Explaining Edge Retention To A New Knife Guy

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Furious_Toast

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Jul 28, 2014
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Alright, so today I was having a conversation with a buddy of mine about blade steels and edge retention when he asked a question i couldn't answer. How much longer will certain steels hold an edge than your basic 420/440 $20 or cheaper walmart knife. So thats it, how much longer will 8cr13mov, 154cm, s30v, and s90v hold its edge than a very common cheap steel?

I know the retention is exponential but I couldn't give numbers or put it into perspective, and I didnt just want to make anything up.

Thanks and happy new year!
 
Some steels hold it a LOT longer. I'm sure some people will be along soon with multitudes of excrapola and numbers for you.

I have a couple of older 420 and 440x knives I still carry because I like them. When they need it I strop or stone them. Pretty simple. Unless one does a lot of cutting all day, I don't find the frequency of sharpening such blades to be bothersome at all.

I pay attention to edge retention more with serious bush knives where I might be away from homefield for a while. Anything other than that, I have no problem with sharpening when necessary. if I like the knife, and it takes an edge satisfactory to me, it doesn't matter what the steel is, within reason.
 
You can use pencil lead grade as a good example. Like comparing a freshly sharpen HB vs a 2B pencil, you can use HB for a longer period before needing to resharpen.

If you want a extremely comparison, you can use 9H vs 9B.
 
Depends an how the person uses the knife. It might be a lot, but it could be they wouldn't notice a difference. Basically, there isnt as clear an answer as you might think. The biggest variable in knife performance is the user, and its a variable the maker has precious little control over.
 
Furious_Toast said:
Alright, so today I was having a conversation with a buddy of mine about blade steels and edge retention when he asked a question i couldn't answer. How much longer will certain steels hold an edge than your basic 420/440 $20 or cheaper walmart knife. So thats it, how much longer will 8cr13mov, 154cm, s30v, and s90v hold its edge than a very common cheap steel?

I know the retention is exponential but I couldn't give numbers or put it into perspective, and I didnt just want to make anything up.

Thanks and happy new year!
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When money is a factor it's very hard to convince someone who is used to those $20 knives to spend more than they are used to, it's almost impossible most of the time from what I have seen over the years.

Those low end budget knives sell for a reason, they are cheap and that is the bottom line.

8cr13mov is the same as 420J, very low end budget steel, lower than Bucks 420HC.

Keeping things simple.

The basic answer is a lot depending on the variables.

If they want actual numbers, well the best answer is it depends and it will get complicated in a real hurry, not the best way to go at 1st.

The easiest thing to do is look at the knives themselves and explain the quality differences as they will be apparent between those budget knives and ones in the $100 range so start there, the steel will be higher quality also in general.
 
Well, I don't think edge retention is the be all and end all for steel.

For instance, I find Buck's 420HC to be a very good steel for a budget knife. It holds an edge pretty well, sharpens very easily and gets razor sharp even if you are iffy in sharpening skills.

To me, easy of sharpening is more important than edge retention for any knife that isn't a bush knife or a work knife. For EDC purpose, 8cr13mov, or 420HC is a fine steel for most people.

Now if you are using a knife a lot for work purposes or may need if for survival purposes where you won't have access to proper sharpening equipment then it makes a lot more sense to get a super steel.

With that said, I do like no having to sharpen knives for a long time but some steels can be difficult to sharpen where as others are very easy to get a good edge on.
 
I'm the exact opposite.

All steels are easy to sharpen as I use diamonds. I'd rather get a great edge on a knife and be able to use it for a long time
 
mcrow said:
Well, I don't think edge retention is the be all and end all for steel.

For instance, I find Buck's 420HC to be a very good steel for a budget knife. It holds an edge pretty well, sharpens very easily and gets razor sharp even if you are iffy in sharpening skills.

To me, easy of sharpening is more important than edge retention for any knife that isn't a bush knife or a work knife. For EDC purpose, 8cr13mov, or 420HC is a fine steel for most people.

Now if you are using a knife a lot for work purposes or may need if for survival purposes where you won't have access to proper sharpening equipment then it makes a lot more sense to get a super steel.

With that said, I do like no having to sharpen knives for a long time but some steels can be difficult to sharpen where as others are very easy to get a good edge on.
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Super steels are trivial to put a good edge on with the proper sharpening tools, nothing really expensive either, simple ceramic rods, Silicon carbide Stones, Silicon Carbide loaded strop or Diamond stones will make very quick work of sharpening.

Normally in under a minute with just a few passes from getting dull to push cutting sharp depending on sharpening skill.

That's coming from someone who uses them on a daily basis, steels like S90V, S110V, 10V etc.
 
In terms of simple EDC tasks, let's say that a budget knife might lose it's edge in a few days to a week, and a knife in a higher end steel could last months before needing an actual sharpening.

For example, I had a knife in 3Cr steel get butter-knife dull before I could finish tearing down 1 box. I have another knife in Elmax that has kept it's edge all month, still push cutting receipt paper easily.
 
grownstar said:
In terms of simple EDC tasks, let's say that a budget knife might lose it's edge in a few days to a week, and a knife in a higher end steel could last months before needing an actual sharpening.

