Is k390 overrated?

[vivi]

Hans, your experience sounds a lot more similar to mine than OP's.

Me and Sal both took Police 4's to about 10 degrees per side without issue on common EDC tasks. I ran a 15dps microbevel, not sure about him.

My typical sharpening method for K390 was to establish a 10dps 300 grit bevel that was refined enough to at least scrape shave, then do one pass per side on the fine rods.

That gave it an aggressive slicing edge that could still push cut fairly well. Cleanly shaved but still had microserrations on the apex.

I haven't used my 15V yet, so K390 is still the #1 steel I have tried in terms of edge retention.

Every steel I've tried has seen a big increase in edge retention by both dropping the factory edge angle, and removing the factory edge. K390 was no different.

good luck OP. If you get frustrated and feel like giving up, I would be willing to put an edge on your K390 knife for you.

[JoviAl]

Looking at Larrin's data for high-speed steels, I noticed at least a few are rated "4" for corrosion resistance, including K390, M4 and 15V - I'm guessing in real world use there are probably differences between these three when it comes to resisting rust – has anyone had experience with 2 or all 3 of these regarding corrosion resistance?

I live in SW Ohio where the average humidity is 70%, although in the summer 80-90+% is not unusual, so I usually carry stainless steel knives (and a coated Sig Sauer pistol). I like DLC coated knives, but as some of you pointed out, the all-important edge is uncoated so it is still subject to rusting.

I’ve got knives in all three steels and live in the tropics (~35.C and 70-95% humidity year round). In my experience there’s a gulf between 15V and the other two, with 15V being surprisingly corrosion resistant and K390/M4 spot rusting in my pocket/storage. I use frog lube on everything except K390, M4 and basic tool steels, which get marine tuff glide every morning and evening if they’ve had an outing. I generally avoid buying K390/M4 these days as it is a real chore to look after here. If I move to a cooler/drier country they would be straight back on the cards as they’re really decent user steels.

[JoviAl]

I use whatever oil is convenient. And sometimes I'll be working on engines, digging holes in the dirt, or on a wilderness adventure, and I'll eat lunch without even washing my hands.

0A77ACA3-5DF6-4101-B0A4-13E66BDA5142 Large.jpeg

You sir are a wild man!

[ejames13]

Hans, your experience sounds a lot more similar to mine than OP's.

Me and Sal both took Police 4's to about 10 degrees per side without issue on common EDC tasks. I ran a 15dps microbevel, not sure about him.

My typical sharpening method for K390 was to establish a 10dps 300 grit bevel that was refined enough to at least scrape shave, then do one pass per side on the fine rods.

That gave it an aggressive slicing edge that could still push cut fairly well. Cleanly shaved but still had microserrations on the apex.

I haven't used my 15V yet, so K390 is still the #1 steel I have tried in terms of edge retention.

Every steel I've tried has seen a big increase in edge retention by both dropping the factory edge angle, and removing the factory edge. K390 was no different.

good luck OP. If you get frustrated and feel like giving up, I would be willing to put an edge on your K390 knife for you.

Going from scrape shaving to cleanly shaving with just one pass per side on fine rods seems like a big jump in sharpness.

[vivi]

Hans, your experience sounds a lot more similar to mine than OP's.

Me and Sal both took Police 4's to about 10 degrees per side without issue on common EDC tasks. I ran a 15dps microbevel, not sure about him.

My typical sharpening method for K390 was to establish a 10dps 300 grit bevel that was refined enough to at least scrape shave, then do one pass per side on the fine rods.

That gave it an aggressive slicing edge that could still push cut fairly well. Cleanly shaved but still had microserrations on the apex.

I haven't used my 15V yet, so K390 is still the #1 steel I have tried in terms of edge retention.

Every steel I've tried has seen a big increase in edge retention by both dropping the factory edge angle, and removing the factory edge. K390 was no different.

good luck OP. If you get frustrated and feel like giving up, I would be willing to put an edge on your K390 knife for you.

