Photos Vintage Artus Flex knife

Discussion in 'Knife Reviews & Testing' started by kwackster, Oct 12, 2019.

  1. kwackster

    kwackster

    Dec 23, 2005
    Recently i obtained several unused Artus Flex knives, and i'm currently experimenting a bit with one of them.
    All knives came complete with original box, leaflet, spare belt loops & mini-tool (to exchange them)
    The Rockwell hardness sticker is still on the blade.

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    Specs:

    Overall length: 9.69 inches (24,6 cm)
    Blade length: 5.0 inches (12,7 cm)
    Blade thickness: 0.96 mm (!)
    Handle materials: steel guard & molded rubber grip
    Sheath: glass filled nylon with spring steel insert
    Weight (knife only): 119,3 grams
    Weight (knife + sheath): 260 grams

    This background info on these German made Artus Flex knives was translated from a German knife forum.
    According to the poster the Artus company designed the original version of the Flex knife for use with certain government agencies (GSG9, Bundesgrenzschutz, and police) around 1988, and at that time it was solely meant as a tactical knife.
    Apparently the idea was to make a fixed blade that would be rigid enough to both stab & cut well, yet which would also be flexible enough to be carried horizontally on a belt in a specially designed sheath which holds both handle & blade in an arc shape to better follow the contours of the human waist.
    Once drawn the knife returns to dead straight again and is ready for use.
    The poster said that he owned an early all-black Flex knife (but did not show any pictures), which he once received as a birthday present from his wife, who at the time worked at the Artus company in the German city of Lüdenscheid.
    He also stated that at the time the Artus company designed & manufactured many more items for said agencies, like tactical vests, helmets, etc.

    Some time before introduction of the Flex knife to said agencies however it all fell apart.
    Apparently Artus' owner (or it's chief executive, the poster wasn't sure) was caught bribing a certain government official for his assistence in selling the Flex knives in larger quantities to the agencies mentioned, but somehow other authorities found out and the owner was arrested.
    While still in custody the man commited suicide by hanging himself, and all of this seemed to have been quite a big scandal in the German press at the time.
    The affair also led to quite a crisis for the Artus company, and among other things it was then decided to try to sell the Flex knives on the open market to consumers in an effort to recoup at least some of their investments.
    A marketing campaign was launched, and the all-black tactical style aimed at military/police was thrown out to entice entirely different but possibly interesting markets like outdoor & sports, and the knives from then on were offered in various handle & sheath colors.
    In the end however the Flex knife never became the success story that the company envisioned, and the then considered high introductory price of ~300 Deutschmarks (currently ~221 Euro or ~248 US dollars) didn't help either.

    The knife itself and it's sheath system however were definitely well made items from quality materials.
    True, the designers seem to have gotten their inspiration for the overall appearance of the Flex knife from the classic Al Mar SERE fixed blade (to put it mildly), but from there the designers then created a radically different knife.

    Pictures i took from the pages in the brochure:

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    Last edited: Jun 26, 2020
  2. kwackster

    kwackster

    Dec 23, 2005
    The factory edge on this knife was a bit blunt due to one of the black plastic inserts in the sheath, which is made from some form of glass filled nylon.
    Not exactly a good choice for a part of the sheath that contacts the edge often.
    Will see if i can do something about that.

    With the sheath partly disassembled showing both black plastic inserts, as well as the one-piece flat stainless spring:

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  3. kwackster

    kwackster

    Dec 23, 2005
    I think i may have found a solution for the edge blunting from the black glass filled nylon insert.
    First step was to grind some material from the insert with only a coarse diamond file, thus also leaving a coarse surface.
    After cleaning/degreasing that surface with some isopropyl alcohol on a piece of microfiber cloth i applied 2 layers of waterproof PVA wood glue on the surface of the insert. (allowed each layer to dry overnight)
    PVA stands for polyvinyl acetate, which is the same or close to the same material that expensive Hi-Soft cutting boards are made from, and these are known to be very edge friendly on knives.
    When everything had thorougly dried I tested the new PVA surface by slicing it several times with a freshly sharpened cheap peeling knife (picture 4), and this did not noticeably seem to blunt it's apex.
    Next step will be to resharpen the edge of the Flex knife and see how things go from there.

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  4. oldmanwilly

    oldmanwilly Gold Member Gold Member

    344
    Mar 7, 2014
    That is certainly a unique design. Thank you for the write up, I would have never known such a knife existed without it.

    Quick question: is there any info on what kind of steel they used and how they tempered it so that it would always return to center?
     
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  5. kwackster

    kwackster

    Dec 23, 2005
    According to the brochure the blade is made from a saltwater proof stainless steel with a hardness between 57-59 HRC, and capable of a highly durable cutting edge.
    Now i have exactly zero proof as it isn't mentioned anywhere specifically, but based on this info plus sharpening/deburring/polishing the edge on one of the Flex knives my educated guess would be that the steel might be Becut, as this would fit the properties described almost perfectly.
    Wet-grinding completely new bevels on the Tormek SB-250 stone (black silicon carbide) is comparatively slow, and both deburring/polishing with high quality diamond compounds tells me that there are quite a lot of wear-resistant carbides in the steel.
     
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  6. DocJD

    DocJD

    Jan 29, 2016
    :) Thanks for the review !

    Interesting concept and one I'd never heard of before . :cool::thumbsup:
     
    David Mary likes this.
  7. kwackster

    kwackster

    Dec 23, 2005
    The factory edge on this Flex knife measured ~30 degrees inclusive and was reprofiled to ~22,5 degrees inclusive on the Tormek SB-250 Blackstone fitted with the homemade jig you can see in the last picture, then deburred on the Tormek leather wheel coated with 1.0 micron diamond paste.
    This provides for just a tiny bit of micro-convexity of the apex which strengthens it, and the resulting edge is now stable & reverse chesthair-whittling sharp.
    This was actually the third time i had to redo the sharpening, as the first two times the edge collapsed from a few firm slices into a polyethylene cutting board.
    My guess is that the factory edge may have been overheated during sharpening.

