The "Ask Nathan a question" thread

[Nathan the Machinist]

I got a question-
Nathan, would you be so kind as to walk us(me) through the heat treatment process for a thick and large knife, (looks to some like a khukuri) of A2 please?

Preheat your oven 100 hotter than your austenitizing temperature

Wrap your blade in stainless foil. Double fold the seams and roll them. Place them where they won't interfere with the plate quench

Make a heat shroud out of foil to help reflect IR from the coils.

Once your oven is at temp for an hour, turn it off and put your work in. Place the heat shroud over the work.

Close the door and turn the oven on at your austenitizing temperature. If you've timed it right it will be pretty close so the exposed coils aren't on a long time burning your shit. Don't worry if you're a little over, the blade takes a few minutes to get up to temp.

Soak the correct amount of time for your application

Turn the oven off. Pull from the oven and quench between two metal plates to pull the heat out quickly. Ideally you want it under 100F in about a minute. This prevents the carbon from leaking back out of solution on the way down reducing certain carbides and maximizing strain energy to reduce RA. Don't worry about pearlite in A2 at this point. Any structures of that nature won't be formed here, it will be from decomposing retained austenite remaining when going into temper.

Once under 100 cut open the foil, hang it above the liquid nitrogen in a large dewer for enough time to get under -300F (an hour works). You can use dry ice in a pinch, you'll get most of the benefits at -100F

pull from cryo and warm until the frost starts to thaw. Clamp it straight and put it into temper. Temper two times (min) for an hour.

^ This is good basic HT for A2

Off the top of my head I'd guess for this application I might soak at 1725 for 30-40 minutes and my tempers might be 475 for a target hardness of around 58. You'll want to double check those numbers.


If you're just doing design development work you can skip a lot of that. Just get it hard and don't worry about a perfect HT.

 

[Lorien]

alright, got it!
Thanks!

 

[Brian77]

Nathan, in sticking to the topic regarding your use of synthetics, perhaps you can shed some light on this... if you were using a given material, perhaps one of the Norplex products, and you were acquiring it oversized and then machining it to your specifications, and assuming the standard deviation was somewhere within .02mm with a regulated trajectory of approximately half of its resonant frequency, would you expect that it’s covalent bond would allow for consistent dynamic tension?

Asking for a friend.

That’s the key to good bullshit, amiright?

If you're hell bent on achieving linear elastomeric coupling utilizing covalent bonds rather than the consistent spring rates of non-Newtonian (Brownian) metallic bonds I'd suggest you look into the newer carbon carbon composites. While conductive, it is still technically an organic synthetic. I guess it depends on your application. Is this your penis enlargement device? I'm not sure why you don't just keep using the garage door spring.

These should be put in a sticky. For Hall of Fame Nathan forum quotes. I chocked on my breakfast. The comedy team here is amazing!

 

[SharpPancake]

On a scale from 1 to 10 (10 is K18), how awesome is going to be Utility Fighter 2?

 

[Comprehensivist]

On a scale from 1 to 10 (10 is K18), how awesome is going to be Utility Fighter 2?

I don’t think Nathan releases anything that doesn’t score 9.9999% using that scale. Even then, he probably wakes up in a cold sweat in the middle of the night thinking about how to improve that last .0001%.

The Utility Fighter amazes me every time I pick it up. It is so well balanced, nimble, and maneuverable feeling. I can’t imagine the UF2 being any less so.

Phil

 

[SwarthyGnome]

Hello Nathan. I am quite excited to receive the weaponized K18. My question is regarding the profile of the blade: is the profile much different than a typical K18? Could you take a picture with the weaponized in front of typical K18?
My concern is I will need a sheath and the easiest potential here is an Azwelke.
Thank you.

 

[Icky Thump]

I don’t think Nathan releases anything that doesn’t score 9.9999% using that scale. Even then, he probably wakes up in a cold sweat in the middle of the night thinking about how to improve that last .0001%.

The Utility Fighter amazes me every time I pick it up. It is so well balanced, nimble, and maneuverable feeling. I can’t imagine the UF2 being any less so.

