Taking steel to its maximum potentials
Posted by cKc (Kyley Harris)
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Taking steel to its maximum potentials January 27, 2022 12:04AM |
Admin Registered: 2 years ago Posts: 147 |
I have been resurrecting some of my old videos that i'd made private.
This one i wanted to post here purely as an example for any knifemakers who might end up seeing this.
this is O1, triple tempered to 61rc +/-
we live in an age where people are taking steels to extremes, going for harder and harder steels, higher and higher carbide content, all for edge retention. but many are ignoring that geometry is the dominating factor in these things.
a similarly hard simple steel with a fine geometry will blow away a high carbide with a poor geometry, or at least equalize edge retention but give a superior cutting experience with lower force.
the best advantage to a harder stronger tougher steel is the ability to make it thinner and thinner while retaining enough stability to cut without damage.
this knife is distal tapered, not profile tapered. starting 0.040" down to 0.013" on the spine. the edge BTE can only be approximated. the edge itself is sub 0.002" but if looking at the height of a normal factory bevel of 15-20dps being 0.020 behind the edge.. well you cant even compare.
it goes from about 0,005 to 0.002" down the blade. bear in mind its only 0.013 at the spine.. the video is more clear. this is just a summary.
the point of putting this back is really to ask makers to challenge themselves. even on hard use outdoor blades, you can easily go 0.001 - 0.005" edges with full flat or convex grinds. you just increase the spine thickness to create the support structure, or reduce the grind height to ensure that you are getting 3-7dps primary bevels down to the 0.005" area.
This one i wanted to post here purely as an example for any knifemakers who might end up seeing this.
this is O1, triple tempered to 61rc +/-
we live in an age where people are taking steels to extremes, going for harder and harder steels, higher and higher carbide content, all for edge retention. but many are ignoring that geometry is the dominating factor in these things.
a similarly hard simple steel with a fine geometry will blow away a high carbide with a poor geometry, or at least equalize edge retention but give a superior cutting experience with lower force.
the best advantage to a harder stronger tougher steel is the ability to make it thinner and thinner while retaining enough stability to cut without damage.
this knife is distal tapered, not profile tapered. starting 0.040" down to 0.013" on the spine. the edge BTE can only be approximated. the edge itself is sub 0.002" but if looking at the height of a normal factory bevel of 15-20dps being 0.020 behind the edge.. well you cant even compare.
it goes from about 0,005 to 0.002" down the blade. bear in mind its only 0.013 at the spine.. the video is more clear. this is just a summary.
the point of putting this back is really to ask makers to challenge themselves. even on hard use outdoor blades, you can easily go 0.001 - 0.005" edges with full flat or convex grinds. you just increase the spine thickness to create the support structure, or reduce the grind height to ensure that you are getting 3-7dps primary bevels down to the 0.005" area.
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Re: Taking steel to its maximum potentials January 27, 2022 12:20AM |
Registered: 2 years ago Posts: 256 |
It really would be interesting to see a manufacturer put the same money and energy spent towards the high carbide steels into a simple steel, excellent heat treatment, and thin geometry. They could probably break even in costs but the knife might be much better suited to most uses. S90V was interesting enough to me to buy a knife in it for purposes of seeing what, if any, difference I can actually detect compared to VG-10 or S30V, but aside from just curiosity I would really prefer the more simple steels for most work.
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Re: Taking steel to its maximum potentials January 27, 2022 02:54AM |
Admin Registered: 2 years ago Posts: 147 |
i think that the spyderco K390 models coming out now are possibly one of the best examples of a "super steel' done right
k390 thread spyderco forum
people are getting 64-66rc on tests which falls in line with expected variances between different machines..
this is a steel that should be capable of going much much thinner than spyderco is taking it. its just too hard for a factory to do near zero edges.. but anyone with a 1x30 should be able to thin these down easily.
this is an example of what a good grind on that steel looks like. depending on uses, there is no question it could go even lower.