Going from scrape shaving to cleanly shaving with just one pass per side on fine rods seems like a big jump in sharpness.

when you sharpen at a more obtuse angle it doesn't take much grinding at all. this is why I keep telling people a microbevel can be applied with 1-3 strokes per side on the sharpmaker. more than that and you're running into compound bevel territory.

try it yourself. take a really coarse stone and establish a fresh edge on a knife. refine the apex as much as you can at the same angle on the same stone.

now run your fingernail along the edge and feel how toothy it is.

then do one stroke per side on the sharpmaker fine rods at 20 degrees. repeat the fingernail test.

then do one more stroke per side and another fingernail test.

even on very high wear resistant steels like K390 is only takes a few passes to polish off the teeth when using a more obtuse angle. so that's why I only do one or two passes per side, so that I don't polish off the microserrations in the process of polishing up the edge a bit.

[LazyOutdoorsman]

Hans, your experience sounds a lot more similar to mine than OP's.

Me and Sal both took Police 4's to about 10 degrees per side without issue on common EDC tasks. I ran a 15dps microbevel, not sure about him.

My typical sharpening method for K390 was to establish a 10dps 300 grit bevel that was refined enough to at least scrape shave, then do one pass per side on the fine rods.

That gave it an aggressive slicing edge that could still push cut fairly well. Cleanly shaved but still had microserrations on the apex.

I haven't used my 15V yet, so K390 is still the #1 steel I have tried in terms of edge retention.

Every steel I've tried has seen a big increase in edge retention by both dropping the factory edge angle, and removing the factory edge. K390 was no different.

good luck OP. If you get frustrated and feel like giving up, I would be willing to put an edge on your K390 knife for you.

Thank you for the offer to sharpen it, I appreciate it. However, I think I just have to practice to have any chance at getting good at my sharpening game.
Also, 10 dps is crazy, especially at 300 grit. I'm surprised you didn't get catastrophic chipping from looking at it lol.

[LazyOutdoorsman]

Just one question, is it fine to use ceramic to touch up or remove a small burr super high hardness/carbide steels like k390/15v? I've definitely heard that ceramic will not abrade the harder carbide types. https://scienceofsharp.com/2019/11/03/c ... n-maxamet/

[VandymanG]

Looking at Larrin's data for high-speed steels, I noticed at least a few are rated "4" for corrosion resistance, including K390, M4 and 15V - I'm guessing in real world use there are probably differences between these three when it comes to resisting rust – has anyone had experience with 2 or all 3 of these regarding corrosion resistance?

I live in SW Ohio where the average humidity is 70%, although in the summer 80-90+% is not unusual, so I usually carry stainless steel knives (and a coated Sig Sauer pistol). I like DLC coated knives, but as some of you pointed out, the all-important edge is uncoated so it is still subject to rusting.

I’ve got knives in all three steels and live in the tropics (~35.C and 70-95% humidity year round). In my experience there’s a gulf between 15V and the other two, with 15V being surprisingly corrosion resistant and K390/M4 spot rusting in my pocket/storage. I use frog lube on everything except K390, M4 and basic tool steels, which get marine tuff glide every morning and evening if they’ve had an outing. I generally avoid buying K390/M4 these days as it is a real chore to look after here. If I move to a cooler/drier country they would be straight back on the cards as they’re really decent user steels.

I’m curious have you tried Frog Lube Paste on the K390/M4? I don’t use it on my folders but I do use the paste on my fixed blades. I use the oil on all folders and the paste on all tool steel fixed blades. I’m not tropical islands or Florida humidity location wise so I haven’t tried the paste on the folders. Besides location the paste wouldn’t work on the pivot location so I guess that would still be an issue.

[vivi]

Hans, your experience sounds a lot more similar to mine than OP's.

Me and Sal both took Police 4's to about 10 degrees per side without issue on common EDC tasks. I ran a 15dps microbevel, not sure about him.

My typical sharpening method for K390 was to establish a 10dps 300 grit bevel that was refined enough to at least scrape shave, then do one pass per side on the fine rods.

That gave it an aggressive slicing edge that could still push cut fairly well. Cleanly shaved but still had microserrations on the apex.

