Dividing line: Ease of sharpening and edge holding

[Doc Dan]

Is there a consensus of where the dividing line between ease of sharpening and edge retention lies on a Spyderco factory standard production knife?

This is complicated, I know. Heat treatment, carbides, and so much more go into the equation. That's why I chose standard production knives. I know some people have a high tolerance and a love of sharpening, while others don't have time. What steels seem to give the average best balance nowadays?

[Coastal]

I find K390 surprisingly easy to sharpen. If sharpening and edge holding are the figures of merit, K390 is it.

Full disclosure, I use TSPROF and Spyderco diamond stones on all steels.

[Stirmos]

I’d like to add the dimension ‘edge taking’, which may make it even more complex and very subjective.

In real world use, with some solid diamond stones I don’t find much difference in sharpening Maxamet/REX 121 or any other well heat treated steel.
However, the ability to allow for different edge angles and fine edge taking is a world apart. SPY27, REX45, REX 76, CruWear are examples of steels that take any edge and hold them from decent to great. A polished edge on a low angle, course edge on a higher angle, whatever.
And a touch of a strop with proper compound is enough to bring the edge back in seconds.
Some steels make real world sharpening, and the options that work well, more restrictive.

Something like Maxamet keeps a forever working edge after finishing on a 400 grit diamond stone, but lowering the edge angle or finishing on a fine stone hasn’t given me much pleasure at all.

And I like to have at least some knives with a low edge angle and finer finish, for ultimate slicing.
That again is a preference, and depends on what to cut with it.

[kobold]

Not having detailed HRC data leaves us in the dark.. but i think in general, nothing cuts for so long and nothing is as easy to sharpen as SEs.

[vivi]

Is there a consensus of where the dividing line between ease of sharpening and edge retention lies on a Spyderco factory standard production knife?

This is complicated, I know. Heat treatment, carbides, and so much more go into the equation. That's why I chose standard production knives. I know some people have a high tolerance and a love of sharpening, while others don't have time. What steels seem to give the average best balance nowadays?

both ease of sharpening and edge holding are HIGHLY dependent on how one sharpens, and how one uses / abuses their cutting tools.

I can make a Kiwi chef knife hold a workable edge for 6 months with no touch-up at home.

The same knife will be lucky to be functional 2 weeks out if I leave it at work, where people mistreat the house knives. That's why I keep the good stuff in my knife roll and take that home after every shift.

Lots of folks are missing out on edge retention based on how they report sharpening here.

I recently shared some videos on this post - viewtopic.php?p=1845456#p1845456

The lead video shows one of my most used machetes, made out of soft carbon steel (1055 I think) with low edge stability used for tough chopping and batoning tasks. I sharpen it thinner than some people here sharpen their pocket knives.

Manix XL doing light chopping,batoning and cutting cans with a ~10dps edge, zero issues.

10dps edged Pacific Salts with a coarse finish showing tremendous edge holding.

So, depending on how you sharpen, user A can get 4-8x the edge holding as user B.

General rule of thumb is thinner, coarser edges out last thicker, polished edges.....but there's a time and place for every edge type. I wouldn't put the same edge on a 62rc petty knife as a 54rc splitting maul.

the differences possible by tweaking edge geometry, edge finish and primary grind geometry are generally bigger than the differences between steels, unless you go to extremes, e.g. 420j2 gas station knife vs maxamet.

[derangedhermit]

Is there a consensus of where the dividing line between ease of sharpening and edge retention lies on a Spyderco factory standard production knife?

This is complicated, I know. Heat treatment, carbides, and so much more go into the equation. That's why I chose standard production knives. I know some people have a high tolerance and a love of sharpening, while others don't have time. What steels seem to give the average best balance nowadays?

both ease of sharpening and edge holding are HIGHLY dependent on how one sharpens, and how one uses / abuses their cutting tools.

I can make a Kiwi chef knife hold a workable edge for 6 months with no touch-up at home.

The same knife will be lucky to be functional 2 weeks out if I leave it at work, where people mistreat the house knives. That's why I keep the good stuff in my knife roll and take that home after every shift.

Lots of folks are missing out on edge retention based on how they report sharpening here.

I recently shared some videos on this post - viewtopic.php?p=1845456#p1845456

The lead video shows one of my most used machetes, made out of soft carbon steel (1055 I think) with low edge stability used for tough chopping and batoning tasks. I sharpen it thinner than some people here sharpen their pocket knives.

Manix XL doing light chopping,batoning and cutting cans with a ~10dps edge, zero issues.

