Blade Steel Rehardening

[Murphyslaw]

That AUS-8A sounds like a great idea. The before-and-after can be directly compared. Cool.

COTDT,

I would also suggest that after your reheat treat, that both the treated and untreated knives be sent to one of the members here for sharpenning (my dime) so that we are comparing apples to apples. We could also circulate the knives for blind testing to a few members, who would post reviews.

Watcha think?

Chris

 

[FlaMtnBkr]

I don't understand this thread. There is nothing an individual can do to the heat treatment of a purchasezd blade except ruin it. This seems like a bizarre idea to me -- an unworkable solution desperately searching for a nonexistent problem to solve.

One person already dirtied up the thread saying essentially what you just did. Any particular reason you felt the need to restate those somewhat ignorant claims? Especially after they had been addressed by multiple members?

If you have a question or valid argument that is one thing. But to just come into someone's thread and say the only possible outcome is bad and is pretty much a stupid idea is somewhat trollish in my book. And it has happened twice already by established members. I'm not trying to be negative at all just curious why it's happening?

 

[CWL]

One of the more interesting threads in a long time.

How about a test with pass-around where cotdt takes 2 knives/blades, re-hardens one of them and arranges a pass-around for everyone to test and post comparisons?

Maybe people in the pass-around can pony-up $5 each (a trivial amount), to help pay for the cost of the knives. After the pass-around finishes, we conduct a drawing for one to keep the knives.

Sound interesting?

 

[Gator97]

Actually that's a good idea if someone will handle the fund collecting shipping thingy.
I'll go through my stuff, see if I can donate something for testing...

 

[cotdt]

One of the more interesting threads in a long time.

How about a test with pass-around where cotdt takes 2 knives/blades, re-hardens one of them and arranges a pass-around for everyone to test and post comparisons?

Maybe people in the pass-around can pony-up $5 each (a trivial amount), to help pay for the cost of the knives. After the pass-around finishes, we conduct a drawing for one to keep the knives.

Sound interesting?

Sounds awesome. I'm in. The people who could correctly identify what is Knife A and B should get special recognition, too. What steel would people be interested in comparing before-and-after? I was thinking of using a Kershaw 13C26 but then the Kershaw fans on this forum would take it as an insult and give me flames.

COTDT,

I would also suggest that after your reheat treat, that both the treated and untreated knives be sent to one of the members here for sharpenning (my dime) so that we are comparing apples to apples. We could also circulate the knives for blind testing to a few members, who would post reviews.

Watcha think?

Chris

Great ideaChris! I'm thinking a passaround like CWL mentioned. Although I can do the sharpening part myself, I can set precise angles so that they match, and finish on 0.1 micron diamond paste. Most people here can easily refresh the edge if they decide to take part in the passaround.

cotdt....do u have any experience boosting the power of vg-10?.....ryan

I've never done VG-10, but I have some kitchen knives in VG-10 at 62 rc. I can follow the same formula. The reason they added Cobalt to VG-10 is precisely so that it can get harder than other steels in its class, if the manufacterer so chooses, as the steel was designed specifically for Japanese cutlery.

 

[Gator97]

VG-10 at 62HRC can be tricky I've seen several different sources stating 61HRC is a max for VG-10.
On the other hand I have Tojiro Flash series kitchen knives, both are VG-10 62HRC and I have never had any chipping problems with either one, but that's strictly in the kitchen and I do use them for designated purpose (santoku and paring knives), no hard materials there. However, quite a few people complain that Tojiros are overhardened.
So, I'd research or experiment on that topic...

 

[cotdt]

VG-10 at 62HRC can be tricky I've seen several different sources stating 61HRC is a max for VG-10.
On the other hand I have Tojiro Flash series kitchen knives, both are VG-10 62HRC and I have never had any chipping problems with either one, but that's strictly in the kitchen and I do use them for designated purpose (santoku and paring knives), no hard materials there. However, quite a few people complain that Tojiros are overhardened.
So, I'd research or experiment on that topic...

Yeah I got those Tojiros too after reading your review =) They are great, I love them. :thumbup:

The VG-10 held up in kitchen use. I'd bet that they are not very tough, like you say. My main issue is avoiding chipping. Maybe 61 rc is more suitable, would depend on usage patterns I guess.

 

[Phil Elmore]

What makes you so authoritative? Materials engineering training? Degree in metallurgy?

Does the original poster possess a degree in metallurgy or training in materials engineering?

 

[jimmyh]

I was thinking of using a Kershaw 13C26 but then the Kershaw fans on this forum would take it as an insult and give me flames

That would keep you from reheat treating my leek would it? You mentioned that you got your AEB-L (that's the same as 13c26, isn't it?) straight razor up to 62, but is that the highest you'd take it?

 

[theonew]

Does the original poster possess a degree in metallurgy or training in materials engineering?

Phil, come on man, enough, the last thing this thread needs is you're socratic trolling. Seriously if you're not interested in the topic just don't click on this thread. Don't start a petty argument that will just require moderator intervention, it's really annoying :grumpy:

 

[cotdt]

This is a great thread and Cotdt is doing a very good thing.
He is trying to let steel go for it's best performance.
I can see his point, as this is my reason why I began to make knives by myself.
I, too wanted steel to perform as good as it can go.

Thanks for the kind words. I've learned a lot from you on the other forums.

That would keep you from reheat treating my leek would it? You mentioned that you got your AEB-L (that's the same as 13c26, isn't it?) straight razor up to 62, but is that the highest you'd take it?

Haha yeah I could still do your Kershaw, the steel can go up to 63 rc. Not sure what to pick for the comparison blades. It would depend on what steel people would like to see. Kershaw moved onto 14C28N now so I don't think their fans would be offended if we end up picking 13C26.

There is nothing an individual can do to the heat treatment of a purchasezd blade except ruin it. This seems like a bizarre idea to me -- an unworkable solution desperately searching for a nonexistent problem to solve.

Good one, Phil

 

[Phil Elmore]

Phil, come on man, enough, the last thing this thread needs is you're socratic trolling. Seriously if you're not interested in the topic just don't click on this thread. Don't start a petty argument that will just require moderator intervention, it's really annoying :grumpy:

So any questioning of the basic concept is "sarcastic trolling?" There can be no legitimate questioning of the advisability of mucking about with the heat treatment of a perfectly functional knife?

I'll say it again -- this seems like a very bad idea to me, and anyone who avails themselves of this free service is going to get exactly what they paid for.

 

[Lucky Bob]

Does the original poster possess a degree in metallurgy or training in materials engineering?

My impression from previous threads was that he was in fact a practicing engineer. Even if that were not the case, extraordinary claims (ie that the heat treating guidelines published by the companies that develop and manufacture the steels will not yield their stated results, if they are followed properly, which, by the way, isn't all THAT hard for someone with decent home shop) require extraordinary evidence, of which you have provided none.

And I just gave in to the trolling, so if the mods desire, delete this and my earlier post.

 

[theonew]

So any questioning of the basic concept is "sarcastic trolling?" There can be no legitimate questioning of the advisability of mucking about with the heat treatment of a perfectly functional knife?

I'll say it again -- this seems like a very bad idea to me, and anyone who avails themselves of this free service is going to get exactly what they paid for.

Of course there can be questioning but apparently you haven't read through this thread or you would have noticed that there has been a lot of discussion about the process, benefits, dangers and technical details. So for you to just jump in and say 'you will just ruin a knife', 'this is a bad idea', without anything else to add to the discussion is pointless and trolling.

I meant "socratic trolling", one of your specialties :grumpy:

 

[Phil Elmore]

The basic flaw in your assumptions is that it is "trolling" to question the need or the advisability of this "free service." Nobody is claiming that the heat treatments offered by manufacturers are perfect. I simply can't see something like this provided for free by a private individual doing anything but ruining what was a perfectly good knife.

People are free to do any dumb thing they want with their knives, up to and including strapping on hockey masks and videotaping themselves stabbing cinder blocks and hammering the things to pieces -- but just because nobody's stopping you from doing it doesn't mean somebody shouldn't stick up their hand and say, "Hey, that... doesn't seem like a very good idea."

I don't care if the original poster is a traveling ninja rocket scientist with a degree in engineering from Miskatonic University -- this is still a really bad idea.

 

[theonew]

And I just gave in to the trolling

So did I

 

[Murphyslaw]

COTDT,

I'm still in. Nothing ventured, nothing gained....especially for those who strive for something better than average.

Chris

 

[Kiah]

I have no idea what the steel is they use. I'd guess it would be one of the Sandvik steels, but your guess is as good as mine as to what it really is. Someone should make an M2 steel SAK Cadet.

Quote from SOSAK in regards to INOX credited to Victorinox:

For both blades we use chrome molydenum stainless steel with 0.52% carbon, 15% chromium, 0.5% molydenum, 0.45% manganese and 0.6% silicium. After a sophisticated hardening process at 1040°C and an annealing temperature of 160°C the blades achieve a hardness of RC 56.

 

[sodak]

And you're saying that you've discovered something that they haven't? Something that all these company's metallurgists, who have been in this business for years, haven't figured out for themselves?

Actually, yes, I have. I know exactly what hardness range I want for specific knives in my collection. I've been playing with this for years, and from information I've gleaned from bladeforums as well as independent research and hands on practice, I know what I want. These companies know what will sell to the general public. Big difference. My needs are specialized, and tailored for what I'm looking for. None of these companies can know that, nor would it be economical to sell me a "one off". I don't expect it, so I therefore deal with it after I get the knife.

I don't understand this thread. There is nothing an individual can do to the heat treatment of a purchasezd blade except ruin it. This seems like a bizarre idea to me -- an unworkable solution desperately searching for a nonexistent problem to solve.

I've had knives re-heat treated to optimize edge retention on some of the smaller ones. I had a knife in S30V re-heat treated from 57 HRC to 60.5 HRC. The difference in edge holding while cutting abrasive materials was night and day.

In order to refute a generalization, only one counter example is needed. I just provided that, you are wrong.

 

[Phil Elmore]

In order to refute a generalization, only one counter example is needed. I just provided that, you are wrong.

You're right because... you say so? That does not strike you as just the tiniest bit solipsistic?

Far be it from me to criticize the one percent of the one percent of self-proclaimed super-users out there, but this sounds to me like an unrealistic level of perceived performance gains -- like building a rifle so accurate that no human being can wield it steadily enough to get that marginal performance increase from it.

Let's stipulate that such gains are theoretically possible. Sending a bunch of knives off to somebody to be "rehardened" for free still sounds like ruining those knives for no good reason, to me.