Various Knife Edges

cziv

cziv

Joined
Nov 24, 2005
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Is there such a thing as regular maintenance for a collection of about a dozen or so "users?" I'd swear I've been noticing some kind of phenomena. I don't know if it's normal i.e. the process of oxidation or something. :confused:

This doesn't happen with my safe queen (back-ups or I haven't really checked actually) but my knives that have been used and re-sharpened - and THEN not all of them but some of them.

I spend an hour or so touching up & stropping one of my users - last incident was my S30V Military. It was shaving sharp, cut in squiggles all the way down a sheet of copy paper sharp and with a sigh of contentment I pronounced it finished and set it down on the desk.

Fast forward about two weeks and I picked up the same Military and slit open a couple of business (thin - white paper) and noticed that it didn't glide effortlessly through either of them, slicing cleanly then tearing about 3/4 of the way through. :eek:

"WTF" says I, and I repeated my cutting wavy lines through copy paper and the edge had deteriorated to sharp but hanging up. I could get a single curve out of it but not change directions mid-cut w/o tearing the paper.

A couple of passes on the DMT xx-fine hone and about 6 passes on my strop and it was back to the way I sat it down 2 weeks previously. Anyone know what might be happening?
 
Im my experience the finer the grit finish and strop, and the less corrosive steel the less it seems to dull. I have noticed the same thing and you are not imagining it. If you think of it when a chef first picks up the knife for using he steels the blade to realign the edge. That's kind of what you need to do.

If you have a very polished edge and seal it from oxidation it slows this down a bunch. Factory edges do pretty well just sitting around because of the buff they receive.

I have never tested this by steel type but I'd guess that, like finish grit does change the variables a bit.

Joe
 
You might be killing your edge on the strop. That would be my guess. As far as magical edge degredation, that has been discussed before and nothing but anecdotal situations were presented though. You might also not be removing the entire burr. Hard to say.
 
I've noticed the same thing happen with a few knives. Drives me up the wall because half the time I think I'm imagining it. Sorry about your troubles but it does make me feel better knowing I'm not the only one who's encountered this.
 
i had a buck single blade folder back in the 80's that i kept shaving sharp with the ez sharp that i was using at the time. i could leave it in my pocket for a week and never use it and when i did need to use it the thing would be dull. i also carried an uncle henry 3 blade folder in a belt sheath that i sharpened on glass and sandpaper only. it seemed like it kept the edge a lot better than the buck which was finished off with a translucent arkansas super fine stone to a mirror finish. you would think that the polished edge would stay sharper since a polished edge resists corrosion a lot better.
 
At least I'm not the only one who's run into this. This last time I noticed this was with my S30V Military, pretty non-corrosive steel though. Low power magnification doesn't reveal any burrs or wire edges. Oddly enough my more corrosive RC-3 MIL is insanely sharp after months of sitting around and it's way more corrosive than S30V. Another one of those mysteries. Thanks. :)
 
Thanks fro the post, I thought I was nuts! Ive noticed this two. Id have a knife hair whittlin sharp and not use it for a while, then go to show someone how sharp it was and look like a dork when it didnt preform!
 
As we all knife steel will rust if left in the open air. I would imagine that the thinnest part of the edge might corrode after a time if left exposed. I also imagine that different finishes might cause this to happen more quickly/slowly. A mirror polish would possibly last longer than the finish left from a coarse stone for example.
Have you considered using mineral oil to protect your edges? It is food safe and tasteless as far as I can tell. I generally use a soft rag with baby oil on my knives. This keeps them free from rust and spotting. I will generally 'strop' the edge on my oil cloth as well as wiping the entire blade. I have not noticed any edge degeneration on my knives.
 
This is interesting. I've heard people talk about it before. In the back of my mind, I get the sense that this happens with S30V, but I might be wrong. I pulled out some of my old 52100 blades, which is the easiest edge for me to get super sharp, and they hold up. But I treat all carbon steels with Tuf Cloth after I sharpen them.

Hey Cziv, why don't you sharpen two of your S30V blades to super sharpness and treat just one with Tuf Cloth. Then let them sit for a few weeks and see if they're equally sharp. I'd love to hear how it works.
 
Twindog said:
This is interesting. I've heard people talk about it before. In the back of my mind, I get the sense that this happens with S30V, but I might be wrong. I pulled out some of my old 52100 blades, which is the easiest edge for me to get super sharp, and they hold up. But I treat all carbon steels with Tuf Cloth after I sharpen them.