Phil

100%

UF probably my favorite. It really is awesome. Very much looking forward to the UF2, the Micro EDC and the DEK3..

So much to look forward to, really. I heard axe, integral..and another sword? Good stuff coming, for sure.

 

[Nathan the Machinist]

Hello Nathan. I am quite excited to receive the weaponized K18. My question is regarding the profile of the blade: is the profile much different than a typical K18? Could you take a picture with the weaponized in front of typical K18?
My concern is I will need a sheath and the easiest potential here is an Azwelke.
Thank you.

I would think a standard sheath would work.

I will take a picture on Monday for you.

If you would like, I could send this directly to a sheath maker for you.

 

[Grenock]

Hello Nathan. I am quite excited to receive the weaponized K18. My question is regarding the profile of the blade: is the profile much different than a typical K18? Could you take a picture with the weaponized in front of typical K18?
My concern is I will need a sheath and the easiest potential here is an Azwelke.
Thank you.

Me love kydex long time, BUT, that mf’er deserves leather. Chad, Bill, Paul or that narrow assed Canadian should be putting skin on this one.

 

[schmittie]

Apologies, I can’t figure this out. What’s a “hard thin” field knife? I know what a field knife is and I think it’s in 3/16” stock from what I read on the website. Is “hard thin” just a different heat treat and thinner stock?

 

[SharpPancake]

Apologies, I can’t figure this out. What’s a “hard thin” field knife? I know what a field knife is and I think it’s in 3/16” stock from what I read on the website. Is “hard thin” just a different heat treat and thinner stock?

No, stock thickness is the same, but the grind is more acute, thinner behind the edge as normal FK2.
And it's a plate martensite, harder, but not as ductile as Delta 3V. If you are cutting a lot of soft abrasive materials, it's a good choice. If not, go for normal FK2

 

[schmittie]

No, stock thickness is the same, but the grind is more acute, thinner behind the edge as normal FK2.
And it's a plate martensite, harder, but not as ductile as Delta 3V. If you are cutting a lot of soft abrasive materials, it's a good choice. If not, go for normal FK2

Thanks for the reply.

And that does it for me. I’m out. There is zero chance I will ever carry a 3/16” stock knife.

 

[SharpPancake]

schmittie you would be surprised how well FK2 could cut. I have standard variant, and the hard-thin should be even better.
From meal prep to batonning, you will not have an issue.
If you want a good cutter, DEK1 is a solid choice.

 

[SwarthyGnome]

I would think a standard sheath would work.

I will take a picture on Monday for you.

If you would like, I could send this directly to a sheath maker for you.

Hello Nathan.

Will you be able to post a picture of the typical K18 and the weaponized K18 to compare?
I asked Jo to mail it to Mr. Welke for a sheath, per your offer.
Thank you.

 

[Nathan the Machinist]

Hello Nathan.

Will you be able to post a picture of the typical K18 and the weaponized K18 to compare?
I asked Jo to mail it to Mr. Welke for a sheath, per your offer.
Thank you.

 

[schmittie]

Thanks for the reply.

And that does it for me. I’m out. There is zero chance I will ever carry a 3/16” stock knife.

Well darn it. I watched a few of Nathan the Machinist videos on YouTube on the field knife and now I’m conflicted.

 

[Lorien]

that was a sweet self own

 

[000Robert]

Well darn it. I watched a few of Nathan the Machinist videos on YouTube on the field knife and now I’m conflicted.

Here you go. Just in case you didn't find it yet.

 

[The Amazing Virginian]

Thanks for the reply.

And that does it for me. I’m out. There is zero chance I will ever carry a 3/16” stock knife.

Not thin enough? Not thick enough? Not metric enough?

 

[schmittie]

Not thin enough? Not thick enough? Not metric enough?

Personally, I like thin and light in a knife, especially when dealing with many of the super steels since they can do it just fine. Years ago I sold off everything 5/32” and up. Now 1/8” seems overkill.

Typically, with thin geometry you get a great cutter, which is all I’m after. But then theres Nathan’s video showing the performance of his 3/16....