For example, I had a knife in 3Cr steel get butter-knife dull before I could finish tearing down 1 box. I have another knife in Elmax that has kept it's edge all month, still push cutting receipt paper easily.
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We use amazon prime all the time. I shred up boxes all the time. I don't want to sharpen constantly
 
The short answer is edge retention is how long it will hold a working edge for. Of course heat treatment, blade geometry, cutting material will play as a variables.

There is no chart that will show you how long an edge will last.
But you can compare edge retention between blade steels. But keep in mind of the above variables.
 
The next time someone sis you about edge retention, just tell them, the more expensive the knife the better the edge retention will be and leave it at that. I don't like explaining something to someone that doesn't have a clue to what is being said.
 
Edge retention has several components:

Wear resistance: the ability to retain a sharp apex when cutting abrasive materials. Generally, high-carbide powder steels will greatly increase wear resistance. Check out Anderson's thread to get actual numbers.

Resistance to rolling: Cutting hard materials can roll an edge. Generally, resistance to rolling and deformation is a function of strength, which itself is a function of hardness. Most high-hardness steels in the low to mid 60s Rc will resist edge rolling far better than soft steels in the 50s Rc.

Resistance to chipping, cracking and breaking, known as toughness. Lots of factors affect toughness, but usually softer steels and steels with lower carbide loads are tougher.

Geometry: Thinner geometry is often a huge asset in how long an edge will last, but a lot depends on what you are cutting. Anderson's thread has good information on this, too, with actual numbers. Thinner geometry is also easier to sharpen. The results you see in Anderson's epic thread are based on rope cutting. Those results will be different, sometimes a lot different, if you're cutting different kinds of material.

Edge stability is a combination of toughness and strength, but toughness and strength are usually at odds with each other -- increase one and reduce the other. There are steels processing techniques that can increase both, but the toughness steels are not likely to be the strongest steels. Edge stability requires a balance of toughness and strength that is the best balance for the material you are cutting.
 
So many variables:

HT.
HRC.
Profile.
Working edge or shaving sharp.
The list could be longer.

S30V (can have varrying degree's of egde retention based on who did the points I listed above)

I hate the whole 'edge retention' thing. How long do you need a steel to hold it's edge, and what properties are you willing to trade for that retention?
 
Twindog said:
Edge retention has several components:

Wear resistance: the ability to retain a sharp apex when cutting abrasive materials. Generally, high-carbide powder steels will greatly increase wear resistance. Check out Anderson's thread to get actual numbers.

Resistance to rolling: Cutting hard materials can roll an edge. Generally, resistance to rolling and deformation is a function of strength, which itself is a function of hardness. Most high-hardness steels in the low to mid 60s Rc will resist edge rolling far better than soft steels in the 50s Rc.

Resistance to chipping, cracking and breaking, known as toughness. Lots of factors affect toughness, but usually softer steels and steels with lower carbide loads are tougher.

Geometry: Thinner geometry is often a huge asset in how long an edge will last, but a lot depends on what you are cutting. Anderson's thread has good information on this, too, with actual numbers. Thinner geometry is also easier to sharpen. The results you see in Anderson's epic thread are based on rope cutting. Those results will be different, sometimes a lot different, if you're cutting different kinds of material.

Edge stability is a combination of toughness and strength, but toughness and strength are usually at odds with each other -- increase one and reduce the other. There are steels processing techniques that can increase both, but the toughness steels are not likely to be the strongest steels. Edge stability requires a balance of toughness and strength that is the best balance for the material you are cutting.
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You did such a better job at explaining......thank you.
 
mcrow said:
Well, I don't think edge retention is the be all and end all for steel.

For instance, I find Buck's 420HC to be a very good steel for a budget knife. It holds an edge pretty well, sharpens very easily and gets razor sharp even if you are iffy in sharpening skills.

To me, easy of sharpening is more important than edge retention for any knife that isn't a bush knife or a work knife. For EDC purpose, 8cr13mov, or 420HC is a fine steel for most people.

Now if you are using a knife a lot for work purposes or may need if for survival purposes where you won't have access to proper sharpening equipment then it makes a lot more sense to get a super steel.

With that said, I do like no having to sharpen knives for a long time but some steels can be difficult to sharpen where as others are very easy to get a good edge on.
Click to expand...
I was thinking about if a super steel would be better to have in a survival situation. Yes the longer the edge holds the better BUT eventually any knife will get dull and I'd rather be stuck in the woods with dull 420HC than S110V. Reason being I may be able to sharpen the 420 on found items like rocks or possibly a broken coffee mug laying around or something. Ideally you'd have a pocket diamond sharpener in any survival situation but if it came up out of nowhere I'd rather be stuck with the dull softer steel than the dull harder steel. I could be wrong I hope I never have to find out
 
ak585479 said:
I was thinking about if a super steel would be better to have in a survival situation. Yes the longer the edge holds the better BUT eventually any knife will get dull and I'd rather be stuck in the woods with dull 420HC than S110V. Reason being I may be able to sharpen the 420 on found items like rocks or possibly a broken coffee mug laying around or something. Ideally you'd have a pocket diamond sharpener in any survival situation but if it came up out of nowhere I'd rather be stuck with the dull softer steel than the dull harder steel. I could be wrong I hope I never have to find out
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Well, the issue would be that 420HC isn't as durable as the steels typically used for survival knives. 420HC is more likely to break than 1095 for instance.
 
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