BBB is doing full flat here to 005 and 15dps, so this is still a very durable knife. on that steel i personally would be comfortable taking it to
12dps.
there are other options too. instead of going to full flat like that, it could be taken full flat leading to a 7dps bevel and a 12-15dps edge bevel of around 0.003 which would be a dream knife for me.
it comes down to how you use knives. if my victorinox paring knife can be that thin and cut cardboards and plastics, then k390 will do it easily.
look at how he is treating this knife.. and its fine.. this shows that for a conservative knife user who cares about cutting performance this can go way way thinner. this video is a very entertaining and very good explanation of what knives should be
Edited 1 time(s). Last edit at 01/27/2022 03:00AM by cKc (Kyley Harris).
k390 thread spyderco forum
people are getting 64-66rc on tests which falls in line with expected variances between different machines..
this is a steel that should be capable of going much much thinner than spyderco is taking it. its just too hard for a factory to do near zero edges.. but anyone with a 1x30 should be able to thin these down easily.
this is an example of what a good grind on that steel looks like. depending on uses, there is no question it could go even lower.
BBB is doing full flat here to 005 and 15dps, so this is still a very durable knife. on that steel i personally would be comfortable taking it to
12dps.
there are other options too. instead of going to full flat like that, it could be taken full flat leading to a 7dps bevel and a 12-15dps edge bevel of around 0.003 which would be a dream knife for me.
it comes down to how you use knives. if my victorinox paring knife can be that thin and cut cardboards and plastics, then k390 will do it easily.
look at how he is treating this knife.. and its fine.. this shows that for a conservative knife user who cares about cutting performance this can go way way thinner. this video is a very entertaining and very good explanation of what knives should be
Edited 1 time(s). Last edit at 01/27/2022 03:00AM by cKc (Kyley Harris).
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Re: Taking steel to its maximum potentials January 27, 2022 04:33AM |
Registered: 2 years ago Posts: 256 |
K390 is one I haven’t bothered to look into, I just sort of wrote it off as another duper steel. But apparently I was wrong, I mean if the hardness is in the same range as ZDP-189 but the carbide size/aggregates are much smaller than typical chromium carbides then that might be an excellent steel. Similar to M2/M4 where the toughness is relatively high for the carbide volume. I’ll have to pick one of those up soon, probably the Police Lightweight.
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Re: Taking steel to its maximum potentials January 27, 2022 06:06PM |
Registered: 2 years ago Posts: 36 |
Quote
cKc (Kyley Harris)
I have been resurrecting some of my old videos that i'd made private.
This one i wanted to post here purely as an example for any knifemakers who might end up seeing this.
this is O1, triple tempered to 61rc +/-
we live in an age where people are taking steels to extremes, going for harder and harder steels, higher and higher carbide content, all for edge retention. but many are ignoring that geometry is the dominating factor in these things.
a similarly hard simple steel with a fine geometry will blow away a high carbide with a poor geometry, or at least equalize edge retention but give a superior cutting experience with lower force.
the best advantage to a harder stronger tougher steel is the ability to make it thinner and thinner while retaining enough stability to cut without damage.
this knife is distal tapered, not profile tapered. starting 0.040" down to 0.013" on the spine. the edge BTE can only be approximated. the edge itself is sub 0.002" but if looking at the height of a normal factory bevel of 15-20dps being 0.020 behind the edge.. well you cant even compare.
it goes from about 0,005 to 0.002" down the blade. bear in mind its only 0.013 at the spine.. the video is more clear. this is just a summary.
the point of putting this back is really to ask makers to challenge themselves. even on hard use outdoor blades, you can easily go 0.001 - 0.005" edges with full flat or convex grinds. you just increase the spine thickness to create the support structure, or reduce the grind height to ensure that you are getting 3-7dps primary bevels down to the 0.005" area.
Amazing work,
Do you know if the same geometry will be feasible with an higher alloyed steel?
I know that theorically the strength could be much higher at the same hardness, but wouldn't the drop in toughness be very relevant because of the low stiffness of the blade?
I have almost no experience with high carbide steel, I almost always used simple carbon steel or stainless up to XHP, I always had the impression they require more time and effort to work with to only gain a slightly higher edge retention cutting abrasive material, but I can be totally wrong I assume.
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Re: Taking steel to its maximum potentials February 01, 2022 03:03AM |
Admin Registered: 2 years ago Posts: 147 |
Quote
Millscale
I have been resurrecting some of my old videos that i'd made private.