I haven't used my 15V yet, so K390 is still the #1 steel I have tried in terms of edge retention.

Every steel I've tried has seen a big increase in edge retention by both dropping the factory edge angle, and removing the factory edge. K390 was no different.

good luck OP. If you get frustrated and feel like giving up, I would be willing to put an edge on your K390 knife for you.

Thank you for the offer to sharpen it, I appreciate it. However, I think I just have to practice to have any chance at getting good at my sharpening game.
Also, 10 dps is crazy, especially at 300 grit. I'm surprised you didn't get catastrophic chipping from looking at it lol.

I think people over estimate how thick knife edges need to be.

I run machetes thinner than a lot of people do pocket knives:

light chopping with ~10dps manix xl and temperance

https://streamff.link/v/8b5392cd

pacific salts with thin coarse edges being used for common utility work

Here's what I think is going on.

snip

good luck with your edge. nothing but respect for wanting to learn the right technique yourself.

[LazyOutdoorsman]

Hans, your experience sounds a lot more similar to mine than OP's.

Me and Sal both took Police 4's to about 10 degrees per side without issue on common EDC tasks. I ran a 15dps microbevel, not sure about him.

My typical sharpening method for K390 was to establish a 10dps 300 grit bevel that was refined enough to at least scrape shave, then do one pass per side on the fine rods.

That gave it an aggressive slicing edge that could still push cut fairly well. Cleanly shaved but still had microserrations on the apex.

I haven't used my 15V yet, so K390 is still the #1 steel I have tried in terms of edge retention.

Every steel I've tried has seen a big increase in edge retention by both dropping the factory edge angle, and removing the factory edge. K390 was no different.

good luck OP. If you get frustrated and feel like giving up, I would be willing to put an edge on your K390 knife for you.

Thank you for the offer to sharpen it, I appreciate it. However, I think I just have to practice to have any chance at getting good at my sharpening game.
Also, 10 dps is crazy, especially at 300 grit. I'm surprised you didn't get catastrophic chipping from looking at it lol.

I think people over estimate how thick knife edges need to be.

I run machetes thinner than a lot of people do pocket knives:

light chopping with ~10dps manix xl and temperance

https://streamff.link/v/8b5392cd

pacific salts with thin coarse edges being used for common utility work

Here's what I think is going on.

snip

good luck with your edge. nothing but respect for wanting to learn the right technique yourself.

Thanks for the manix vid. Although that was kind of painful to watch, I do feel a lot better about using my knives in a harder manner, especially with the cutting bevel closer to factory than 10-12dps

[VandymanG]

Hans, your experience sounds a lot more similar to mine than OP's.

Me and Sal both took Police 4's to about 10 degrees per side without issue on common EDC tasks. I ran a 15dps microbevel, not sure about him.

My typical sharpening method for K390 was to establish a 10dps 300 grit bevel that was refined enough to at least scrape shave, then do one pass per side on the fine rods.

That gave it an aggressive slicing edge that could still push cut fairly well. Cleanly shaved but still had microserrations on the apex.

I haven't used my 15V yet, so K390 is still the #1 steel I have tried in terms of edge retention.

Every steel I've tried has seen a big increase in edge retention by both dropping the factory edge angle, and removing the factory edge. K390 was no different.

good luck OP. If you get frustrated and feel like giving up, I would be willing to put an edge on your K390 knife for you.

Thank you for the offer to sharpen it, I appreciate it. However, I think I just have to practice to have any chance at getting good at my sharpening game.
Also, 10 dps is crazy, especially at 300 grit. I'm surprised you didn't get catastrophic chipping from looking at it lol.

I think people over estimate how thick knife edges need to be.

I run machetes thinner than a lot of people do pocket knives:

light chopping with ~10dps manix xl and temperance

https://streamff.link/v/8b5392cd

pacific salts with thin coarse edges being used for common utility work

Here's what I think is going on.

snip

good luck with your edge. nothing but respect for wanting to learn the right technique yourself.

Love the videos thanks for the link.