10dps edged Pacific Salts with a coarse finish showing tremendous edge holding.

So, depending on how you sharpen, user A can get 4-8x the edge holding as user B.

General rule of thumb is thinner, coarser edges out last thicker, polished edges.....but there's a time and place for every edge type. I wouldn't put the same edge on a 62rc petty knife as a 54rc splitting maul.

the differences possible by tweaking edge geometry, edge finish and primary grind geometry are generally bigger than the differences between steels, unless you go to extremes, e.g. 420j2 gas station knife vs maxamet.

I agree. Aside from splitting mauls, isn't it generally true that for pocket knives, less than 15dps is generally superior for ease of cutting and edge holding, while most folding knives come from the factory with 15-20dps? Maybe there is a meaningful steel-dependent difference, maybe not. It is so important it is worth at least discussion.

I wonder if there is a market opportunity for Spyderco in reviewing, modifying where needed, and emphasizing fact-based factory sharpening choices as a dominant factor in how well Spydercos cut compared to the competition?

[Deadboxhero]

Not having detailed HRC data leaves us in the dark.. but i think in general, nothing cuts for so long and nothing is as easy to sharpen as SEs.

HRC can be misleading.

The microstructure making up that HRC is not all the same hardness, it's the sum of all its parts.

Microstructure is King.

[Doc Dan]

Is there a consensus of where the dividing line between ease of sharpening and edge retention lies on a Spyderco factory standard production knife?

This is complicated, I know. Heat treatment, carbides, and so much more go into the equation. That's why I chose standard production knives. I know some people have a high tolerance and a love of sharpening, while others don't have time. What steels seem to give the average best balance nowadays?

both ease of sharpening and edge holding are HIGHLY dependent on how one sharpens, and how one uses / abuses their cutting tools.

I can make a Kiwi chef knife hold a workable edge for 6 months with no touch-up at home.

The same knife will be lucky to be functional 2 weeks out if I leave it at work, where people mistreat the house knives. That's why I keep the good stuff in my knife roll and take that home after every shift.

Lots of folks are missing out on edge retention based on how they report sharpening here.

I recently shared some videos on this post - viewtopic.php?p=1845456#p1845456

The lead video shows one of my most used machetes, made out of soft carbon steel (1055 I think) with low edge stability used for tough chopping and batoning tasks. I sharpen it thinner than some people here sharpen their pocket knives.

Manix XL doing light chopping,batoning and cutting cans with a ~10dps edge, zero issues.

10dps edged Pacific Salts with a coarse finish showing tremendous edge holding.

So, depending on how you sharpen, user A can get 4-8x the edge holding as user B.

General rule of thumb is thinner, coarser edges out last thicker, polished edges.....but there's a time and place for every edge type. I wouldn't put the same edge on a 62rc petty knife as a 54rc splitting maul.

the differences possible by tweaking edge geometry, edge finish and primary grind geometry are generally bigger than the differences between steels, unless you go to extremes, e.g. 420j2 gas station knife vs maxamet.

Yes, the angle is actually more important than the steel, but all things being equal, what steel has that balance?

[Doc Dan]

Not having detailed HRC data leaves us in the dark.. but i think in general, nothing cuts for so long and nothing is as easy to sharpen as SEs.

HRC can be misleading.

The microstructure making up that HRC is not all the same hardness, it's the sum of all its parts.

Microstructure is King.

I am no expert in this, but I respect your input. I know different elements harden in different ways and hardnesses. I wonder if simple steels are sometimes better than complex steels in this regard?
Also, to your point, how does one overcome the issues with the microstructure not all being the same hardness? I would think that there could be some problems associated with that. (not just asking...researching)

[Deadboxhero]

Not having detailed HRC data leaves us in the dark.. but i think in general, nothing cuts for so long and nothing is as easy to sharpen as SEs.

HRC can be misleading.

The microstructure making up that HRC is not all the same hardness, it's the sum of all its parts.

Microstructure is King.

I am no expert in this, but I respect your input. I know different elements harden in different ways and hardnesses. I wonder if simple steels are sometimes better than complex steels in this regard?
Also, to your point, how does one overcome the issues with the microstructure not all being the same hardness? I would think that there could be some problems associated with that. (not just asking...researching)

It's not a matter of making it all perfectly homogeneous since the steel fundamentally has a composite nature to it.

For example, look at the human body, it has a complex composite of different tissues doing different things.

You can't have them all be one tissue type to maximize performance.

We also can't use a bathroom scale (HRC) to measure body composition.

