Benchmade 100SH2O River/Dive
Knife Review

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Benchmade 100SH2O River/Dive Knife

Like many other knives reviewed on my website, Benchmade 100SH20 river/dive was not my own. Friend asked help with picking a knife, for surfing. Given its properties, 100SH2O was pretty much ideal candidate for a surfer. Impervious to corrosion, small enough not to cause inconvenience when strapped to ankle, tip is rounded, which is important requirement for all underwater knives, plus it was made by well known knife company, so quality and durability were not the issue. The knife arrived to me, I've had it for some time, sharpened it and gave it to the owner. That's the short story how the knife ended up with me. Now about the knife itself.


- Benchmade 100SH2O is a small fixed blade knife. I guess it's safe to say - small, I can't see how 3.26" long blade can be considered big by any stretch of the imagination ;) The knife arrived packed in a traditional Benchmade box with the famous butterfly on it. Package included the sheath and the rubber straps for it. Initial examination showed no visible defects on the knife. Fit and finish were good. Nice satin finish blade made out of Myodo H1 stain resistant steel at 58-60HRC. No scratches or significant swirl marks on the blade. Handle slabs were well machined, smooth and fitted with the blade very well. At least I didn't find anything wrong with it. Also traditionally, the edge was quite rough, I'd guess around 800 grit or rougher finish. Approximately 40° inclusive angle. The knife is quite light, just 113g(3.8oz), given its size, that's obvious. Blade fits the sheath quite tight, and in addition to that, the sheath has a lock, which is easy to operate, but even though I've experimented to simulate accidental opening, I couldn't do it. In other words, chances that you will accidentally release the lock and then loose the knife are very low. Of course, I cannot state, that's impossible, but it has to be some really weird accident. Now, I haven't gone diving or fishing with it to test the knife in its designated environment, but granted that my buddy was surfing with that knife for a while and he still has it, knife retention in the sheath it good and the lock performs its function well.


- 100SH2O river knife features 82.80mm(3.26") long blade, whish is 3mm thick throughout most of the blade, narrowing down a little bit closer to the tip. The blade is 31mm wide at its widest, also narrowing down towards the tip. As far as the balde geometry goes, I'm having hard time classifying it, it's a drop point, but very strong drop, comes closer to sheep's foot style. Actually, come to think of it, it's quite similar to Japanese Santoku knife blade geometry. Anyway, whatever it is, it does have rounded tip, more or less so, and underwater, it is more important, since you definitely do not want to poke a hole in your or someone else's equipment.

As I mentioned above, initial edge was closer to 40° included. When I sharpened the knife, I've left it at the same angle. I figured, underwater knife, it's not gonna be used all that much for cutting, at least for its current owner. Besides, with all due respect to H1 steel, edge holding is not one of its best characteristics. Although, I do not mean its really bad either. I mean it's not on the levels of CPM 10V or ZDP-189.

H1 steel

- One of the most interesting detail or aspect of the knife is the steel used in it. H1 steel made by Japanese company - Myodo. By definition it's a low carbon steel, with just 0.15% C in it, however its Chromium content is high, 14-15% and it also has anywhere from 6% to 8% Nickel to boot. Both chromium and Nickel increase steel's stain resistance, and given very low Carbon content, the end result, in terms of stain resistance is pretty much absolute. As Sal Glesser stated We've done extensive testing with H-1 for the past year plus. We were disappointd that Benchmade beat us to the market with H-1, but I have to give them credit for doing their homework. The steel is a break through in corrosion resistance. It is another "nitrogen added" steel like CPM-S30V, X15Tn and Infi. It is a precipitation hardening steel. In "Q-Fog" testing, H-1 ranked with Cobalt based materials such as Talonite, Dendritic cobalt and stellite 6K. There was NO rust. Much better than even 440C. So, there you have it, the steel that wouldn't rust even in specifically designed environment. Q-Fog mentioned in the quote above actually is a Q-Fog Cyclic Corrosion Tester, special device that allows to simulate natural corrosion in the laboratory environment, produced by Q-Lab. H1 has its pros and cons. With stain resistance at the same level with Cobalt alloys, which are considered impervious to rust, its price is considerably lower compared to those Cobalt alloys, thus the knives are also cheaper. However, edge holding ability is lower compared to Dendritic Cobalt, but according to Sal Glesser, it's on par with AUS6 and AUS8 steels from Aichi. I've never used AUS6 steel knife yet, but AUS8 does ok for a budget general use knife, and works quite well for the knives designed for use in corrosive environments. In other words, dive, river, etc. Still, around saltwater and in highly humid environments, AUS8 steel is still susceptible to rust if neglected. H1 steel will survive much better, however the previous sentence shouldn't be taken as prompting knife neglect ok?


