Spyderco Endura 4 ZDP-189
Folding Knife Review

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Spyderco Endura 4 ZDP-189 steel

Spyderco Endura 4 was my second Spyderco folder ever, and the very first Spyderco folding knife I have actually liked and started carrying it :) It's been more than 15 years since I have started collecting knives, and I have known about Spydercos all those years. Obviously so, because Spyderco is one of the leading knife makers in the US and the world, and one of the most recognizable knives by their unique design. Speaking of which, the unique design of Spydercos, was the main reason I have never bought a Spyderco knife before. I'm definitely not alone in that regard, for majority of the people, Spydercos are love or hate affair. Some people swear by them, have almost every model even produced, and others can't stand their looks. It's rather rare to see middle ground though :) Anyway, that's not to say I hate Spydercos, sadly, I just never liked any of them enough to buy them. Sadly because, for a knife collector, Spyderco is one of the best knife companies. They constantly experiment with new alloys, have numerous collaborations with some of the most famous and respected custom knife makers, their heat treatment of any steel is pretty much as good as it can get for a production knife. There's nothing more you could ask from a knife company, except for the design you'd like... Alas, I've tried more than one to like them, but it never happened. After long deliberations, I did get the Spyderco Military Fluted Titanium special edition folder, which is a nicely made knife in itself, but I didn't really like it, still sitting in the drawer, never made to my EDC rotation list, which is why I am reviewing Endura 4 first, since I liked Endura 4 quite bit, and reviewing stuff that I like I a lot more interesting :)


 - Spyderco Endura 4 as the name suggests, is the 4th version of the Endura model. As far as I understand, the first Endura was introduced back in 1990. Plus, there are variations within each version, handle materials, blade grinds, various steels, etc. This particular model is C10KB, using Hitachi ZDP-189 steel for the blade material. Actually, Endura 4 C10KB model according to Spyderco website uses Takefu VG-10 steel, which makes ZDP-189 steel model a limited edition. Well, being an expensive and difficult to work with alloy, it is being used in high end custom knives. Overall, Endura is a lightweight, medium size, sturdy folding knife. As far as fit and finish go, the knife was pretty much flawless. No wobble anywhere, parts fit perfectly, lock back bar is nicely polished. There is no blade play neither vertical nor horizontal. Blade finish is very smooth, no scratches or swirl marks. In short, very well made knife, I had no complaints after very careful examination. The only thing that was not really matching overall quality of the knife was the edge. It was very rough, and bevels were not very even. Later, when I was sharpening the knife, I've started with 220 grit stone, and even that smoothed the bevel, so obviously the knife was sharpened with something rougher than that. Although, to be fair, it was pretty sharp. Just for my taste, or in my opinion, ZDP-189 steel is better of with high polish edge, and in general, even for coarse grained steels finishing the edge with sub 220 grit is too much, well, I mean too low, or too rough. On the other hand, factory edges are a hit and miss, and sadly most of the times they are a miss. To me at lest. Most of the non knife folk don't really pay too much attention to the edge quality, so knife makers don't stress them out on that subject either. However, a folding knife with a price tag almost 100$ is hardly something targeted at an average, non knife buyer either. Well, ZDP-189 steel isn't average steel either, it is still a high end, exotic steel. So, overall, it is a very good knife and whatever the edge sharpening shortcomings were, it doesn't really matter, I say pretty much in all reviews. No edge will last forever, so eventually it has to be done anyway, multiple times ;) It wouldn't hurt to have a better edge, but at that price, ZDP-189 folder, I'd buy with no edge too. The only thing I am not very happy about is the lockback type lock on this knife. I rate it higher than the liner lock, but having more modern type lock would've been nicer. As far as lockback specific type goes, it's a frontlock. In other words, lock release is in the front part of the handle. Ideally axis lock, but that's Benchmade patent for now. On the other hand, Spyderco themselves invented several different lock types, including ball bearing lock, which operates similar to axis lock, apparently not as smooth though. Still, it would've been better than the lockback, which requires two hands to properly operate. Actually, I stand corrected on that one. Shortly after publishing this review, I was contacted by Spyderco fan, unfortunately, he didn't provide return email, so I couldn't even say thank you. Anyway, turns out, Spyderco themselves, published one hand opening/closing instructions on their site, follow the link for the illustrated, detailed instructions, I'll skip the description here. As for me, I'm still using two hands, despite Spyderco's instructions, which also urges to use caution when utilizing one handed opening/closing method, I find it rather awkward, and IMHO there is no need to do that, unless the circumstances force you to do so.


 - Endura 4 has a full flat ground, 96mm (3¾") long blade. At its widest the blade measures 31mm. Thickness, around the trademark Spyderco hole, or also known as Spydie hole, is ~3mm. That's pretty common thickness for the folder blades of that size. As far as the blade geometry goes, basically, it's a triangle, with slightly curved edge side, still very distinct Spyderco design, completed with the opening hole mentioned above. Overall, the blade geometry is quite utilitarian. There is a thumb ramp behind the opening hole, the blade has a bump in there, formed to provide enough space for the opener, and back side of that forms quite convenient ridge as a thumbramp. Notches on the ramp are just right, not too aggressive to bite into your finger, and yet secure enough to prevent slippage. The tip is narrow, and suited for delicate work, and for the very same reason, it is not suited for prying. Actually, very few knives can handle prying, and I think no folder really can do it, it's an abuse and you're asking for trouble if you do that. The large hole in the blade is another reason why one should refrain from prying with Spyderco folders. Like I said, the blade is pretty much triangular, but it still has some belly, although not much to speak of. At any rate, for slicing and push cutting it performs pretty good. Obviously, bigger belly would do better for slicing, but it is fine as it is, for a folding knife. Out of the box sharpness was ok, but as I said above, grind was rough, and uneven closer to ricasso. I've spend about an hour sharpening the knife to my liking, and now it has ~100K grit mirror polished edge. ZDP-189 steel does work well with polished edges, and so far I am very happy with its performance. Initial edge was somewhere between around 20° per side. I'd guesstimate 18°-20°. Guesstimate, because measuring the edge with 1° accuracy isn't that simple. I've sharpened the knife to 15° per side edge, and that widened the bevel, visibly. Factory edge was more of a V grind than a convex, and after sharpening freehand, it did end up with nice convex edge.

Based on the advertised specification of the knife, ZDP-189 steel is hardened to 63-64HRC. In time, I'll thin it down to ~12° per side. I am familiar with this alloy, and I know it can angle that thin, in a folding knife that I will use for light cutting chores. As far as I know, Hitachi is very protective of this steel, and all the heat treatment is either done in Japan, or at least according to their requirements, some sources disagree on that. Anyway, most of the knives I've had or heard of made out of ZDP-189 steel were around 64HRC-67HRC. I do believe Hitachi might actually have some influence on that, because there are lots of other steels out there capable of very high hardness, starting with good old M2 tool steel, which goes up to 66HRC and with more modern CPM S110V steel, which can easily handle 65HRC, yet those alloys never get hardened to their full potential in factory knives. ZDP-189 somehow gets special treatment ;) In short, I don't know what goes on behind the curtain, hard to imagine Hitachi chasing every knife making company with their requirements and inspections, but it can be done in a simpler way too, by requiring heat treatment in Hitachi affiliated or controlled factory. Oh well, enough of that, it's a very good steel, and the fact that it gets good heat treatment makes things close to ideal.


Last updated - 05/19/19