How long should a razor edge last

Ankerson said:
Yeah, exactly.....

WTF is a hard steel?

Or a Soft steel.... ?

Like saying S30V is a hard steel...... WTF doesn't that mean to them.....

Because it makes no since at all.....
Click to expand...

Great, now we are on the same page!
It's mostly composition of the steel itself and the accuracy of it, however dpending on the steel the Heat Treat , Quench, and Tempering can give you better edge retention.
Especially with higher Carbon steels a good RC of 58-60 will give better retention due to the carbides formed with an good equal heat treat, a one secondquench, and the tempering to that RC afterwards.
This is MY understanding and MY opinion.

And what it means to the average masses is the harder the steel the better the edge retention which isn't technically false, but what is false is refering to higher quality steels as higher RC hardness.
 
Auraria said:
Great, now we are on the same page!
It's mostly composition of the steel itself and the accuracy of it, however dpending on the steel the Heat Treat , Quench, and Tempering can give you better edge retention.
Especially with higher Carbon steels a good RC of 58-60 will give better retention due to the carbides formed with an good equal heat treat, a one secondquench, and the tempering to that RC afterwards.
This is MY understanding and MY opinion.

And what it means to the average masses is the harder the steel the better the edge retention which isn't technically false, but what is false is refering to higher quality steels as higher RC hardness.
Click to expand...


I seriously doubt they even have a clue.......

Take an S30V blade that could be in the 55 - 61 range and compare that to a 1095 blade that could be in the 55 - 65 range.....

Or narrow it down and compare S30V at 58 to 1095 at 64.........

Or even farther comparing S30V at 58 to 1095 at 58....

And then saying S30V is a hard steel........ WTF are they talking about......

They aren't referencing RC hardness at all from they way I have been seeing the terms being used lately...

So the terms hard and soft have no meaning at all.....
 
Ankerson said:
I seriously doubt they even have a clue.......

Take an S30V blade that could be in the 55 - 61 range and compare that to a 1095 blade that could be in the 55 - 65 range.....

Or narrow it down and compare S30V at 58 to 1095 at 64.........

Or even farther comparing S30V at 58 to 1095 at 58....

And then saying S30V is a hard steel........ WTF are they talking about......

They aren't referencing RC hardness at all from they way I have been seeing the terms being used lately...

So the terms hard and soft have no meaning at all.....
Click to expand...

Unless they are referring to a specific RC or have specific blades they are comparing which are different in RC regardless of steel.
Otherwise nope, they are wrong haha.
 
Auraria said:
Unless they are referring to a specific RC or have specific blades they are comparing which are different in RC regardless of steel.
Otherwise nope, they are wrong haha.
Click to expand...

EXACTLY......

And we are back to the original question.... :D

WTF is a hard or soft steel.....?

And were in the hell are they getting that terminology from?
 
Ankerson said:
EXACTLY......

And we are back to the original question.... :D

WTF is a hard or soft steel.....?

And were in the hell are they getting that terminology from?
Click to expand...
Good question, probably just misunderstanding Steel composition with Rockwell Hardness I guess.
Or just misinformed.
I'm pretty sure the stickies take care of that though, if not go to the Knifemakers subforums and they have tons of books and links in their stickies for Steel.
 
Auraria said:
Good question, probably just misunderstanding Steel composition with Rockwell Hardness I guess.
Or just misinformed.
I'm pretty sure the stickies take care of that though, if not go to the Knifemakers subforums and they have tons of books and links in their stickies for Steel.
Click to expand...

Well they are getting it from someplace....... I can tell you that much....

And it's been lately too.......
 
Student762 said:
I have recently been trying to master the art of sharpening and I've been getting some awesome results, razor edges on all my knives, it's brilliant! But I have notice that the edges wear off quite quickly and need to be stropped often. I have a razor edge on a SAK camping model, Charge tti and a no name back lock. The tti keeps its edge for quite a while being s30v but the SAK and no name don't. The no name has a blade stamp claiming 440 stainless but it doesn't say much beyond that. I free hand sharpen so I was wondering whether I need to change the angle of my hone or work to a finer grit, I go to 600 now and use a leather strop. What should I do, or is it normal to have to strop this often?
Click to expand...

