised. Either way it seems to perform really well. I have a K390 mule that I polished up a good bit but I never got around to testing it out like that.

[Leksy]

Would share my experience. To begin with, I have a complete set of Venev diamonds, a set of different Dialux polishing compounds, and a guided sharpening system.

I received my K390 Dragonfly with coarse factory edge around 38-40 degrees (no microbevel), and immediately did a resharp to 34°.

At first, I can say that 7/5 diamond provides much higher "initial sharpness", comparing to White Dialux stropping. On 34° edge, the "initial sharpness" fades out pretty fast, but its "residual sharpness" holds very good. Actually, after a several months of use, it couldn't shave but still passed the "paper test".

Then, I decided to set up a new edge - about 25°. This time I have finished the sharpening session with OSB 3/2 and OSB 1/0 diamond bars. Actually the edge became almost mirror polished (though with some abrasion marks from the lower grits, because I was too lazy to get rid of them). This edge feels much more sharp and its "initial sharpness" lasts longer. I still have to use and test it further.

Now I've got my fresh Police 4 K390 - it has factory coarse edge (I think, around 30°) with some microbevel. I plan to use it until it shows a certain point of dullness. Then I will polish the bevel to a factory angle (30°) and set some fine 40° microbevel. I suppose, that setup will hold the edge insanely long (although, it will provide a little less satisfying cutting experience than at a lower angle). It will also easy to use the sharpmaker for touching that edge up.

Overall, K390 is my favourite steel right now (unless I am at humid or sweaty environment - that's where my Salts came out).

p.s.: I mean "degree value" as an inclusive angle. 7/5, 3/2, 1/0 micron corresponds to 3000 / 6500 / 9000 grit (approximately) for these Venev diamonds.

[dodgie02]

Would share my experience. To begin with, I have a complete set of Venev diamonds, a set of different Dialux polishing compounds, and a guided sharpening system.

I received my K390 Dragonfly with coarse factory edge around 38-40 degrees (no microbevel), and immediately did a resharp to 34°.

At first, I can say that 7/5 diamond provides much higher "initial sharpness", comparing to White Dialux stropping. On 34° edge, the "initial sharpness" fades out pretty fast, but its "residual sharpness" holds very good. Actually, after a several months of use, it couldn't shave but still passed the "paper test".

Then, I decided to set up a new edge - about 25°. This time I have finished the sharpening session with OSB 3/2 and OSB 1/0 diamond bars. Actually the edge became almost mirror polished (though with some abrasion marks from the lower grits, because I was too lazy to get rid of them). This edge feels much more sharp and its "initial sharpness" lasts longer. I still have to use and test it further.

Now I've got my fresh Police 4 K390 - it has factory coarse edge (I think, around 30°) with some microbevel. I plan to use it until it shows a certain point of dullness. Then I will polish the bevel to a factory angle (30°) and set some fine 40° microbevel. I suppose, that setup will hold the edge insanely long (although, it will provide a little less satisfying cutting experience than at a lower angle). It will also easy to use the sharpmaker for touching that edge up.

Overall, K390 is my favourite steel right now (unless I am at humid or sweaty environment - that's where my Salts came out).

p.s.: I mean "degree value" as an inclusive angle. 7/5, 3/2, 1/0 micron corresponds to 3000 / 6500 / 9000 grit (approximately) for these Venev diamonds.

I am and have been using a full set of edge pro diamond matrix stones, with great results. A lil touch up on my df2 recently with a 650 stone did wonders. Likely I got rid of the microbevel from touch ups on sharpmaker stones and resin bonded diamond stones tend not to form burrs so much. Took me al but 5 minutes to graze my thumb and out came the bandages haha. K 390 works wonders like this.

Question: have you gotten the venev stones with the tsprof? Can you compare them to edge pros?

[Manifestgtr]

I’ve done it both ways.

Im probably in the minority who slightly prefers K390 with a polished edge…at least for the moment. Who knows, that might eventually change. My current progression is really simple. A 300 and 1200 diamond plate, stropped down to .1 micron. I’ve found the first strop (8 micron in my case) to be realllyyy crucial. K390 has a tendency to hang onto its burr. That’s probably the biggest sharpening consideration I’ve run into with it.

