knife review

Historical Background and Review of the German Mercator Knife (aka "Cat Knife")

The German Mercator knife is as simple as a locking knife can get. It has been around for over 140 years and has become an immortal classic. And it is still a great every-day utility knife at a reasonable price.

Here’s the link to a video that was filmed at the shop of Otter-Messer, Solingen. It shows the making of the Mercator knife:

20 replies on “Historical Background and Review of the German Mercator Knife (aka "Cat Knife")”

Sehr cooles Video. =)
Wusste ich so gar nicht. Interesse ist geweckt.
Kannst aber ruhig Videos auf deutsch machen.
Wäre ok für mich. Englisch geht auch..aber na ja.. 🙂

Excellent video, as always, Mr. Schmalhaus. I wonder when an English version of your excellent book would be available. I have purchased the Mercator because of a video of yours and, since then, I am very happy with this knife. In fact, that is the only EDC knife that I carry for food prep — peeling an orange with it is such a pleasure… And, as you say, its price was quite reasonable. Thank you for letting me know some of the history of such a dear to me blade.

I'm kind of surprised at the claim that the lock bar takes "serious pressure" to open. Mine seems pretty much in line with all the other lockback knives I own. It isn't going to accidentally open (good, considering the location of the lock bar, right under the palm, and protruding where it can easily be pressed), but it doesn't strike me as unusually hard to operate either. I also don't detect anything that I would call "blade play" on my example. There is a very, very slight movement, but it seems to be more due to the natural flexibility of the thin steel blade than any looseness in the pivot. The lockup is good and firm, with a crisp "snap" as the lock falls into place (as you can hear in the video). The ergonomics are okay, better than a douk-douk or higonokami_, and the looks are quite pleasing (I suspect the switchblade-like appearance has a lot to do with its alleged popularity with gang members and toughs in the 1950s and 60s, along with the cool-looking black cat on the handle). I'm glad you mentioned that the "bail" can block the blade, since I hadn't noticed that myself yet. What I _have noticed is that it makes a very effective blade safety lock, preventing the blade from accidentally opening in the pocket. I personally suspect that is at least partially the intention of the designer, both on this and the douk-douk . If they just wanted a place to fix a lanyard, they could have just punched a hole like the higonokami they didn't need this complex 'bail" riveted to the handle, which increases the part count and manufacturing complexity by a significant amount of the total.
Construction quality is good, especially for the price. The steel is okay, I think C75 carbon steel is what I read. It takes a sharp enough edge, but not as sharp as an Opinel (at least I can't do it by hand). The black cat logo is "upside down" by modern standards; it is designed to be read with the knife laying on its spine, while most modern knives are designed to be read while blade down. I'm quite happy with it, and I would carry one EDC gladly if I didn't have better knives available. I keep planning to try it, but I jhaven't got around to it yet (which isn't to say I haven't carried it around in my pocket). The black paint finish becomes lightly scuffed easily, none has chipped off yet, which is more than I can say for a higo. The paint seems rugged enough, and thick as well, so it should take some time to wear totally through. The black cat logo is pressed into the metal so it will survive even if the paint becomes damaged. Re-painting the logo or even the whole handle should be easy enough. Of course, being riveted means it is basically impossible to disassemble it for cleaning or working on it, which is too bad, but not at dealbreaker at all (I personally don't take my knives apart even when I could theoretically do so). I just worry a little every time I get the knife wet or dirty inside, because it's impossible to clean or dry it. All you can do is oil it and wait for it to dry).

Thanks for video…nice job!! I just bought a Black Cat and it's nice to know the history. Very unique knife!!

anyone know anything about an almost identical knife with a cat just like that but it says omor instead of the k55k and was made in japan?

Stefan, If I remember correctly their is one of these knives with a corkscrew and can opener and awl. Does that knife have a name or model number ?

Stefan, Speaking for myself, could you some day do a video on the GAK pattern 1 and 2. In the USA, you don't get much information, like why that design was chosen. I find the combination blade saw and can opener (I assume it will also open bottles) and screwdriver very unusual.

I came across your video while doing some research about the Mercator knife (I am considering to purchase one of its many variants). Great video by the way, I learned more from watching this than from all of the other sources combined! Just a small question: Which angle did you use on the Sharpmaker to sharpen it? 15 or 20 degrees? Thank you.

A great Solution as EDC – Tool . I love this part of German History and Story in his backround…! I mean its possible to hold this herritage when you use and collect one of this knives and explain this another people which interesting in Knives. Best Regards and take Care Stefan

After owning several Douk-Douks, I wanted another classic to carry. I prefer locking knives, and being in the states its ok to carry. Ordered off BladeHQ for $27, no beating that. Love the look of it, hope it performs just as well.

do you know anything about a fixed blade, stag handle, marking are a running puma with k55k on tang. k is backwards.

Fantastic explanation and history of this knife. When I was a child I remember huge fuss and the police searching the grounds of my primary school because a 'Black Cat Knife' was found lying near the football field and for weeks parents were talking about teenagers getting more dangerous and like American gangs, and anti-social activity. Punk rock music got the blame, of course. I was always wondering what exactly a Black Cat knife was, but assumed it was just slang, until I came across your superbly executed and interesting video here completely by random.

I have this knife it has no cat marking or k55k numbers but it is still a good knife..i believe it is carbon steel…what is the best way to preserve and look after this knife? Thanks for your suggestions

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