On the SAK (Victorinox/Wenger?), their steels are quite 'soft' (ahem) in the sense that they're not very abrasion-resistant at all (they'll even feel very 'soft' or even buttery on something like a diamond hone), and they're also not very 'hard' in terms of RC (Rockwell) hardness. If you are sharpening it to 15° inclusive (7.5° per side), the edge will roll or dent/ding in a heartbeat. The flipside is, because this steel is so 'soft' in that sense, it also takes very little work to make it sharp again. At such a thin edge angle, stropping is definitely your friend, and you will likely have to do it after every use. Trying to hone the edge back into shape on stones of most any kind will just scrub away much more steel than is practical. A knife like this should do reasonably well at perhaps 30° inclusive (15° per side), but it'll still need regular touching up, because the steel is that relatively vulnerable to edge damage by dents/rolling or abrasive wear. That's the 'soft' nature of it.

The S30V should be much more resistant to abrasive wear, thanks to the vanadium carbides in the steel. It may or may not still be 'soft', in the sense that the Rockwell hardness of the blade might be relatively low. Edges at relatively low RC can still roll or suffer other types of plastic deformation (dents or other impact damage), regardless of the abrasive wear-resistance of the steel. You're seeing that your S30V is holding up fairly well under your uses, so I'd assume this means it's sufficiently 'hard' (RC) to do the job.

The 'no name' lockback is obviously more of a mystery, though it's much more likely the steel is cheaply made and probably not very 'hard' on the Rockwell scale. That's likely due to both low-quality steel itself, and poor or incompetent heat treatment. Most 'cheap' knives of this variety won't hold fine edges very long, and many won't even take a fine edge in the first place. With these, you pretty much have to accept whatever you get.

On all these knives, 15° inclusive is likely much thinner than it should be. You'd likely be better off at 25-30° inclusive; most decent knives will perform well or excellently (depending on steel & heat treat quality) in this range, with maintenance performed at more reasonable intervals.


David
 
Last edited:
Ankerson said:
Well they are getting it from someplace....... I can tell you that much....

And it's been lately too.......
Click to expand...

I wonder if it's a youtuber or a forum as of recent.
Not pointing a finger or anything because I honestly have no clue.
OP I think you have a micro bur, you can strop.
If not check your angles and check it against the angle geometry on the edge itself.
You might be getting a micro bevel at let's say 15 degrees and after a few uses it goes back to the previous let's say 50 degree edge.
I would NOT sell the blade just because you are having problems with it.
 
Auraria said:
I wonder if it's a youtuber or a forum as of recent.
Not pointing a finger or anything because I honestly have no clue.
OP I think you have a micro bur, you can strop.
If not check your angles and check it against the angle geometry on the edge itself.
You might be getting a micro bevel at let's say 15 degrees and after a few uses it goes back to the previous let's say 50 degree edge.
I would NOT sell the blade just because you are having problems with it.
Click to expand...


There is a lot of misleading information out there, I know that.....

But this latest thing with the hard and soft steels is so far off it really got my attention......
 
Ankerson said:
There is a lot of misleading information out there, I know that.....

But this latest thing with the hard and soft steels is so far off it really got my attention......
Click to expand...

It's a head scratcher that's for sure.
However hopefully they learn the difference.
I didn't know for a few year while getting into blades the difference between steel types and RC Hardness.
 
Auraria said:
It's a head scratcher that's for sure.
However hopefully they learn the difference.
I didn't know for a few year while getting into blades the difference between steel types and RC Hardness.
Click to expand...

Well that's one of the reasons why I want to find out were it came from...... ;)

If you know what i mean.......
 
Auraria said:
I wish we had a stick called "Steel Types versus Steel Hardness".
That'd clear a lot of things up I think.
Click to expand...

There are a lot of factors that are involved in edge retention.