- The handle on the Benchmade 100SH2O is made out of good old G-10. Two slabs are attached to the tang using two hex screws. There are two oval plates embedded in the handle slabs, left side featuring Benchmade logo, and the right side stating H2O. The handle has very subtle texture to it, which is enough to provide secure grip, and at the same time it didn't cause irritation to my palms while I was test cutting cardboard and other items. There are four perpendicular grooves on the slabs, I would assume they serve the same function, to improve grip security. Their depth isn't significant enough to imply weight reduction or some other function. May be those are purely decorative, but still help with the grip. I've commented on G10 in a lot of other reviews, and don't really have too much to add here. It's a durable material, stands up well to lots of chemicals and elements. Impact and scratch resistance is also good. Tough stuff for hard use knives in short. Nothing fancy though.


- Overall, H1 steel at 58-60HRC is pretty easy to sharpen. Considering that I constantly deal with 64-67HRC steels, plus much more wear resistant than H1, it seemed very easy and sharpening was done in less than 30 minutes. The blade already has serrated part, so for the straight section I put nice mirror polished edge, going through several steps, starting with 1200 grit king synthetic waterstone, followed by 3K Blue aoto synthetic whetstone, then Naniwa Chosera 5000 grit whetstone, and finally Kitayama 8-12K synthetic waterstone. Then the usual stropping on the microabrasives, specifically 0.50µm and 0.25µm diamond crystal loaded strops, all that finished with stropping on the plain leather. One might say, it was not really necessary to do all that on the diving knife, but like I said, it was an easy work, I didn't have to spend even 5 minutes on each stone or abrasive, and it couldn't hurt anyway. Besides, it's a good practice too. After I've used/tested the knife for some time, the edge lost some of its sharpness and I touched up on .50µm and 0.25µm diamond loaded strops to restore its initial sharpness. That was it as far as sharpening was concerned.


- I didn't have to do any serious cutting with this knife. I already had pretty good understanding what to expect from it in terms of edge holding, and besides, its designated use didn't imply prolonged cutting sessions anyway. There was nothing to test in corrosion resistance department either, Sal Glesser's results are above. So, I focused mainly usability, grip security, sheath/carry system etc. One thing I wasn't so sure about was the grip comfort, it's a small knife and my palms are relatively large. As it turned out, my worries were not really justified. Performing various cutting tasks in my garage, including about 100" cardboard, two different types of rope, small wiring and few other small items, finished with wood whittling. Some of those tasks were not what I'd expect to perform underwater, e.g. wood whittling is not exactly underwater sport, but cutting a cord is one of those things a surfer might need to do with that knife. In all grips the knife was quite comfortable and secure. At any rate, I never had to struggle with the knife itself or change grips several times to feel comfortable. Even though the handle is smallish, it still managed to stay comfortable throughout the test session.

I am sure, if I had to cut few hours in a row, things would've turned out a little differently, but then again, the knife is not designed for that, it's more of an emergency tool and for that sort of work it performs very well. Very high rust resistance definitely adds to its value as a saltwater knife. Overall, the carry system is pretty good, and while I can't say you will not notice the knife/sheath on you, it's definitely not bulky or heavy to become a nuisance. I'd rather be swimming or diving with that knife on me than without it. Actually, swimming and diving aside, if I had to stay in high humidity area, like camping in a swampy place, (why the hell would I do that is a different question), but if I had to, this knife would be one of the top choices for a beater knife in there. And, finally, Benchmade does produce another type of diving knife - 110H2O, which is made from Bohler-Uddeholm N680 steel, also very high corrosion resistance, less than H1 though, but as per Benchmade, it has better edge holding than H1. Benchmade 111H2O is a folder, designed for the same purpose, although, personally I'd rather have a fixed blade venturing underwater, but then again, being honest I have to admit, I've never done scuba diving or surfing ;) So, consider all that when reading my speculations about what I'd do underwater.

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  • Blade - 82.80mm(3.26")
  • Thickness - 3.00mm
  • Width - 31.00mm
  • OAL - 190.50mm(7.5")
  • Steel - H1 steel at 58-60HRC
  • Handle - G-10
  • Weight - 113.40g(3.83oz)
  • Acquired - 09/2009 Price - 95.00$
  • Warranty - Limited Lifetime

Last updated - 05/19/19