Sharpening K390

[6brx]

HI guy's new to the forum's, looking for first hand advice on sharpening K390. I have a wicked edge, was wanting to know angle and what finish..I usual cut a lot rope and some card board Thanks in advance

[TazKristi]

HI guy's new to the forum's, looking for first hand advice on sharpening K390. I have a wicked edge, was wanting to know angle and what finish..I usual cut a lot rope and some card board Thanks in advance

Hi, 6brx:
Welcome to our forum. I'm going to move this into our Off-Topic area (our byrd knife area is for discussions specific to our byrd knives).

We hope you enjoy your time with us.

Kristi

[MacLaren]

HI guy's new to the forum's, looking for first hand advice on sharpening K390. I have a wicked edge, was wanting to know angle and what finish..I usual cut a lot rope and some card board Thanks in advance

You could send Jim Ankerson a pm.
If anyone can tell ya, it would be Jim.

[The Meat man]

HI guy's new to the forum's, looking for first hand advice on sharpening K390. I have a wicked edge, was wanting to know angle and what finish..I usual cut a lot rope and some card board Thanks in advance

Hi 6brx! Welcome to the forum.

Generally speaking, the lower your angle the longer it will stay sharp. Of course, the catch is that lower angles also mean the edge is less stable and more prone to damage if you're not careful when cutting. It's a compromise between cutting performance and edge stability.

That said, K390 is really strong steel. I have a K390 Police 4 and the edge is currently around 9~10 degrees per side (18-20 inclusive.) The knife is one of my all-time favorite EDC knives and I've used it a lot on everything from cardboard and rope to plastic tubing, food prep, wood carving, and more without issue. The only time I damaged the edge in use was when cutting some thick plastic banding straps holding pallets of sheet steel and aluminum. Those straps are really thick and strong and I wasn't super careful when I cut them, and the edge rolled a bit. If I were you I'd shoot for maybe 14 or 15 degrees per side.

As for edge finish I've had good results from going up to around 600 grit then stropping with 14 micron diamond compound on basswood. I haven't played around with different grit finishes much.

Out of curiosity, what K390 knife do you have?

[6brx]

Thanks for the info and the advice so far. I have PM 2 and 3 in k390

[Cambertree]

I agree with Connor’s advice.

K390 will take a pretty thin, acute edge for a high carbide steel. I’d say it’s my favourite steel at the moment.

400 to 600 grit will give you a long lasting edge for rope and cardboard cutting.

I like to refine my edges a bit more with diamond and CBN strops. Just a couple of passes on each grit progression. I generally use 10,3 and 1 μm and sometimes go up to the submicron level.

Generally if you want to customise an edge for your particular needs and cutting style, just start off by grinding an acute edge, then if you get any damage, sharpen it out at a slightly more obtuse angle, or using a microbevel. When the edge stabilises you’ll know you have an edge thickness/angle which is optimised for your needs. After a while you’ll get pretty good at guessing what point to thin the edge out to to begin with.

[6brx]

HI guy's new to the forum's, looking for first hand advice on sharpening K390. I have a wicked edge, was wanting to know angle and what finish..I usual cut a lot rope and some card board Thanks in advance

Hi 6brx! Welcome to the forum.

Generally speaking, the lower your angle the longer it will stay sharp. Of course, the catch is that lower angles also mean the edge is less stable and more prone to damage if you're not careful when cutting. It's a compromise between cutting performance and edge stability.

That said, K390 is really strong steel. I have a K390 Police 4 and the edge is currently around 9~10 degrees per side (18-20 inclusive.) The knife is one of my all-time favorite EDC knives and I've used it a lot on everything from cardboard and rope to plastic tubing, food prep, wood carving, and more without issue. The only time I damaged the edge in use was when cutting some thick plastic banding straps holding pallets of sheet steel and aluminum. Those straps are really thick and strong and I wasn't super careful when I cut them, and the edge rolled a bit. If I were you I'd shoot for maybe 14 or 15 degrees per side.

As for edge finish I've had good results from going up to around 600 grit then stropping with 14 micron diamond compound on basswood. I haven't played around with different grit finishes much.

Out of curiosity, what K390 knife do you have?

Thanks for the information I have a paramilitary 2 and 3 in K390

[6brx]

HI guy's new to the forum's, looking for first hand advice on sharpening K390. I have a wicked edge, was wanting to know angle and what finish..I usual cut a lot rope and some card board Thanks in advance

Hi 6brx! Welcome to the forum.

Generally speaking, the lower your angle the longer it will stay sharp. Of course, the catch is that lower angles also mean the edge is less stable and more prone to damage if you're not careful when cutting. It's a compromise between cutting performance and edge stability.

That said, K390 is really strong steel. I have a K390 Police 4 and the edge is currently around 9~10 degrees per side (18-20 inclusive.) The knife is one of my all-time favorite EDC knives and I've used it a lot on everything from cardboard and rope to plastic tubing, food prep, wood carving, and more without issue. The only time I damaged the edge in use was when cutting some thick plastic banding straps holding pallets of sheet steel and aluminum. Those straps are really thick and strong and I wasn't super careful when I cut them, and the edge rolled a bit. If I were you I'd shoot for maybe 14 or 15 degrees per side.

As for edge finish I've had good results from going up to around 600 grit then stropping with 14 micron diamond compound on basswood. I haven't played around with different grit finishes much.

Out of curiosity, what K390 knife do you have?