It's the same reason why you can take two athletes who both weigh 200lb (62-63rc) and you can get very different performance metrics from them despite the fact they both weigh (HRC) the same.

Why? Well, their body composition is not the same.


Simple steels can have the same problems that all steels can have if HRC is the only metric used to measure properties.

In fact, it might even be worse since a lot of makers don't even put in a lot of effort needed because they think that it's "simple" and that it got "hard enough to skate a file"

Meanwhile, their edge is riddled with soft pearlite colonies making the edge retention and sharpenability horrific.

[kobold]

So then we need also a micrograph and dive into stuff such as this?
https://www.phase-trans.msm.cam.ac.uk/2 ... re/SM.html
Not sure how many will do it..

[Evil D]

Diamonds go a long way to leveling this playing field. I don't look at this as a matter of difficulty anymore, it's more like one just takes a little more time than the next due to being more/less easy to grind. I think probably the common mistake a lot of people make is not dropping down to a course enough edge when sharpening, and the idea that you can simply touch up an edge all of the time is just not always true. Or to put it another way, you're making it more difficult and time consuming than it has to be because you're expecting to sharpen your edge with too high grit or the wrong media entirely. Some of the steels will technically be cut by a ceramic stone but it's on such a small level that you're closer to burnishing than you are cutting and then your touch up is more like steeling an edge straight and then there goes your edge retention too. People also don't talk enough about destressing their edge before sharpening, you need to get rid of all that old fatigued steel and cut a new apex. Think about how many times you can bend a metal coat hanger before it eventually breaks, the same thing happens to an edge as you dull it and touch it up on high grit media or strop it back to sharp. Eventually you need to remove that old steel and start fresh with a new apex. Edges are perishable.

[Stirmos]

We also can't use a bathroom scale (HRC) to measure body composition.

It's the same reason why you can take two athletes who both weigh 200lb (62-63rc) and you can get very different performance metrics from them despite the fact they both weigh (HRC) the same.

Why? Well, their body composition is not the same.

Simple steels can have the same problems that all steels can have if HRC is the only metric used to measure properties.

Thanks for sharing, learning a lot here.

In the end HRC is just a measurable indication, and not the key aspect.

However, assuming optimal heat treatment, there is a noticeable difference between different HRC values often.
When equally well heat treated (if technically even possible). A higher HRC can increase edge retention on certain materials significantly. Especially high abrasive and softer (e.g. cardboard) seem to benefit. Where with harder less abrasive materials (e.g. hardwood, hardplastic, nylon rope) a lower HRC can be beneficial. Saving the edge from damage over time.

This is only partially shown with CATRA tests, since the type of material being cut may largely determine the edge retention in practice given a certain HRC.

Hence, we need fully stainless/endlessly though/72 HRC/easily sharpenable/affordable steels with more vanadium and tungsten than our pockets can carry .
No perfect solution, and I agree proper heat treatment is what makes a steel shine in day-to-day practice. Often maximizing easy of sharpening/edge retention/edge stability in a wide range of applications.

[Brock O Lee]

Diamonds go a long way to leveling this playing field. I don't look at this as a matter of difficulty anymore, it's more like one just takes a little more time than the next due to being more/less easy to grind. I think probably the common mistake a lot of people make is not dropping down to a course enough edge when sharpening, and the idea that you can simply touch up an edge all of the time is just not always true. Or to put it another way, you're making it more difficult and time consuming than it has to be because you're expecting to sharpen your edge with too high grit or the wrong media entirely. Some of the steels will technically be cut by a ceramic stone but it's on such a small level that you're closer to burnishing than you are cutting and then your touch up is more like steeling an edge straight and then there goes your edge retention too. People also don't talk enough about destressing their edge before sharpening, you need to get rid of all that old fatigued steel and cut a new apex. Think about how many times you can bend a metal coat hanger before it eventually breaks, the same thing happens to an edge as you dull it and touch it up on high grit media or strop it back to sharp. Eventually you need to remove that old steel and start fresh with a new apex. Edges are perishable.

Amen brother.

[Doc Dan]

Not having detailed HRC data leaves us in the dark.. but i think in general, nothing cuts for so long and nothing is as easy to sharpen as SEs.

HRC can be misleading.

The microstructure making up that HRC is not all the same hardness, it's the sum of all its parts.

Microstructure is King.

I am no expert in this, but I respect your input. I know different elements harden in different ways and hardnesses. I wonder if simple steels are sometimes better than complex steels in this regard?
Also, to your point, how does one overcome the issues with the microstructure not all being the same hardness? I would think that there could be some problems associated with that. (not just asking...researching)

It's not a matter of making it all perfectly homogeneous since the steel fundamentally has a composite nature to it.