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  8. kwackster

    kwackster

    Dec 23, 2005
    Currently busy sharpening two other Flex knives on the Tormek; a second yellow one and a pink one.
    From top to bottom: the second yellow knife (with taped blade) which has just been sharpened on the Tormek to ~22,5 degrees inclusive and with the burr still attached to the edge, the pink knife (with taped blade) still with it's ~30 degrees inclusive blunt factory edge, and the first yellow knife.

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  9. kwackster

    kwackster

    Dec 23, 2005
    A few days ago i showed the Flex knives to a local pro-Chef who also likes to fish at sea (and serves the catch in his restaurant), and he seemed to like them quite a bit as possible filleting knives, praising their thin flexible blades, presumed saltwaterproof steel, very grippy artificial rubber handles with trustworthy guards, and probably good edge holding as well.
    Other possible uses that i can think of atm would be (camp-) kitchen use, and maybe even diving knives.
     
    David Mary likes this.
  10. kwackster

    kwackster

    Dec 23, 2005
    Each blade is just under a millimeter thick, and also quite flexible for such a relatively hard & wear resistant steel.
    Not my picture, but it gives an idea of both the blade thickness and the flexibility of these knives:

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    David Mary likes this.
  11. panella

    panella

    Sep 2, 2003
    Very cool find!

    As I own two Al Mar SERE Operators I can’t fault the blade design. As intended for military use, you have to wonder about the flexibility being a liability for stabbing e.g. through military clothing. Nevertheless,
    it’s an innovative approach. Thanks for the review and congrats for owning a rare piece of forgotten history.
     
    David Mary likes this.
  12. kwackster

    kwackster

    Dec 23, 2005
    @panella: my guess is that the blade would be stiff enough for stabbing, but i intend to do some non-destructive testing later on.
    I was thinking about several layers of denim on top of a stack of cardboard.
     
    David Mary likes this.
  13. kwackster

    kwackster

    Dec 23, 2005
    This is how the second yellow Flex knife came out:

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    Blade thickness: 1,0 mm
    Thickness behind the edge: 0,30 mm
    Edge angle: ~22,5 degrees inclusive
    Microbevel: ~30 degrees inclusive

    And the pink version:

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    Blade thickness: 0,98 mm
    Thickness behind the edge: 0,27 mm
    Edge angle: ~22,5 degrees inclusive
    Microbevel: ~30 degrees inclusive
     
    David Mary likes this.
  14. kwackster

    kwackster

    Dec 23, 2005
    This afternoon i carried the first yellow Flex knife on my belt, with the T-shirt tucked in and the fleece jacket covering the sheated knife, which concealed it completely.
    Even under just a loose hanging dark blue T-shirt there's not much printing.

    Impression so far is that the sheated knife wears very comfortably and i don't even notice it when tying my shoelaces, walking around, driving a car, or having a snack at a table.
    You could basically carry this knife all day and forget that it's there at all, and yet it's still very accessible.
    What also seems to work well (so far anyway) is the PVA glue mod i did inside the sheath, as the self-blunting effect on the edge is gone and it stays sharp.

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    David Mary likes this.
  15. panella

    panella

    Sep 2, 2003
    Very cool! I can see the tactical utility for concealment wearing the knife horizontally.
     
    David Mary likes this.
  16. kwackster

    kwackster

    Dec 23, 2005
    And because of the thin stainless blade & very grippy handle the Flex knife also does quite well as a tactical petty knife, :D
    Tonights dinner was a sauerkraut oven dish with bacon, sausage, onions, and garlic.


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    David Mary likes this.
  17. kwackster

    kwackster

    Dec 23, 2005
    Article about the Artus Flex knife in American Tactical Knives magazine.
    The picture can be clicked 2 x then enlarged further to read the text.

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  18. kwackster

    kwackster

    Dec 23, 2005
    All the knives now have the "anti-selfblunting mod" done, and have their edges carefully resharpened on the Tormek.
    I will probably keep 2 of these for my own collection, one is already on it's way to a US forum member, and the remaining 5 will also go up for sale.

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    David Mary likes this.
  19. kwackster

    kwackster

    Dec 23, 2005
    Personally i knew about the Flex knives only through an old German knife magazine, and i never even saw or handled one in real life before i bought these.
    So far and from actual hands-on experience i learned that the sheathed knife carries very comfortably as well as inconspicuously on a belt, and accessibility of the knife is also great (although not super fast)
    After a while i actually tend to forget that something is strapped to my belt, an aspect that could make it more likely that you have it on you when you need it.

    While the thin blade indeed has a certain amount of flexibility it has no distal taper and is also relatively wide, both of which lessen that flexibility quite a bit.
    The knife is definitely stiff enough to stab with, aided by the very secure steel guard & the grippy rubber handle.
    Regarding actual use i really like it for allround kitchen jobs, and it's definitely coming with me on our next camping trip.
    It also excels in cutting cardboard, and i use it quite a lot for that.
     
    Last edited: Nov 4, 2019
    David Mary and mycough like this.
  20. mycough

    mycough Basic Member Basic Member

    May 20, 2007
    What a great thread! I remember someone on jerzee devil had a handful of them to sell and had a picture of the flex aspect. Very cool of you to post this, another reason I love BladeForums.
    Thanks Kwackster, Really appreciated...

    Russ
     
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