Removing steel from the spine at the tip

Discussion in 'Shop Talk' started by labor of love, Mar 25, 2020.

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  1. Mar 25, 2020 #1

    labor of love

    labor of love

    labor of love

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    I have this blade that I’m looking to modify. I want to take off 5-10mm from the tip area and take a lot of steel off the spine. Basically, the tip is too high. I can lower the profile by recreating a new lower tip by taking off some of the curve right before tip.
    Does that make sense?
    Anyway, I plan I’m using 240grit+320grit stones to do this. Any advice would be much appreciated.
     
  2. Mar 25, 2020 #2

    labor of love

    labor of love

    labor of love

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    The tracing on the right is what I’m attempting to do. 3FF73F8D-E02A-4205-A3D1-FEC626D7D34D.jpeg
     
  3. Mar 25, 2020 #3

    ian

    ian

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    Hey, drawing it is the hard part, it’s a cake walk from here. ;)

    I’ve done this on a few cheap knives. Generally you’ll want to start by moving the spine on the stone in the direction perpendicular to the face of the knife to remove as much metal as fast as possible. 90 degree angle to the stone would be fine, I suppose, although I usually find it easier to do like a 60 degree angle and alternate sides. This can leave the spine faceted, so you’ll also want to do some breadknifing of the spine to remove faceting and help get the exact curve you want. You’ll also need to round the spine afterwards to make it not look like ****. I usually do this starting on a stone, and then I switch over to the shoe shine sandpaper method. You will probably need to do some thinning near the tip afterwards, too, since the convexity of a knife often decreases towards the tip.
     
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  4. Mar 25, 2020 #4

    labor of love

    labor of love

    labor of love

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    Is there any trick to keeping a proper curve to the spine above the tip? I guess just reshaping after the steel is removed.
     
  5. Mar 25, 2020 #5

    The Edge

    The Edge

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    To do most of the work, use a brick instead. It's going to eat through your stones very fast unless they're diamond Feel free to draw on the knife (if you weren't already planning to), and be sure to check your work, as you can't put metal back on.

    I've done this many times on both stones and grinders. I like to work small sections at a time, then do blending strokes to make sure everything isn't jagged, and finish by deburring and easing the corners.
     
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  6. Mar 25, 2020 #6

    ian

    ian

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    That’s not hard to do with breadknifing, in my experience. It’ll make your job easier if you try to make it as smoothly curvy as possible in the first step, though.

    Obviously I’m not the one to listen to in this thread though. :)
     
  7. Mar 26, 2020 #7

    labor of love

    labor of love

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    I have 2 different grit files. Is that what you would use at the end for deburring and easing the corners? Maybe files then the side of a stone then some sandpaper?
     
  8. Mar 26, 2020 #8

    ptolemy

    ptolemy

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    I did something similar on a Henckels chefs with serrations in the middle. I spent maybe 30-40min grinding them down on 240grit. Then, a bit of time making it even. Worked knife. But, I also wasn't looking for great finish, just usable result.
     
  9. Mar 26, 2020 #9

    The Edge

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    To round the corners and refine, I'd move to your stones after all the heavy lifting was done. Just no point wasting expensive stones when a brick costs me 67 cents. With the tip being thin, you won't need to spend a ton of time making everything perfect. You just don't want a burr catching you, or having sharp corners.
     
  10. Mar 26, 2020 #10

    labor of love

    labor of love

    labor of love

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    The knife Im about to tweak is pretty pricey ($560ish)
    I’d send it back to the maker, as he’s pretty cool, but I think he closed his shop for the time being.
     
  11. Mar 26, 2020 #11

    ptolemy

    ptolemy

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    My only concern is that if you modify it, it maybe yours forever unless you really think you can do a great job. To me, it wasn't a concern with a $30 knife.
     
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  12. Mar 26, 2020 #12

    labor of love

    labor of love

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    C8DCDC6B-1AB3-4413-91C4-DC17E045E6B2.jpeg Will this work?
     
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  13. Mar 26, 2020 #13

    labor of love

    labor of love

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    Yeah, 4-8 monthes now I could likely get the maker to look at it if I’m not happy with my progress.
     
  14. Mar 26, 2020 #14

    The Edge

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    That would definitely work.

    If you're worried about messing up the knife, and you know the maker, it would be a good idea to shoot them a message. I'd like to modify my own work if someone wasn't completely happy, but it's understandable if you're in a hurry, or just looking for a project.
     
  15. Mar 26, 2020 #15

    drsmp

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    ED61EFA1-3022-43A0-A882-C6A3839BA938.jpeg Ken Onion Work Sharp does a quick job. I take the edge guide off and rotate the belt for a mini belt sander. Like $150 new. You can also polish and round the spine with the finer belts. Lift the the tip up at mid belt to keep from clipping it off. Work perpendicular to the belt. The machine has a lock out button so you don’t have to hold the trigger and it frees up both hands. Way quicker than stones/diamond plate and you can get whatever shape you’d like. I use blue masking tape (cut to the shape I want) on the blade to protect the finish and also as a template.
     
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  16. Mar 26, 2020 #16

    labor of love

    labor of love

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    I’m speaking with the maker right now sounds like he is still open for business, his shop just happens to be closed to the public.
    If nothing else this thread was educational.
    I likely won’t attempt modding it in my own now.
     
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  17. Mar 26, 2020 #17

    panda

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    What about a Dremel?
     
  18. Mar 26, 2020 #18

    Benuser

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    Not different from a common tip repair.
     
  19. Mar 26, 2020 #19

    drsmp

    drsmp

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    Dremel’s walk/kick really easily and you can easily mess up your blade, I wouldn’t recommend that tool for this job
     
  20. Mar 26, 2020 #20

    VICTOR J CREAZZI

    VICTOR J CREAZZI

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    I was going to say that 'this is a really simple and fast job with a belt grinder'.
     
  21. Mar 26, 2020 #21

    Carl Kotte

    Carl Kotte

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    Not a super knife, but metal file (plus a mask) and paper works. But it’s not very fun.
     

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  22. Mar 27, 2020 at 3:07 AM #22

    bahamaroot

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    Nothing's fun with a Global!
     
  23. Mar 27, 2020 at 3:17 AM #23

    dafox

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    How bad can it really be?
     
  24. Mar 27, 2020 at 6:22 AM #24

    Carl Kotte

    Carl Kotte

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    I don’t mind them. Until I have to use a file...
     

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