For example, look at the human body, it has a complex composite of different tissues doing different things.

You can't have them all be one tissue type to maximize performance.

We also can't use a bathroom scale (HRC) to measure body composition.

It's the same reason why you can take two athletes who both weigh 200lb (62-63rc) and you can get very different performance metrics from them despite the fact they both weigh (HRC) the same.

Why? Well, their body composition is not the same.


Simple steels can have the same problems that all steels can have if HRC is the only metric used to measure properties.

In fact, it might even be worse since a lot of makers don't even put in a lot of effort needed because they think that it's "simple" and that it got "hard enough to skate a file"

Meanwhile, their edge is riddled with soft pearlite colonies making the edge retention and sharpenability horrific.

Thanks! Man, you should write a book. You have a knack for making things easy to understand. PM me and I'll tell you.

[vivi]

Diamonds go a long way to leveling this playing field. I don't look at this as a matter of difficulty anymore, it's more like one just takes a little more time than the next due to being more/less easy to grind. I think probably the common mistake a lot of people make is not dropping down to a course enough edge when sharpening, and the idea that you can simply touch up an edge all of the time is just not always true. Or to put it another way, you're making it more difficult and time consuming than it has to be because you're expecting to sharpen your edge with too high grit or the wrong media entirely. Some of the steels will technically be cut by a ceramic stone but it's on such a small level that you're closer to burnishing than you are cutting and then your touch up is more like steeling an edge straight and then there goes your edge retention too. People also don't talk enough about destressing their edge before sharpening, you need to get rid of all that old fatigued steel and cut a new apex. Think about how many times you can bend a metal coat hanger before it eventually breaks, the same thing happens to an edge as you dull it and touch it up on high grit media or strop it back to sharp. Eventually you need to remove that old steel and start fresh with a new apex. Edges are perishable.

yep. I always advise against people stropping back a dulled edge, or relying on them for deburring.

if you are going to strop, do just a few passes as the finishing step.

I can bring an edge back in less than 30 seconds with medium sharpmaker rods, so I'm not sure why some are so big on stropping things back. it tends to create a more rounded edge that lasts less than one off stones....for me at least.

even medium sharpmaker rods, specifically mine I ground down extra coarse, sometimes aren't enough.

every few touch-ups I refresh the edge and remove the microbevel if applicable on an 80-300 grit diamond plate, then finish with one or two strokes per side on the medium rods or my medium stone.

did this to a super blue gyuto last night. in the first picture you can see the bevel was clouey since I just touched up the apex on my medium bench stone for a few months. Refreshed the edge (poorly, I was rushing) on a 300 grit diamond plate, then finished on the same medium stone.




The edge turned out much better and more aggressive than the medium stone touch ups was resulting in.

funny side story. new guy at work took over prepping some peppers for me, then I had him dice some fresh mozz. between tasks I took this knife back and cleaned it and out it in my knife roll and gave him a kom kom chef knife. he asked, "different knives for different foods?" I said "no, $200 knife vs $10 knife. I'd be a lot less upset if you messed up this one "

[RustyIron]

This is complicated, I know. Heat treatment, carbides, and so much more go into the equation. That's why I chose standard production knives. I know some people have a high tolerance and a love of sharpening, while others don't have time. What steels seem to give the average best balance nowadays?

It's not been my experience that sharpening is complicated by the use of non-production steels. In fact, I'd go so far as to say that some of Spyderco's "fancier" steels are both easier to sharpen and hold a better edge than some of their standard steels.

If you don't have time to sharpen your knives, Spyderco will do it for free. You just pay the shipping. But unless you live above the post office, you can probably sharpen the knife in less time than it takes to ship it.

[Spyderfreek]

Nothing is hard to sharpen if you use diamonds, the exception being maybe Maxamet or Rex 121. Both of those require care to avoid chipping when sharpening, and you can't use very coarse stones to apex. Steels like Maxamet and Rex 121 take a long time to reprofile the edge, but once you've hit the apex it takes very little effort to keep it sharp with fine stones.

[zhyla]

Diamonds go a long way to leveling this playing field.

This. I feel like the “ease of sharpening” thing getting repeated these days was very true 10 years ago but diamond “plates” (the cheap thin ones) have gotten so cheap and people don’t know it I guess.

[toml4185]

I'm pretty sure that SPY27 was created precisely to walk this tightrope.

Personally, I love it.