Review: Terrain 365 STS-AT

Why Terravantium might be the best companion for your next waterborne adventure.

Review: Terrain 365 STS-AT

Imagine a knife that’s totally rustproof, no matter what… because there’s no steel in it. It’s also non-magnetic so it won’t disturb a compass on your next adventure. And last but not least it can ‘sharpen itself’ with use… sounds like magic?

Well, not really as it actually does exist and its name is: Terrain 365, model STS-AT with a Terravantium blade. And here’s my almost-two-season-long experience with it.

Stainless steel… it’s not rustproof, it just stains less. So if you want a knife, that is 100% rustproof in any conditions – simply forget about steel and take a different route. And it’s not a totally new concept – in the late 80’s David Boye made his first sailor’s knives out of a dendritic cast Cobalt alloy. It was revolutionary, but not perfect yet due to the technological constrains.

This material was further explored and enhanced by makers like Rob Simonich (Talonite) and Tom Mayo (Stellite 6K) in the early 2000’s. And recently Patrick Ma teamed up with Michael Vagnino to found the Terrain 365 knife company and they built it around the newest version of this blade material – Terravantium – the latest and greatest variant of Cobalt-based alloys. And it really works.

Terravantium is essentially a perfected Stellite, which can take a keen edge and ‘holds it’ virtually forever… or at least as long as you don’t hit something really hard, like a piece of brick, stone or nail in a board you whittle.

I won’t dive deep into modern metallurgy here (you can easily Google it) so let me give you a simplified version of how it works. Imagine a network of tough and sharp carbide crystals in a cobalt matrix. That carbide structure is held in place by the softer cobalt and together it creates a composite material with micro-serrated edge of micro-carbides, which cuts like crazy.

But the coolest property is yet to come: when the carbides structure on the edge starts to get dull during use (remember, we’re talking micro structures here) the softer Cobalt wears off at the very edge and exposes new and extremely sharp carbides, which makes the cutting edge aggressive and effective again.

As I said this kind of Cobalt-based alloys are not new, being used these days not just in knives bust also in industrial saws, drills, turning tools for lathes etc. so this concept surely works. And now, with new technologies, it doesn’t require additional rolling or forging, which is absolutely key to keep the natural carbide structure in the best possible shape. This makes Terravantium even stronger and more wear resistant compared to older variants.

OK, so where is the catch? Well, first of all that material is really, REALLY expensive to make and to machine, so it increases the price-tag significantly. But despite being extremely wear resistant thanks to the carbide-crystal edge, it’s not as tough on impact as modern tool steels.

So when you expect chopping or prying with your knife, or cutting stuff that can put your knife in contact with hard materials like ceramic, bricks etc. then Cobalt based alloys shouldn’t be your first choice.

So it might not be the ideal material for a tactical knife or a big chopper, but it really shines as an EDC folder used for daily cutting duties, outdoor stuff, in a camp kitchen, and during fishing or marine use. It won’t rust, cuts aggressively and stays sharp for long.

Design-wise the Terrain 365 STS-AT is based on the timeless Chute pattern and just adapted to a folding format. It’s sized just right for easy daily carry with 3.5 inch blade, an overall thin profile and internal cut-outs for weight reduction.

With a total weight of 4.2 oz it’s light enough for everyday carry but still has a solid feel to it, which I personally like a lot in an outdoor knife.

A double guard and pronounced clip-point blade defines the Chute style. Originally developed by world-renowned knifemaker Bob Loveless for a customer who was a CIA operator, wanting a knife for both covert spec-ops use and overall utility in any environment.

“Chute” comes from parachute of course, and since the 70’s such knives have become popular with airborne troops and special forces. So it’s definitely a time-proven design.

The swedge on the STS-AT is not sharpened (to comply with knife laws in most parts of the world) but still 3/4th of it hides between the handle slabs when the knife is closed, so could be easily sharpened if required. Oh, and it’s made in the good old USA.

The titanium handle is slim, but not too slim. Thanks to the lateral grooves it has no tendency to slip out of hand. It’s such an aesthetically clean design, with a satin-finished Titanium pivot being the only visible accent on the front side of the monolithic-looking handle slab.

The backside has just one extra handle screw on it, and a pocket clip of course. It rides great in the front pocket thanks to the 3D machined Titanium clip. Also, it doesn’t kill jeans as some more aggressive handle textures do. The titanium backspacer, with raised jimping panel (and built-in post for a lanyard attachment), is hidden between the handle slabs. All that makes the STS-AT such a clean looking knife.

Now let’s discuss the action. The ball bearings make it smooth, and the geometry makes if fast. I mean the geometry between the pivot, detent and thumbstud (and all other mechanical details), which was designed so perfectly.

The STS-AT is easily in my top-3 of most fidgety non-flipper knives I’ve ever handled. The blade literally flies open with a moderate push on a thumbstud. The STS-AT detent sits just in the right spot, which makes the knife both safe to carry and smooth to open.

The ambidextrous thumbstud is also big enough to be used with gloves, opening equally as easy with either hands, and the glow-in-the-dark insert helps to locate the knife in darkness. However, the pocket clip is not reversible for lefties, which can be an issue for some.

The framelock is rock solid and non-sticky. It’s clear that both guys, Patrick Ma and Michael Vagnino, are not newcomers to this business. Actually both have many decades of experience under their belts. So all that shouldn’t be a surprise… yet the knife mechanics are so good that it’s hard not to rave about it.

Terravantium cuts very aggresively. It doesn’t feel as sharp as steel when touched, but it bites hard and deep with even the slightest slicing motion. Cutting food, cleaning fish, preparing a BBQ – I did all that with my STS, no issue, it worked just like any other steel blade… the only difference was edge holding, which is really amazing compared to most steels.

I also prepared handful of feathersticks with it, scraped fatwood with the edge at 90 deg – all that with zero edge issues. This was quite surprising, especially the scraping, where I even expected some micro-chipping, but… nothing happened.

Rope cutting is something that the Terravantium excels at. Also general cutting like sharpening tarp pegs, cutting cardboard etc. is pure joy with the STS-AT knife.

I could work on and on with that Terravantium blade. And when it finally needed some touch-up on a sharpener… that must have been the easiest and fastest sharpening process ever. Diamond hone (like the Fallkniven DC4) is probably the best tool to get that blade back to aggressive sharpness again. Easy job.

All in all, after two seasons of use I simply cleaned it, sharpened slightly, and it looked great again, almost like a new knife.

I took it to the mountains, on a boat, to my local woodland area etc. Yes, I know that this Cobalt-based composite material have some limitations, but as long as you’re aware of them – it’d make a very special cutting tool for the sensible outdoorsman.

And if you live in a hot and humid area, like on the coast or near lakes, or you plan to spend an extended period of time in such an environment – the Terravantium blade of the STS-AT might be your best friend for your next adventure.

It’s a really good, unique knife and it will stay in my collection for a long time. I’m planning some sailing adventures for the summer in 2021… guess what starts my edged tools shortlist on No.1? Yep, the Terrain 365 folder. Terravantium blade for the win!

By Piotr Ma

Senior Contributor & Edge Specialist, more posts.