Obviously, there’s no single “ideal” for every application/user…but I’ve been using this progression for the past few months and it’s been great. K390 still holds firm when given an ultra fine, polished edge.

[FK]

I have K390 Delica and Endura,,, my preferred edge is polished on hard leather strop with Gunny Juice for the Delica. On the Endura, again polished with Gunny Juice then a micro bevel with a few edge leading strokes on DMT Extra Fine,,, this give a nice aggressive apex with polished main bevel at 30 degrees and micro bevel (apex) at about 36 degrees for smooth cutting in any material.

Burr removal with K390 is with a hard felt strop with 1 micron CBN. I use a trailing stroke with the apex raised to about 45 degrees and dragging it almost parallel to the stroke direction,,, this cuts away the burr and leaves a nice clean apex. I find cutting away the burr is the most efficient method of removal,,, a trailing stroke on the strop will not remove the burr very efficiently and may make it worse. The burr removal is done prior to the micro bevel with DMT Extra Fine.

Regards,
FK

[FK]

Duplicate post

[FK]

Duplicate post

[ZrowsN1s]

K390's edge stability and retention are amazing. To really appreciate what it could do I went to 1200 grit diamond at 13DPS, then stropped at 1micron. It's a slicing machine, and it holds that sharpness better than most. (Police4 G-10)

[bearfacedkiller]

I think the choice of edge finishes has more to do with what you are cutting than what steel you are sharpening.

For most uses involving pocket knives I prefer a medium grit in the 800-1200 range.

[jwthaparc]

Would share my experience. To begin with, I have a complete set of Venev diamonds, a set of different Dialux polishing compounds, and a guided sharpening system.

I received my K390 Dragonfly with coarse factory edge around 38-40 degrees (no microbevel), and immediately did a resharp to 34°.

At first, I can say that 7/5 diamond provides much higher "initial sharpness", comparing to White Dialux stropping. On 34° edge, the "initial sharpness" fades out pretty fast, but its "residual sharpness" holds very good. Actually, after a several months of use, it couldn't shave but still passed the "paper test".

Then, I decided to set up a new edge - about 25°. This time I have finished the sharpening session with OSB 3/2 and OSB 1/0 diamond bars. Actually the edge became almost mirror polished (though with some abrasion marks from the lower grits, because I was too lazy to get rid of them). This edge feels much more sharp and its "initial sharpness" lasts longer. I still have to use and test it further.

Now I've got my fresh Police 4 K390 - it has factory coarse edge (I think, around 30°) with some microbevel. I plan to use it until it shows a certain point of dullness. Then I will polish the bevel to a factory angle (30°) and set some fine 40° microbevel. I suppose, that setup will hold the edge insanely long (although, it will provide a little less satisfying cutting experience than at a lower angle). It will also easy to use the sharpmaker for touching that edge up.

Overall, K390 is my favourite steel right now (unless I am at humid or sweaty environment - that's where my Salts came out).

p.s.: I mean "degree value" as an inclusive angle. 7/5, 3/2, 1/0 micron corresponds to 3000 / 6500 / 9000 grit (approximately) for these Venev diamonds.

I am and have been using a full set of edge pro diamond matrix stones, with great results. A lil touch up on my df2 recently with a 650 stone did wonders. Likely I got rid of the microbevel from touch ups on sharpmaker stones and resin bonded diamond stones tend not to form burrs so much. Took me al but 5 minutes to graze my thumb and out came the bandages haha. K 390 works wonders like this.

Question: have you gotten the venev stones with the tsprof? Can you compare them to edge pros?

I can imagine no matter what one of the spyderco k390s will do better with a lower edge angle. Mostly because it has the hardness to handle it. I think I've heard they can come in around 64-65 HRC. So I'm definitely going to be going with 30 inclusive at least.

I guess I'll have to test it out. I'll go with maybe the venev 400 (about 700 his grit), then try going up to the 2000 (8000-9000 his grit) stone.

The only times I've ever sharpened 10v class knives have been for customers. So in pretty excited that I finally get to see the performance, and how it responds to different grits first hand.

[Leksy]

Question: have you gotten the venev stones with the tsprof? Can you compare them to edge pros?