This one i wanted to post here purely as an example for any knifemakers who might end up seeing this.
this is O1, triple tempered to 61rc +/-
we live in an age where people are taking steels to extremes, going for harder and harder steels, higher and higher carbide content, all for edge retention. but many are ignoring that geometry is the dominating factor in these things.
a similarly hard simple steel with a fine geometry will blow away a high carbide with a poor geometry, or at least equalize edge retention but give a superior cutting experience with lower force.
the best advantage to a harder stronger tougher steel is the ability to make it thinner and thinner while retaining enough stability to cut without damage.
this knife is distal tapered, not profile tapered. starting 0.040" down to 0.013" on the spine. the edge BTE can only be approximated. the edge itself is sub 0.002" but if looking at the height of a normal factory bevel of 15-20dps being 0.020 behind the edge.. well you cant even compare.
it goes from about 0,005 to 0.002" down the blade. bear in mind its only 0.013 at the spine.. the video is more clear. this is just a summary.
the point of putting this back is really to ask makers to challenge themselves. even on hard use outdoor blades, you can easily go 0.001 - 0.005" edges with full flat or convex grinds. you just increase the spine thickness to create the support structure, or reduce the grind height to ensure that you are getting 3-7dps primary bevels down to the 0.005" area.
Amazing work,
Do you know if the same geometry will be feasible with an higher alloyed steel?
I know that theorically the strength could be much higher at the same hardness, but wouldn't the drop in toughness be very relevant because of the low stiffness of the blade?
I have almost no experience with high carbide steel, I almost always used simple carbon steel or stainless up to XHP, I always had the impression they require more time and effort to work with to only gain a slightly higher edge retention cutting abrasive material, but I can be totally wrong I assume.
More than possible. As knifemakers, looking at the works of Roman Landes would be important in determining what a steel can handle in edge stablity.. all steels in thin cross sections will flex, which is how bandsaws work even at very high hardnesses. the issue with high alloy steel will not be how thin you can grind it, but how thin the actual apex is. you need to look at the aggregate size in microns of the steel you are using, and use an edge angle that will be large enough to contain those aggregates and not have a lot of flaking or tear out.
but most high alloy steels will hold 12dps easily.. but maybe not 6 - 10dps. everything in the knife world is overbuilt with warranty in mind, rather than built well with User accountability in mind.
I'm not really into high alloyed steels. i personally find that with the steels i use, i can regrind damage or resharpen in seconds or minutes on knives is preferrable, and im still taking steels thinner than most imagine which means my edge longevity is much higher than most using high alloyed steels.
BBB knives loves these high alloys and is doing a good job showing that they can go thin with good heat treatments. you can see the thinness and flex of the edge here is handled with no issue at all... now if BBB just took this knife and ground off all the spine thickness in a distal taper so that it was the same thickness at the top as it is 0.100 from the apex, then you would have a high edge stability, very flexible knife.
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Re: Taking steel to its maximum potentials February 01, 2022 03:26AM |
Admin Registered: 2 years ago Posts: 147 |
i found an old video of one of my knives by John Davis. it was sent to him to try because he was doing a lot of testing and I and some others felt he'd never really tried a thin knife. the irony here is that its 5mm thick spine. but the edge is much thinner than any production knife.
John to a lot of flak when he did knifemaking and made some mistakes, which was sad, because he is genuinely a nice guy that did some good videos and research.. that doesn't detract from the videos he put out and still has.
performance apex doesn't require a thin spine. this convex is probably around 7dps or less on the apex with just a subtle micro bevel raising it up
His commentary as cutting in this video is a good commentary on seeing someone doing a lot of cutting test finally trying something with a good thin geometry..
John to a lot of flak when he did knifemaking and made some mistakes, which was sad, because he is genuinely a nice guy that did some good videos and research.. that doesn't detract from the videos he put out and still has.
performance apex doesn't require a thin spine. this convex is probably around 7dps or less on the apex with just a subtle micro bevel raising it up
His commentary as cutting in this video is a good commentary on seeing someone doing a lot of cutting test finally trying something with a good thin geometry..
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Re: Taking steel to its maximum potentials February 01, 2022 03:36AM |
Admin Registered: 2 years ago Posts: 499 |
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Re: Taking steel to its maximum potentials February 02, 2022 08:59PM |
Registered: 2 years ago Posts: 36 |
CkC,
Thank your for the explanation, was very clear and it also reminded me something Cliff said in one of his videos.