[JoviAl]

Looking at Larrin's data for high-speed steels, I noticed at least a few are rated "4" for corrosion resistance, including K390, M4 and 15V - I'm guessing in real world use there are probably differences between these three when it comes to resisting rust – has anyone had experience with 2 or all 3 of these regarding corrosion resistance?

I live in SW Ohio where the average humidity is 70%, although in the summer 80-90+% is not unusual, so I usually carry stainless steel knives (and a coated Sig Sauer pistol). I like DLC coated knives, but as some of you pointed out, the all-important edge is uncoated so it is still subject to rusting.

I’ve got knives in all three steels and live in the tropics (~35.C and 70-95% humidity year round). In my experience there’s a gulf between 15V and the other two, with 15V being surprisingly corrosion resistant and K390/M4 spot rusting in my pocket/storage. I use frog lube on everything except K390, M4 and basic tool steels, which get marine tuff glide every morning and evening if they’ve had an outing. I generally avoid buying K390/M4 these days as it is a real chore to look after here. If I move to a cooler/drier country they would be straight back on the cards as they’re really decent user steels.

I’m curious have you tried Frog Lube Paste on the K390/M4? I don’t use it on my folders but I do use the paste on my fixed blades. I use the oil on all folders and the paste on all tool steel fixed blades. I’m not tropical islands or Florida humidity location wise so I haven’t tried the paste on the folders. Besides location the paste wouldn’t work on the pivot location so I guess that would still be an issue.

Hi Greg,

Yeah, I started off using Frog Lube paste on everything (mainly because it’s food safe). I only switched to Marine Tuff Glide as the Frog Lube wasn’t lasting a full day of use at work. I really dislike the smell of Marine Tuff Glide and it’s apparently carcinogenic but it’s the only thing I’ve found that works for a full day outdoors with almost constant knife use on K390/M4/basic tool steels like 1095.

[Bill1170]

Looking at Larrin's data for high-speed steels, I noticed at least a few are rated "4" for corrosion resistance, including K390, M4 and 15V - I'm guessing in real world use there are probably differences between these three when it comes to resisting rust – has anyone had experience with 2 or all 3 of these regarding corrosion resistance?

I live in SW Ohio where the average humidity is 70%, although in the summer 80-90+% is not unusual, so I usually carry stainless steel knives (and a coated Sig Sauer pistol). I like DLC coated knives, but as some of you pointed out, the all-important edge is uncoated so it is still subject to rusting.

I’ve got knives in all three steels and live in the tropics (~35.C and 70-95% humidity year round). In my experience there’s a gulf between 15V and the other two, with 15V being surprisingly corrosion resistant and K390/M4 spot rusting in my pocket/storage. I use frog lube on everything except K390, M4 and basic tool steels, which get marine tuff glide every morning and evening if they’ve had an outing. I generally avoid buying K390/M4 these days as it is a real chore to look after here. If I move to a cooler/drier country they would be straight back on the cards as they’re really decent user steels.

I’m curious have you tried Frog Lube Paste on the K390/M4? I don’t use it on my folders but I do use the paste on my fixed blades. I use the oil on all folders and the paste on all tool steel fixed blades. I’m not tropical islands or Florida humidity location wise so I haven’t tried the paste on the folders. Besides location the paste wouldn’t work on the pivot location so I guess that would still be an issue.

Hi Greg,

Yeah, I started off using Frog Lube paste on everything (mainly because it’s food safe). I only switched to Marine Tuff Glide as the Frog Lube wasn’t lasting a full day of use at work. I really dislike the smell of Marine Tuff Glide and it’s apparently carcinogenic but it’s the only thing I’ve found that works for a full day outdoors with almost constant knife use on K390/M4/basic tool steels like 1095.

Hi Al,

I share your distaste for the odor of Marine Tuff-Glide, and I knew it wasn’t food safe. Where can I learn more about it being carcinogenic? If this can be verified I will stop using it.