No, I use Zhuk ("Beetle") sharpener, it's simple and relatively cheap (3d printed by local manufacturer), but feels fine to me though. Have never used Edge pro, so can't compare, but they are pretty similar. My Venev diamod stones are double-sided, 150x25x10 mm size.
I also can say that OSB-bunched stones are much more satisfying at higher grits, they feel more stable in action, and are easier to clean.

[vivi]

I wouldn't even go up to a DMT fine.

The best experience I had with K390 was at 300 grit right off a coarse diamond stone.

Not only did I manage to get a cleanly shaving edge at that finish, but the K390 Police held on to shaving sharpness for over a month of carry.

I haven't seen any other steel come close to doing that.

K390 sharpened to a coarse edge could legitimately go half a year between sharpenings.

[jwthaparc]

I’ve done it both ways.

Im probably in the minority who slightly prefers K390 with a polished edge…at least for the moment. Who knows, that might eventually change. My current progression is really simple. A 300 and 1200 diamond plate, stropped down to .1 micron. I’ve found the first strop (8 micron in my case) to be realllyyy crucial. K390 has a tendency to hang onto its burr. That’s probably the biggest sharpening consideration I’ve run into with it.

Obviously, there’s no single “ideal” for every application/user…but I’ve been using this progression for the past few months and it’s been great. K390 still holds firm when given an ultra fine, polished edge.

I should add, for me an "ideal" edge would be one centered around edge retention. I'm not particularly concerned with it being extremely tough.

From your experience though, you've noticed k390 lasts longer polished? I'm definitely going to have to try going all the way up to .5 micron on my strops, and see where that takes me.

[vivi]

I’ve done it both ways.

Im probably in the minority who slightly prefers K390 with a polished edge…at least for the moment. Who knows, that might eventually change. My current progression is really simple. A 300 and 1200 diamond plate, stropped down to .1 micron. I’ve found the first strop (8 micron in my case) to be realllyyy crucial. K390 has a tendency to hang onto its burr. That’s probably the biggest sharpening consideration I’ve run into with it.

Obviously, there’s no single “ideal” for every application/user…but I’ve been using this progression for the past few months and it’s been great. K390 still holds firm when given an ultra fine, polished edge.

I should add, for me an "ideal" edge would be one centered around edge retention. I'm not particularly concerned with it being extremely tough.

From your experience though, you've noticed k390 lasts longer polished? I'm definitely going to have to try going all the way up to .5 micron on my strops, and see where that takes me.

Edge retention increases the lower grit you sharpen at. 440C sharpened to 200 grit will slice cardboard longer than S30V at 4,000 grit.

I'm not aware of any steels that increase in edge retention with higher polished edges.

[jwthaparc]

I’ve done it both ways.

Im probably in the minority who slightly prefers K390 with a polished edge…at least for the moment. Who knows, that might eventually change. My current progression is really simple. A 300 and 1200 diamond plate, stropped down to .1 micron. I’ve found the first strop (8 micron in my case) to be realllyyy crucial. K390 has a tendency to hang onto its burr. That’s probably the biggest sharpening consideration I’ve run into with it.

Obviously, there’s no single “ideal” for every application/user…but I’ve been using this progression for the past few months and it’s been great. K390 still holds firm when given an ultra fine, polished edge.

I should add, for me an "ideal" edge would be one centered around edge retention. I'm not particularly concerned with it being extremely tough.

From your experience though, you've noticed k390 lasts longer polished? I'm definitely going to have to try going all the way up to .5 micron on my strops, and see where that takes me.

Edge retention increases the lower grit you sharpen at. 440C sharpened to 200 grit will slice cardboard longer than S30V at 4,000 grit.

I'm not aware of any steels that increase in edge retention with higher polished edges.

I urge you to check this video out (assuming you can post links here) https://youtu.be/kkL4PAaKhqc

Its cedric and ada outdoors, fashion vs. function, mirror polished edge on s30v.

He has a few more videos that compare toothy vs polished edges on various steels. Along with his other edge testing.

My point is, that isn't true. There are quite a few steels that do better with a polished edge. There are a lot of other factors as well, but there are definitely steels like 1095, or s30v and most of the low allow steels that do much better with a polished edge.