How To Fix a misshapen tip?

Discussion in 'Shop Talk - BladeSmith Questions and Answers' started by MJTX, Mar 19, 2020.

  1. MJTX


    Mar 17, 2020
    Hi all,

    I'm making my first knife and the tip is curved off to the left. The knife is a chef's knife for my daughter made from 3/32 15N20. I don't have a grinder, just files and sandpaper.

    Any suggestions on how I can true up the point without going too thin? It's not heat treated.

    Hopefully the photos will also show that the last 1/4 inch or so slopes sharply to the point, which is veering left.

    Ken H> and DustinY like this.
  2. MJTX


    Mar 17, 2020
    Sorry about the gigantic photos. First post and first knife.
    DustinY likes this.
  3. Bill DeShivs

    Bill DeShivs KnifeMaker / Craftsman / Service Provider Knifemaker / Craftsman / Service Provider

    Jun 6, 2000
    Bend it.
  4. robwil


    Aug 18, 2007
    Is this before or after heat treating? How did it appear?
  5. FredyCro


    Jan 11, 2019
    Lever the tip pre HT in a vice and counterbend it slowly. You can also tap with a wooden mallet on a hard surface. In any case wrap it in a softer material like leather or similar to not gouge it or scratch it. When it looks like it is centered, use a drill bit of the same size as your stock thickness on a flat surface to draw a center line on the spine, and file/sand away till you have equal grinds on both sides.
    MJTX likes this.
  6. FredyCro


    Jan 11, 2019
    You might also need to reshape the tip somewhat to gain some material back. Don't sand over the tip of the blade, stop before it looks like you are there or you will round it too much. Sorry if I am saying obvious stuff, I am a newbie myself.
    TheEdge01, SHostetler and MJTX like this.
  7. MJTX


    Mar 17, 2020
    It's not heat treated. It's not bent. My bevel filing isn't symmetrical. I keep messing with it and I'm concerned that I'll mess with it too much.
  8. timos-

    timos- KnifeMaker / Craftsman / Service Provider Knifemaker / Craftsman / Service Provider

    Oct 22, 2012
    you overground one side, its very easy to do. since you cant add the material back youll have to over grind the otherside to match it. Then go back to evenly grinding both sides until you get the right shape. Or, you can get it heat treated and correct it by hand with a 140 grit diamond plate. The plus side to doing it the latter way is that you can get out your cutting board and the plate, and cut stuff up, grind on the plate, cut stuff, until you get the performance you want. Focus less on perfect symmetry, that comes with experience.
    TheEdge01 likes this.
  9. TheEdge01


    Apr 3, 2015
    I’ve made the same mistake and will probably do it again in the future. Like timos- said, grind away carefully until both sides match.
  10. Hubert S.

    Hubert S.

    Dec 14, 2019
    I find it difficult to get both sides even with a file when the tip starts flexing. I have used a 140 diamond plate on a couple of knives and it helped to even things out, but it is slow going after heat treat. I would fix as much as I can before heat treating if working with hand tools.

    The blade profile looks like it is perfectly straight for about half its length before it starts curving to the tip. It looks a bit odd to me, but I just started making knives and do not know too much about knife geometry. Just rocking it back and forth on the workbench will probably tell you if the profile is right or not.
  11. Cushing H.

    Cushing H. Gold Member Gold Member

    Jun 3, 2019
    Ditto (from what I can see) on the overground on one side. You need to grind more on the left side to even up (blade will be shorter but even). Get some machinists blue dye and scribe the centerline on the spine so you can clearly see where you want to end up as you remove metal.

    Nice looking knife! I’m sure your daughter will love it!
  12. Kali4nia


    Aug 12, 2015
    Are you scoring lines on the blade edge? Use a height gauge...or just a drill bit in similar thickness to the blade stock. Dykem and mark. Blue dykem to be specific ;)
  13. Cushing H.

    Cushing H. Gold Member Gold Member

    Jun 3, 2019
    Too late to score the edge... which is why I recommended defining the centerline on the spine. Better than nothing...
  14. FredyCro


    Jan 11, 2019
    I would still double check if it is also slightly bent. Put the knife on the flatest surface you have, press on the middle part of the knife spine, look where your center line on the back is, notice the material at the tip from the centerline and how the tip raises from the surface. Do it on other side. I just had the same problem the other day and sure the grinds weren't 100 % even either, but the tip bent slightly while grinding without me noticing it.

    If you are still sure it is uneven ground, reshape the tip and try again. You could drop the spine and easy the belly a bit, you wouldn't lose more then half cm and it would be easier to see where the problem areas are.
  15. Scott Hanson

    Scott Hanson Moderator Moderator Knifemaker / Craftsman / Service Provider

    Sep 6, 2014
    I think I would leave it alone, give it to your daughter and let her enjoy using it, then work on making the next one better.
    TheEdge01 and Jasoncap like this.
  16. TheTourist

    TheTourist Basic Member Basic Member

    Jun 23, 2019
    I would first tap the tip into proper alignment and then 'dress' the edge with a light polishing. Many of the knives I get from clients also have damaged tips. The overall idea is that if you grind something off it is "permanently gone."

    It's like fixing a dinged fender. Tap the big stuff out first with decreasingly lighter tools, like a rubber hammer. I've seen body and fender men do this, and the bondo that they use on the last few step looks like a tiny white smear when they sand the area to match the fender.
  17. MJTX


    Mar 17, 2020
    I defined the centerline on the spine like you suggested. It revealed that the last inch of each bevel were very different. I redesigned the tip and am working on cutting it out (hacksaw).

    Thanks for the help. I’ll post an update after I make some progress. Worst case is that my daughter ends up with a paring knife and I gain some experience.
    FredyCro and Jasoncap like this.
  18. Natlek


    Jun 9, 2015
    This is what i would do ..................
    MJTX likes this.
  19. i4Marc


    Oct 19, 2011
    The OP says the blade is not heat treated yet. Bill is correct, just bend it.
  20. MJTX


    Mar 17, 2020
    I've already began the cutting process for a redesigned tip but this is great! What software did you use? I have a feeling I will be in this situation again.

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