[JoviAl]

I’ve got knives in all three steels and live in the tropics (~35.C and 70-95% humidity year round). In my experience there’s a gulf between 15V and the other two, with 15V being surprisingly corrosion resistant and K390/M4 spot rusting in my pocket/storage. I use frog lube on everything except K390, M4 and basic tool steels, which get marine tuff glide every morning and evening if they’ve had an outing. I generally avoid buying K390/M4 these days as it is a real chore to look after here. If I move to a cooler/drier country they would be straight back on the cards as they’re really decent user steels.

I’m curious have you tried Frog Lube Paste on the K390/M4? I don’t use it on my folders but I do use the paste on my fixed blades. I use the oil on all folders and the paste on all tool steel fixed blades. I’m not tropical islands or Florida humidity location wise so I haven’t tried the paste on the folders. Besides location the paste wouldn’t work on the pivot location so I guess that would still be an issue.

Hi Greg,

Yeah, I started off using Frog Lube paste on everything (mainly because it’s food safe). I only switched to Marine Tuff Glide as the Frog Lube wasn’t lasting a full day of use at work. I really dislike the smell of Marine Tuff Glide and it’s apparently carcinogenic but it’s the only thing I’ve found that works for a full day outdoors with almost constant knife use on K390/M4/basic tool steels like 1095.

Hi Al,

I share your distaste for the odor of Marine Tuff-Glide, and I knew it wasn’t food safe. Where can I learn more about it being carcinogenic? If this can be verified I will stop using it.

Hey buddy, hope you’re well.

When I ordered mine it came with a little paper leaflet stuck to it stating that it is locally recognised as a carcinogen and was not for human consumption. Maybe something specific to SG?

[JoviAl]

I’ve got knives in all three steels and live in the tropics (~35.C and 70-95% humidity year round). In my experience there’s a gulf between 15V and the other two, with 15V being surprisingly corrosion resistant and K390/M4 spot rusting in my pocket/storage. I use frog lube on everything except K390, M4 and basic tool steels, which get marine tuff glide every morning and evening if they’ve had an outing. I generally avoid buying K390/M4 these days as it is a real chore to look after here. If I move to a cooler/drier country they would be straight back on the cards as they’re really decent user steels.

I’m curious have you tried Frog Lube Paste on the K390/M4? I don’t use it on my folders but I do use the paste on my fixed blades. I use the oil on all folders and the paste on all tool steel fixed blades. I’m not tropical islands or Florida humidity location wise so I haven’t tried the paste on the folders. Besides location the paste wouldn’t work on the pivot location so I guess that would still be an issue.

Hi Greg,

Yeah, I started off using Frog Lube paste on everything (mainly because it’s food safe). I only switched to Marine Tuff Glide as the Frog Lube wasn’t lasting a full day of use at work. I really dislike the smell of Marine Tuff Glide and it’s apparently carcinogenic but it’s the only thing I’ve found that works for a full day outdoors with almost constant knife use on K390/M4/basic tool steels like 1095.

Hi Al,

I share your distaste for the odor of Marine Tuff-Glide, and I knew it wasn’t food safe. Where can I learn more about it being carcinogenic? If this can be verified I will stop using it.

I binned the leaflet that was stuck to it once I’d read it, but just did a quick check online and it seems like a bit of grey area -

I use it only on tools I’m certain I’m not going to be preparing food or doing any grafting cuts with, but the pungent smell puts me off buying any more.

[Bill1170]

I’m curious have you tried Frog Lube Paste on the K390/M4? I don’t use it on my folders but I do use the paste on my fixed blades. I use the oil on all folders and the paste on all tool steel fixed blades. I’m not tropical islands or Florida humidity location wise so I haven’t tried the paste on the folders. Besides location the paste wouldn’t work on the pivot location so I guess that would still be an issue.

Hi Greg,

Yeah, I started off using Frog Lube paste on everything (mainly because it’s food safe). I only switched to Marine Tuff Glide as the Frog Lube wasn’t lasting a full day of use at work. I really dislike the smell of Marine Tuff Glide and it’s apparently carcinogenic but it’s the only thing I’ve found that works for a full day outdoors with almost constant knife use on K390/M4/basic tool steels like 1095.

