Page 2 of 5 FirstFirst 1234 ... LastLast
Results 11 to 20 of 47

Thread: How to identify grind issues

  1. #11
    Senior Member shankster's Avatar
    Join Date
    Mar 2011
    Location
    Toronto/Canada
    Posts
    506
    Quote Originally Posted by Dave Martell View Post
    If it says Moritaka on the blade.
    Boo and ouch dave.that was a low blow...

  2. #12
    Delbert Ealy's Avatar
    Join Date
    Feb 2011
    Location
    Indian River, MI Just under The Bridge
    Posts
    1,069
    Quote Originally Posted by mhlee View Post
    Del:

    It actually has nothing to do with either you or Moritaka knives. I don't own one of your knives or a Moritaka.

    Actually, it's just something I've been thinking about for a while now, and something that I've been very curious about. I exchanged some e-mails with Tinh recently and we briefly discussed this. I just wanted to learn how to identify grind issues on my own.
    Michael,
    Thanks for clarifying, I would love for all the members here be able to recognize potential problems in a knife upon close inspection, maybe even at a glance. Grind issues and even bent blades can be hidden in pictures, but not easily in person. Bent blades have absolutely no excuse, if the blade is not straight, that happened at the time of heat treating and should have been rectified then, they don't warp after just sitting there, especially after tempering. I have had blades warp in heat treat and I fixed them, sometimes warping badly enough that I am required to go through the whole process again. Most of the knives you guys use are so hard that it requires a great deal of force to bend them on purpose, let alone by accident. Some of the knives with softer cladding may be a little more subject to bending or taking a set, but it still takes a lot of force and determination to do.
    Twisted blades are more often than not a result of uneven grinding, especially in full flat or full ground, but slightly convexed blades where it is harder to see than on a partially ground blade. It is easy for a person who is strongly right-handed to grind knives with a slight twist to them, especially at the tip. In this way many left-handers have an advantage, because in our right-hand dominant society, they are forced to use their right hands more. I long ago learned this lesson and grind almost as well left-handed as right. I can't swing a hammer as well with my left, but I do grind with both.
    Even grinding comes only with practice, there is no other way, you practice until it is correct. I was surprised when Dave first broached the subject of the overgrinds as you have come to know them. They are present in the larger knifemaking community, and are most freqent among new grinders. I was amazed to hear of this occuring in kitchen knives.
    Grinding a knife to thin I have already addressed in my subforum.
    Specific questions are always welcome.
    Thanks,
    Del

    Laminated metals specialist, Kitchen knife and gadget maker
    www.ealyknives.com
    www.mokume-jewelry.net
    "Build a man a fire and he will be warm for a day, set a man on fire and he will be warm for the rest of his life"

  3. #13
    del... i've seen quite a few knives warp just sitting there... both clad and unclad

  4. #14
    Delbert Ealy's Avatar
    Join Date
    Feb 2011
    Location
    Indian River, MI Just under The Bridge
    Posts
    1,069
    Jon,
    I am speechless(well almost) I have no idea why that should be. Its never happened to me. It should not happen at all, I'll have to think about this. I may PM you later about that subject.
    Thanks,
    Del

    Laminated metals specialist, Kitchen knife and gadget maker
    www.ealyknives.com
    www.mokume-jewelry.net
    "Build a man a fire and he will be warm for a day, set a man on fire and he will be warm for the rest of his life"

  5. #15
    Quote Originally Posted by JBroida View Post
    del... i've seen quite a few knives warp just sitting there... both clad and unclad
    another example of the unexpected for me - been reading about this happening to some kitchen knives;
    it started with wood expanding, contracting, needing to be stabilized;
    then it was some wine need be de-cantered to open-up and become tasty (doing that now for dinner )

  6. #16
    sure

    obviously with clad single bevel knives, its different, but with clad double bevel knives, it can often be because the thickness of the cladding is different on each side and causes warping (especially when the steel has not been allowed to rest... whatever that process is called where the internal forces are "tempered" so to speak)

    single steel knives are often a result of the steel being improperly heat treated in my experience, so if your heat treat is good, i guess you wont see it too often.

  7. #17
    With all due respect(which is certainly a lot) to Japan, I have heard tell that traditional Japanese smiths often are not taught to fully understand and respect the annealing process, it's more a heuristic kind of thing, and leads to incomplete or uneven heat treats being more common(though many smiths don't let it past their QC). I've seen pictures of shops that have literally hundreds of knives that rest for months before sale because the steel is still shifting and settling, and late warpage is common enough to warrant the wait.

  8. #18
    Senior Member goodchef1's Avatar
    Join Date
    Apr 2011
    Location
    Honolulu
    Posts
    249
    as far as the "no excuse for the bent blade" thing, does the maker forget to check the straightness of the blade? or is it due to just lack of attention and/or care? I also heard that clad combo steels can warp by just sitting there for awhile, which is why I only get single steel blades now. No experience myself, but I don't want to take any chances with finding about it later in the future. Is it a given for them to warp? or is it the unlucky few who come across this?

  9. #19
    for what its worth, i've seen this in both japanese and american made knives... heck, even some german and spanish knives

  10. #20

    Join Date
    Mar 2011
    Location
    Houston TX
    Posts
    1,320
    Quote Originally Posted by shankster View Post
    Boo and ouch dave.that was a low blow...
    +1 not cool... not cool at all!!!!

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •