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Straightening A Bent Blade.

Discussion in 'Working the Steel' started by Grahamm, Apr 8, 2017.

  1. Grahamm

    Grahamm Active Member

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    I gave my friend a couple of blades to heat treat and although he is a great machinist he can be a bit rammy. So when the blades didn't fit in, rather than reposition he just gave the door a little shove to close it.
    So I ended up with some blade-a-rangs.

    I tried to bend one back by hand and now I have a 2 part weld your own handle on kit so I'm not gonna do this one.

    Short of taking the torch to it and re-treating it, is there any other option?
    Thanks.
    [​IMG]
     
  2. John Noon

    John Noon Well-Known Member

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    I tried a piece of HSS with one side cut off and holes cross drilled with bolts to act as blade straighteners then put in the furnace for a temper cycle. Results were not that good in reality but I was only doing a 400F temper at the time.
    Not much help but it is supposed to work mind you I was dealing with AEB-L which loves to be in a curve of some sort.
     
  3. Grahamm

    Grahamm Active Member

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    Well, I can confidently say that this didn't work either.
    [​IMG]
     
  4. John Noon

    John Noon Well-Known Member

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    Right about now I would be welding on a stainless steel rod for a hidden tang handle
     
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  5. Icho-

    Icho- Staff Member

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    Been there. I turned mine into a folder.
     
  6. Grahamm

    Grahamm Active Member

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    A folding Santoku would be very interesting. Gonna try to weld a 4 inch piece of steel on and go wa handle if I can. I'm a horrible welder so maybe I will just stick the rod to the steel and glue the welding rod into the handle. I only have a little crappy 110 V arc welder. Keep watching. I have a good feeling how this is gonna end....
     
  7. John Noon

    John Noon Well-Known Member

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    preheat the blade to it's tempering temperature before welding allow to cool very slowly before repeating the heat treating. An normalizing or spheroidized annealing cycle would be beneficial before quenching again.
     
  8. Grahamm

    Grahamm Active Member

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    Well, I doubt it would pass your inspection but here's what I did.
    [​IMG]
    I wrapped the blade in wet towels and it tested 56 RC about an inch from the weld. I'm gonna leave it and not reharden since the blade wouldn't have gotten hotter. It's just gonna stay at my house anyway. Thanks.
     
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  9. John Noon

    John Noon Well-Known Member

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    Now that looks real nice
     
  10. Grahamm

    Grahamm Active Member

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    Thanks. I ended up doing it at my buddies shop since he has a much better welder than my silly little arc welder. I was given it and have actually never been able to get it to work. But it's also been 20 years since I did any arc welding either.
     
  11. Grahamm

    Grahamm Active Member

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    I forgot to mention that I also took the other one, the one bent in the photo above and took the torch to it, got it much straighter and then rewrapped in stainless wrap and retreated it. I will post a photo but it's more like a 1/8 warp now than a 1/2 inch. Not perfect but nothing I do is ever perfect. Everything I do is learning as I go so I'm happy with how it came out. The lesson was learned back at the original heat treat.
     
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  12. Rick Marchand

    Rick Marchand New Member

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    Next time try to straighten during the temper. Clamp it straight and throw it into a preheated oven @400 for an hour. Quench in water and see if it set.
     
  13. Nieman Knives

    Nieman Knives New Member

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    Can someone recommend what I should be purchasing to “hammer straighten” my heat treated AEB-L knives?

    I’ve seen a couple videos on it and I tried it just holding a cheap masonry bit in my hand and using a hammer with the other and it actually worked...but I ended up destroying the cheap bits that I had lying around (they were already in rough shape from drilling concrete)

    Should I just buy more masonry bits and if so is there a good brand that will hold up and be hard enough (can’t see hardness listed on any I look at)? Are there any types of small flat edge chisel with an actual carbide bit?
     
  14. John Noon

    John Noon Well-Known Member

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    If you are hammering on a drill bit you can be sure they will all shatter.

    I have tossed in the towel when it comes to straightening a warped AEB-L blade. Much easier to start over and save the headache.
     
  15. Nieman Knives

    Nieman Knives New Member

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    I’m sending them away for heat treat in large batches (20) and sometimes they are coming back with warps. This last batch came back with about 6 of 20 with minor warps. Not worth it to send them back if I can make this method work and so far with the couple I tried it on, it worked perfectly...just need better (or perhaps unused) bits or other chisel type tools that will hold up. Any recommendations on carbide chisels or good quality bits would be greatly appreciated.
     
  16. John Noon

    John Noon Well-Known Member

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    You can get round bar tool steel at fastenal or other industrial suppliers.
    What straightening method are you using
     
  17. Nieman Knives

    Nieman Knives New Member

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    From what I understand the tool steel will not be hard enough to do this method. My AEB-L is 61hrc.

    I am making dimples in the cupped side with a hammer and carbide tipped concrete drill bit.

    Again, so far it is working perfectly. Just looking for recommendations on good carbide bits or perhaps a small carbide chisel. The bits I used were used for drilling through concrete already and were in bad shape to start with.
     
  18. John Noon

    John Noon Well-Known Member

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    Okay for this I would use a HSS T1 18% (Tungsten) it can be used in chisels and punches.

    I have old planer blades here that can be made into a chisel easily and a punch with a bit of finesse.
     
  19. Nieman Knives

    Nieman Knives New Member

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    Just thought of something...

    if I used the dimpling method to straighten a blade, which worked really good, what will happen if and when I grind out the dimples??? Will it just warp back to the way it was again now that the dimples aren’t there to ‘push’ it straight???
     
  20. John Noon

    John Noon Well-Known Member

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    Grind away, below surface deformation is hold it in place. Even if ground to the bottom of the dimple there is still compressed metal below
     
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