Hi Al,

I share your distaste for the odor of Marine Tuff-Glide, and I knew it wasn’t food safe. Where can I learn more about it being carcinogenic? If this can be verified I will stop using it.

I binned the leaflet that was stuck to it once I’d read it, but just did a quick check online and it seems like a bit of grey area -
IMG_5288.jpeg

I use it only on tools I’m certain I’m not going to be preparing food or doing any grafting cuts with, but the pungent smell puts me off buying any more.

Thanks, Al. There are some nasty ingredients in there. Our noses are intelligent enough to warn us about them. I haven’t oiled or otherwise treated my K390. Given my dry climate and retirement, only mild patination is evident on the Endura blade. I know from experience to wash and dry it soon after cutting any plant material.

Actually, come to think of it, I do oil the blade, because I use nose oil to remove tape residue. It’s very effective and always close at hand.

[RustyIron]

Before everyone gets all excited and starts running around in circles in their Tyvek suits, we might want to trade in our respirators for thinking caps.

While I'm no chemist, there are a couple questions that come to mind. Do these volatile compounds evaporate before you even get the knife into your pocket? Do these chemicals oxidize into stable compounds before you even wipe it onto the blade? As you might suspect, I wouldn't ask these questions if they didn't support my contention that this hysteria over "non-food-safe" lubricant is entirely unwarranted, and fomented by busybodies who have ulterior motives.

Before everyone starts hurling slings and arrows in my general direction, I ask that you READ just TWO SENTENCES beyond the highlighted text. Reading is still something taught in schools, right? It says, "...the product is not considered carcinogenic by NTP, IARC, or OSHA."

[JoviAl]

Before everyone gets all excited and starts running around in circles in their Tyvek suits, we might want to trade in our respirators for thinking caps.

While I'm no chemist, there are a couple questions that come to mind. Do these volatile compounds evaporate before you even get the knife into your pocket? Do these chemicals oxidize into stable compounds before you even wipe it onto the blade? As you might suspect, I wouldn't ask these questions if they didn't support my contention that this hysteria over "non-food-safe" lubricant is entirely unwarranted, and fomented by busybodies who have ulterior motives.

Before everyone starts hurling slings and arrows in my general direction, I ask that you READ just TWO SENTENCES beyond the highlighted text. Reading is still something taught in schools, right? It says, "...the product is not considered carcinogenic by NTP, IARC, or OSHA."

No offence taken To each their own. I use it because it works on K390, but the smell is no joke and given the amount of declared food safe products available that do a similar thing I don’t really see the advantage of using it over an alternative if it works as well.

[LazyOutdoorsman]

Before everyone gets all excited and starts running around in circles in their Tyvek suits, we might want to trade in our respirators for thinking caps.

While I'm no chemist, there are a couple questions that come to mind. Do these volatile compounds evaporate before you even get the knife into your pocket? Do these chemicals oxidize into stable compounds before you even wipe it onto the blade? As you might suspect, I wouldn't ask these questions if they didn't support my contention that this hysteria over "non-food-safe" lubricant is entirely unwarranted, and fomented by busybodies who have ulterior motives.

Before everyone starts hurling slings and arrows in my general direction, I ask that you READ just TWO SENTENCES beyond the highlighted text. Reading is still something taught in schools, right? It says, "...the product is not considered carcinogenic by NTP, IARC, or OSHA."

While not officially recognized by those groups, it is best to be on the safe side when something is suspected to be bad because you cannot undo the damage later on if it becomes confirmed that it directly causes harm.
Also, these groups may not list it as a carcinogen yet because to say that x material definitely does y requires proof, not just a correlation.

[VandymanG]

Did a 6 hour hike to Comet falls and the surrounding area. Carried the LeafJumper in my 5th pocket where it got soaked in sweat. Not sure why mine isn’t rusting like others are reporting. All I can figure out is that I wipe it down with Frog Lube oil before I leave home and use a lightly Frog Lube oiled rag, as soon as I’m done with whatever activity I’m doing, to wipe it down again. Thinking of cleaning it and forcing a patina since it’s not getting a patina fast enough for me.