OT: Convexing a kitchen knife... or not

Discussion in 'Himalayan Imports' started by BruiseLeee, Sep 20, 2005.

  1. arty


    Oct 18, 2003
    I have a couple of the Old Hickory knives - and I mean old. They must be about 30 years old.

    They can be sharpened and take a good edge but do not hold it.

    I have some Gerbers with 440C and they are better, but don't hold an edge as well as some old Chef's knives I have. They are French carbon steel Sabatiers, and are nice and gray...but take a good edge and hold it.

    I also have a Sabatier knife that has stainless steel that is so soft it is difficult to get a decent edge on it.

    The carbon steel French chef's knives work much better than any stainless knives I have in the kitchen. I have had them so long that the name is worn off of the handle of one. They are 4 Star Elephant brand that I bought years ago. The only one that seems at all comparable is a Tim Britton custom utility kitchen knife that was made from Sandvik steel.
  2. Bri in Chi

    Bri in Chi

    May 28, 2003
    I purchased a carbon steel Sabatier after watching an Italian chef use one. It's like a musical instrument compared to my German Wustoff - which handles more like a cavalry saber by comparison.
    What has made a big difference was getting a knife block. Now they all don't rattle around together, plus the steel is right there easy to grab for a few licks before starting to work. ;)
    I like kitchen knives. I have 3 hand made ones by Tim Wright that are super. He grinds really thin edges on all his knives, but these are really thin. You can almost read the newspaper through them. Almost, I said :D :eek:
  3. firkin


    Jan 26, 2002
    If the blade is thin, like most kitchen knives, it probably doesn't make any difference. And unless one resharpens often with a coarse stone, a microbevel will probably begin convert to convex with sharpening or honing with finer grits.

    Some Japanese sites seem to show using a very slight microbevel or convexing on the flat side of traditional Japanese single bevel kitchen knives, presumably for durability.

    Don't know about the fancy, hi-tech stainless steel, but in my experience, SS is harder to sharpen, takes longer, but pardoxically seems more "plastic". It seems to gum up the stone, and be more prone to develop a persistant, floppy burr than even a softer carbon steel. I've a laminated Japanese knife with a core of stainless "swedish" steel that is hardened at Rc 61-62 that acts this way. (Only the harder core is getting honed). Yet softer carbon sttel knives like my Okapi don't behave the same way on the stones. Sharpening the Okapi is more similar to sharpening a laminated knife with Japanese "blue" steel for the core. The stainless seems much more prone to chipping too. I have to keep the stainless knife with a less acute edge.

    So in my experience stainless "acts" soft when sharpening, yet takes longer to sharpen than carbon steel that is harder, and chips easier.????

    Carbon steels seem to strop better too.

    I'm converted to water stones, at least for kitchen knives or similar slicers at the upper end of the hardness scale. While there is the hassle of keeping them flat, it is offset by the stones fast cutting action. But at the same time, the ground part appears more polished.

    If one isn't doing a lot of majo re-profiling keeping flat isn't that big a deal. Or use something else for major metal removal. On the couple of Japanese knives I have, the fine water stones work much better for touch-ups than a ceramic steel. I would be quite cautious about using a steel, (smooth only) on very hard thin blades like the Japanese ones, especially stainless. My grooved steel now never leaves the drawer after I converted a (fortunately inexpenisve) hard thin SS paring knife to a se edge with a couple lof swipes. Also, the grooved steel can eat a hollow out of the heel of soft knives with full bolsters because people succumb to the temptation to try and use it as a sharpener when they really should get out the whetstones.

    Someday I'll have to get one of the polished steels.

    And the Henckels are the way they are because that's the way Henckels wants them....Many are made in Japan. Amusingly Henckels seems to have introduced two new lines called "Cermax". Twin Cermax with Rc of 60+ and Cermax M66 with Rc approacing 66 (!) Somewhere there is Japanese website that shows them being harpened with Henckels-branded waterstones.

    Go figure.

    found video:


    Wait for the intro movie to load, click the Cermax knife picture in the middle of the screen. Below the lady in the red dress on man in the black jacket.
  4. kronckew

    kronckew Basic Member Basic Member

    Aug 17, 2003
    very interesting video on sharpening, i did note that the 'dull' knife when he was cutting the tomato, he was pushing straight down, and when he had 'sharpened' it, and re-cut the tomato he used a draw cut.
  5. cliff355


    Apr 19, 2003
  6. firkin


    Jan 26, 2002
    Hmmm...Looked to me like some of the tomato cuts with both the "dull" and "sharp" knife were started with a push cut, and some were started with a draw cut motion. Looked to me like there was more draw-cut motion at the finish with the shapened blade though. But getting through the skin at the start is the real test.

    On the second viewing did notice that the stone seems to have a bunch of dark metal bits embedded in it before he even starts. I find that S.S. seems much more prone to stick to the stone like this instead of staying suspended in the slurry.

    Anyway, the straight "push-pull" method (and from descriptions I've seen, with little to no pressure applied when the edge is leading) seems the be the way the experts sharpen Japanese knives with water stones. I suspect the "figure-8" motion often suggested to promote more even wearing of the stones is applicable to narrow tools like chisels (don't think I've ever seen this motion suggested for plane blades), and has been erroniously transferred to knife sharpening. Woodworkers seem to be the main users of waterstones in the U.S.

    There's some more vids that were linked in a thread on the "other" forum (http://www.knifeforums.com/forums/showtopic.php?tid/746275/) where a bunch of intense kitchen knife knuts hang out:

  7. Bri in Chi

    Bri in Chi

    May 28, 2003
    I don't tell anyone how to run their kitchen. We all have our ideas of what works best. All I can say: In my kitchen, the super-thin blades are for slicing delicate stuff, thicker edges are for hacking through tougher stuff, and really thick, convex edges are for the (Old Hickory)cleaver, or the (Bertha E.) Herter Bull-Chef knife that is convexed and used mainly for making cole-slaw, and hacking through BBQ ribs.That's the big-medicine knife. No dogma, common sense.

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