Thank you for Welcoming me

[abbazaba]

I was a few years ago now, but my Police4 showed up pretty dull and I took it to 17dps on my WE. I think I went to 3000 grit and have only had to touch up on the Sharpmaker since. It would be pretty stable at a lower angle as well.

[JD Spydo]

Getting my first model in K390 is high on my list but I haven't yet gotten to test drive or sharpen one yet. I could give some advice based on many super performing steels I've sharpened over the years.

First off I now do just about all of my preliminary work with my Diamond benchstones. It truly saves a lot of time and you don't scream curse words nearly as much :D I've been using that approach ever since I got my first ZDP-189 model and that's been a few days ago.

Some of the better diamond sharpening tools are made by DMT, Norton, 3M, EZE-Lap and Atoma are all good from my experience. These supersteels are getting so hard and tough that in the next 5 years or so I may be going to diamond exclusively.

Spyderco's ceramic sharpening tools I like because I do like the finished edge I get with them. But two good friends of mine swear by SHAPTON stones for finishing work.

[Ankerson]

HI guy's new to the forum's, looking for first hand advice on sharpening K390. I have a wicked edge, was wanting to know angle and what finish..I usual cut a lot rope and some card board Thanks in advance

15 DPS and 400 or 600 grit depending on what you like would be fine.

400 grit would be best however especially for rope.

You could even drop it down to 280 grit if you wanted even more aggressive cutting.

However nothing beats a serrated blade on rope.

So if you are cutting a lot of rope I would look into getting one of the serrated models.

Like this as an example, will out cut any plain edge on rope period.

And get a Sharpmaker, all you would need.

[JD Spydo]

HI guy's new to the forum's, looking for first hand advice on sharpening K390. I have a wicked edge, was wanting to know angle and what finish..I usual cut a lot rope and some card board Thanks in advance

15 DPS and 400 or 600 grit depending on what you like would be fine.

400 grit would be best however especially for rope.

You could even drop it down to 280 grit if you wanted even more aggressive cutting.

However nothing beats a serrated blade on rope.

So if you are cutting a lot of rope I would look into getting one of the serrated models.

Like this as an example, will out cut any plain edge on rope period.

And get a Sharpmaker, all you would need.

And don't just stop at ROPE either Jim. I can't even begin to tell you all how many things I find that Spyderedges are advantageous at cutting. Any type of cordage cuts much better with a serrated edge and a Spyderedge to top that off.

Where I discovered the cutting power of a serrated Hawkbill ( or most other serrated blades for that matter) was by taking an SE Spyderhawk to work with me one day by mistake in a swamp/wetland area that I was working in at that time ( 2004) The cattails, reeds, vines and just about any type of woody plant you can think I discovered will sever almost instantly with a Spyderedge. About 5 times as fast as it would even with the best of plain edges.

And for the layperson ( someone who is not a sharpening fanatic like many of us here at Spyderville are) you just can't go wrong at all with the Spyderco 204 Sharpmaker. But you must and I mean absolutely MUST get all the extra stones available for the 204 Sharpmaker when you get one. By doing so the sharpening kit just has so much more versatility that it's like having about 12 sharpening tools in one.

Also JIM isn't Spyderco's Ultra-Fine stone about the Equivalent of 3000 grit in most applications? All I know is that every job I finish with a Spyderco Ultra-Fine stone comes out superbly sharp. And that Ultra-Fine stone is also great for straight razors as well.

[Ankerson]

HI guy's new to the forum's, looking for first hand advice on sharpening K390. I have a wicked edge, was wanting to know angle and what finish..I usual cut a lot rope and some card board Thanks in advance

15 DPS and 400 or 600 grit depending on what you like would be fine.

400 grit would be best however especially for rope.

You could even drop it down to 280 grit if you wanted even more aggressive cutting.

However nothing beats a serrated blade on rope.

So if you are cutting a lot of rope I would look into getting one of the serrated models.

Like this as an example, will out cut any plain edge on rope period.

And get a Sharpmaker, all you would need.

And don't just stop at ROPE either Jim. I can't even begin to tell you all how many things I find that Spyderedges are advantageous at cutting. Any type of cordage cuts much better with a serrated edge and a Spyderedge to top that off.

Where I discovered the cutting power of a serrated Hawkbill ( or most other serrated blades for that matter) was by taking an SE Spyderhawk to work with me one day by mistake in a swamp/wetland area that I was working in at that time ( 2004) The cattails, reeds, vines and just about any type of woody plant you can think I discovered will sever almost instantly with a Spyderedge. About 5 times as fast as it would even with the best of plain edges.

And for the layperson ( someone who is not a sharpening fanatic like many of us here at Spyderville are) you just can't go wrong at all with the Spyderco 204 Sharpmaker. But you must and I mean absolutely MUST get all the extra stones available for the 204 Sharpmaker when you get one. By doing so the sharpening kit just has so much more versatility that it's like having about 12 sharpening tools in one.

Also JIM isn't Spyderco's Ultra-Fine stone about the Equivalent of 3000 grit in most applications? All I know is that every job I finish with a Spyderco Ultra-Fine stone comes out superbly sharp. And that Ultra-Fine stone is also great for straight razors as well.

Spydercos UF is 3.0 Micron.

[marty_bill_]

All great advice. I learned to find the angle on any knife tho is take a sharpie and mark the edge. Use lightest stone and when you wipe edge clean leaving no sharpie marks that's the angle. Could be 17° on one side and 21° on the other side. And I'm not saying it's just Spydie knives it's all knives from any production maker. It's not a big deal, but with a WE you can fix that and make them the same on both sides. Just my .02 cents.