It is sad indeed that most of the knife manufacturers have no interest in producing blades optimized for cutting, holding a keen edge or reducing cutting strain and instead steel choice is presented as the one and only way to go, only to convince you that your tools are suddenly not up to a certain standard, and you need to buy more to keep up, and also I believe that knives in general are becoming more and more a luxury item, I keep seeing rewievs evaluating absolutely immaculate knives hardly been used for abything but cutting loose threads and opening mail
Geometry is certainly what cutting is about, but saying "hey, reduce your edge angle to improve edge retention" doesn't sell a new knife I guess
Sorry for the rant, I guess I had a bad day at work
Thank you all for sharing your knowledge
Edited 1 time(s). Last edit at 02/02/2022 09:01PM by Millscale.
Thank your for the explanation, was very clear and it also reminded me something Cliff said in one of his videos.
It is sad indeed that most of the knife manufacturers have no interest in producing blades optimized for cutting, holding a keen edge or reducing cutting strain and instead steel choice is presented as the one and only way to go, only to convince you that your tools are suddenly not up to a certain standard, and you need to buy more to keep up, and also I believe that knives in general are becoming more and more a luxury item, I keep seeing rewievs evaluating absolutely immaculate knives hardly been used for abything but cutting loose threads and opening mail
Geometry is certainly what cutting is about, but saying "hey, reduce your edge angle to improve edge retention" doesn't sell a new knife I guess
Sorry for the rant, I guess I had a bad day at work
Thank you all for sharing your knowledge
Edited 1 time(s). Last edit at 02/02/2022 09:01PM by Millscale.
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Re: Taking steel to its maximum potentials February 02, 2022 10:08PM |
Admin Registered: 2 years ago Posts: 499 |
Quote
Millscale
CkC,
Thank your for the explanation, was very clear and it also reminded me something Cliff said in one of his videos.
It is sad indeed that most of the knife manufacturers have no interest in producing blades optimized for cutting, holding a keen edge or reducing cutting strain and instead steel choice is presented as the one and only way to go, only to convince you that your tools are suddenly not up to a certain standard, and you need to buy more to keep up, and also I believe that knives in general are becoming more and more a luxury item, I keep seeing rewievs evaluating absolutely immaculate knives hardly been used for abything but cutting loose threads and opening mail
Geometry is certainly what cutting is about, but saying "hey, reduce your edge angle to improve edge retention" doesn't sell a new knife I guess
Sorry for the rant, I guess I had a bad day at work
Thank you all for sharing your knowledge
Millscale,
This is why a lot of us have been getting Spyderco's, Opinels, some Benchmades, Herder Windmill Knives, etc. If you have access to a 1x30" or money and space to but a 1x30", you can basically regrind a knife to cut like a knife should cut, if you ask me.
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Re: Taking steel to its maximum potentials February 05, 2022 08:09PM |
Registered: 2 years ago Posts: 36 |
Jasonstone20, that would be awesome,
but I buy very few knives per year (right now I actually have way more sharpening stones than knives, funny) and I tend to stay away from hard to grind steel, so I usually bite the bullet and grind the primary with a good old coarse Sic stone, time consuming, yes, but I actually enjoy sharpening quite a lot, doesn't seem totally a waste of time.
Carbon steel I grind and profile with good files, they seem to keep working even using them regularly on hardened steel, so far so good
Also, I am afraid of heat buildup during grinding, knives for me are an hobby, so manual equipment are what I feel I need at the moment; maybe next year I will change my mind, who knows
but I buy very few knives per year (right now I actually have way more sharpening stones than knives, funny) and I tend to stay away from hard to grind steel, so I usually bite the bullet and grind the primary with a good old coarse Sic stone, time consuming, yes, but I actually enjoy sharpening quite a lot, doesn't seem totally a waste of time.
Carbon steel I grind and profile with good files, they seem to keep working even using them regularly on hardened steel, so far so good
Also, I am afraid of heat buildup during grinding, knives for me are an hobby, so manual equipment are what I feel I need at the moment; maybe next year I will change my mind, who knows
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Re: Taking steel to its maximum potentials February 06, 2022 08:50AM |
Admin Registered: 2 years ago Posts: 147 |
Quote
Millscale
,
but I buy very few knives per year (right now I actually have way more sharpening stones than knives, funny) and I tend to stay away from hard to grind steel,
same. actually.. i have already bought too many new knives. while it is nice to sample a bunch of different knives, i really think that my ultimate preference is to have a small range of knives for different activities and use those to maximum effect and learn those knives and enjoy them.
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