Hey Cziv, why don't you sharpen two of your S30V blades to super sharpness and treat just one with Tuf Cloth. Then let them sit for a few weeks and see if they're equally sharp. I'd love to hear how it works.
Click to expand...

Okay, I'll try it. :)
 
cziv said:
Is there such a thing as regular maintenance for a collection of about a dozen or so "users?" I'd swear I've been noticing some kind of phenomena. I don't know if it's normal i.e. the process of oxidation or something.
Click to expand...

Can be a wire edge. Easy to mix with supersharp actual edge. Some steels are more plastic than others, and with those, wire edge is more significant issue. Deburring pads or running the edge through the edge of the wood block helps.
As for the edge degradation, there's this thing called metal relaxation effect, when metal tends to deform over time, one of the reasons steeling works better before each use.. With wire edge that probably is more pronounced too.
 
Gator97 said:
Can be a wire edge. Easy to mix with supersharp actual edge. Some steels are more plastic than others, and with those, wire edge is more significant issue. Deburring pads or running the edge through the edge of the wood block helps.
As for the edge degradation, there's this thing called metal relaxation effect, when metal tends to deform over time, one of the reasons steeling works better before each use.. With wire edge that probably is more pronounced too.
Click to expand...
I wonder if the metal relaxation effect is the same thing I heard about some stainless steels in the 1980's. I have a Puma Deerhunter from 1980 that takes a very sharp edge and loses it in storage without any use. A friend told me that some stainless blades are "self-healing," by which he meant that the sharp edge would over time round off and blunt itself in the absence of either corrosion or abrasion. Carbon steels don't do this, in my experience.
 
All these explanations sound great in theory. But the real cause of this issue is spite....Yes, spite..it's your knife's way of showing that it doesn't like being ignored for long periods of time...


Seriously....

:D
 
Bill1170 said:
I wonder if the metal relaxation effect is the same thing I heard about some stainless steels in the 1980's. I have a Puma Deerhunter from 1980 that takes a very sharp edge and loses it in storage without any use. A friend told me that some stainless blades are "self-healing," by which he meant that the sharp edge would over time round off and blunt itself in the absence of either corrosion or abrasion. Carbon steels don't do this, in my experience.
Click to expand...

This is my "limited" experience too.

ono724 said:
All these explanations sound great in theory. But the real cause of this issue is spite....Yes, spite..it's your knife's way of showing that it doesn't like being ignored for long periods of time...


Seriously....

:D
Click to expand...

I think you guys are onto something seriously. I'm experiencing this with S30V primarily. We know it wants to cut and then shift into working edge mode quickly. It must do it out of spite if you don't get it there. ;) I really think that oxidation which breaks down all things naturally is probably the culprit. The cure is use and attention!
 
So is the steel just oxidizing? It could be tested. Toss a freshly-sharpened knife in an airtight box along with an oxygen absorber (shake-n-bake hand warmer pouch).

And why would S30V be more susceptible than AUS-8 ? That seems backwards, given the % of chromium.
 
RandomAyes said:
So is the steel just oxidizing? It could be tested. Toss a freshly-sharpened knife in an airtight box along with an oxygen absorber (shake-n-bake hand warmer pouch).

And why would S30V be more susceptible than AUS-8 ? That seems backwards, given the % of chromium.
Click to expand...

I can't answer that RandomAyes. I use the old Uncle Ben's boil-in-bag packets in my tupperware tub of knives to combat moisture but oxidation may occur independently of moisture? I googled it got lost in the chemistry of it all.
 
I dont know, but i would like to see some serious testing on this because, my ZT0300 gets laserbeam sharp and after not touching it for a while it starts to drag while having...
Ive noticed this with other blades and steels as well, not just the s30V.
 
Nope, never had this problem from 320 grit to polished they could probably sit forever in a dry cool environment and not lose the edge.
 
Gator97 said:
Can be a wire edge. Easy to mix with supersharp actual edge. Some steels are more plastic than others, and with those, wire edge is more significant issue. Deburring pads or running the edge through the edge of the wood block helps.
As for the edge degradation, there's this thing called metal relaxation effect, when metal tends to deform over time, one of the reasons steeling works better before each use.. With wire edge that probably is more pronounced too.
Click to expand...

This.

It's either a micro burr or you used too much grinding force and the edge is relaxing. It happens, its science.
 
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