  1. Alloy content/Carbide percentage
  2. Edge geometry
  3. Blade Geometry
  4. Edge finish
  5. RC Hardness/Compression strength of the steel

Compression strength is directly related to RC hardness and since edge dull mostly due to blunting, rolling etc so the higher the RC is the longer the edge will go before it starts to deform so the edge will stay sharper longer compared to the the same steel at a lower RC hardness.

Wear resistance is important and is directly related to alloy content/Carbide content so that will have an effect mostly on more abrasive materials being cut.

Blade and Edge geometry are important because the thinner the blade is and the lower the edge angles are the easier it will move through the media being cut. Now if we get too thin for the use at hand the reverse will happen and the edge will dull too fast so a balance has to be met. Too high RC hardness and the edge will chip out too early and dull too fast.
 
Ankerson said:
There are a lot of factors that are involved in edge retention.

  1. Alloy content/Carbide percentage
  2. Edge geometry
  3. Blade Geometry
  4. Edge finish
  5. RC Hardness/Compression strength of the steel

Compression strength is directly related to RC hardness and since edge dull mostly due to blunting, rolling etc so the higher the RC is the longer the edge will go before it starts to deform so the edge will stay sharper longer compared to the the same steel at a lower RC hardness.

Wear resistance is important and is directly related to alloy content/Carbide content so that will have an effect mostly on more abrasive materials being cut.

Blade and Edge geometry are important because the thinner the blade is and the lower the edge angles are the easier it will move through the media being cut. Now if we get too thin for the use at hand the reverse will happen and the edge will dull too fast so a balance has to be met. Too high RC hardness and the edge will chip out too early and dull too fast.
Click to expand...

That is correct, I'm not just refering to edge retention though, I just mean in general the differences between the two so people won't make that mistake.
That's actually a really good quick list Ankerson
 
Auraria said:
That is correct, I'm not just refering to edge retention though, I just mean in general the differences between the two so people won't make that mistake.
That's actually a really good quick list Ankerson
Click to expand...

Figured I would make it simple and quick without getting too technical about it so people could understand it.
 
Ankerson said:
Figured I would make it simple and quick without getting too technical about it so people could understand it.
Click to expand...

I'll try talking to a mod later about a possible sticky or at least make a thread later.
At work and busy so really can't currently.
 
Auraria said:
I'll try talking to a mod later about a possible sticky or at least make a thread later.
At work and busy so really can't currently.
Click to expand...

I think Joe's thread is more than enough, he covers things really well.

I would have to add a lot more into it to make it a sticky...

HT and tempering, and all the technical information on how the alloys/carbides work and retained austenite and how that effects the steels performance.

Things can get very involved in a real hurry...
 
Ankerson said:
EXACTLY......

And we are back to the original question.... :D

WTF is a hard or soft steel.....?

And were in the hell are they getting that terminology from?
Click to expand...


If you'd like the opinion of a non geek in relation to steel hardness, here's my real world take on all this.

When I say a steel is soft, it means it is very easy to sharpen in a very short period of time and give me a serviceable edge, meaning it will cut stuff I want to cut, like say a cardboard carton. If I say a steel is hard, it means it's a son-of-a-gun to sharpen quickly and easily, but will probably not need to be sharpened as soon as a soft steel might. Case in point, some time ago I bought a replacement power hack saw blade to make a kitchen knife. The steel is so hard on the edge that it's awful. I called the manufacturer and spoke with their tech department to find out what the hardness rating of the cutting edge is, and they told me around 65-66, if memory serves. This blade is so tough to sharpen that it's always a chore, although it doesn't need it very often. If the steel were "softer" I'd just touch it up a bit with a sharpening steel for about 10-15 seconds, max, and get back to slicing tomatoes or steak or whatever.

If a knife cannot be relatively easily sharpened, as compared to say a KaBar USMC knife (57-58 RC, if memory serves) it will be fine so long as I have access to some of my power tools. Otherwise, it's staying in the drawer, and saved for the tough stuff in the kitchen.

With an EZ-Lap and most blades, a serviceable edge can be obtained quickly in the field.

So, in sum, softer is quicker to sharpen, with edges dulling more rapidly; harder is tougher to sharpen with edges generally lasting longer.
 
You must log in or register to reply here.
Back
Top