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Need to make a Fillet Knife, What steel and hardness?

Discussion in 'Shop Talk - BladeSmith Questions and Answers' started by hathegkla, Jun 17, 2010.

  1. hathegkla


    Feb 3, 2010
    My father wants a fillet knife, the problem is I don't know what makes a good fillet knife. I love cooking and fish but I've just never put the two together :confused:

    this is for kitchen use, fish and whatever else he decides to do with it. he's not a professional fisherman or anything like that.

    I know the profile I want to go with but I'm wondering what steel I should use and how hard it should be (I don't want the tip snapping off and hitting someone in the eye :eek:). I have a digital furnace so I can work with both stainless and carbon steel, I've yet to work with stainless but I do have access to plenty of liquid nitrogen if a sub zero quench would help. If someone could recommend some steel and an ideal heat treatment for a fillet knife I'd love to give it a shot.

    I've never ground a really thin blade so I'll likely order enough metal to make a few so I'll be able to practice my heat treatment as well.

  2. Alarion


    Nov 26, 2001
    I'd use 5160, 1 mm thick, scandi grind, 57-58 HRc.
    Say quench in oil and slowly temper to purple-blue for about 30-40 minutes.
    That's the best I can do with my hand cranked coal forge.
  3. hathegkla


    Feb 3, 2010
    cool, I have a bunch of 5160 so its just a matter of grinding it thin enough (or hammering it). maybe the machinist at work will let me use his surface grinder :D

    probably be easier to just buy it that thin though. I was looking at the other thread and considering D2 but my furnace tops out at 1700. my dads glass kiln goes higher but then it wouldn't really be a surprise.
  4. Atlas Knife Company

    Atlas Knife Company KnifeMaker / Craftsman / Service Provider Knifemaker / Craftsman / Service Provider

    Feb 16, 2010
    Personally, I think non-stainless makes the fish taste too oily.

    s30v or something stainless. Fillet knives are around too much water(even stored in the boat) and personally, I wouldn't fillet with anything but stainless.
  5. Johnny Warner

    Johnny Warner

    May 21, 2007
    Stainless receives my vote. I made a few using 1/16" 440C. I used a paint stiring paddle shaped like the knife as a backing when grinding the blade.
  6. hathegkla


    Feb 3, 2010
    not a bad idea :thumbup:

    and I'd love to use S30V but my furnace only goes up to 1700. I should sell it and invest in one that goes up to 2000
  7. mgordon


    Sep 4, 2009
    dont sell it donate it to me.
  8. Dakota 11

    Dakota 11

    Apr 14, 2006
    i have made some good fillet knives out of a2. The last knife i made went to a guy in alaska and it was made from sandivk 12c27. the blade was .100 thinkness so it didnt have alot of flex but it was to be used for bigger salmon. i figure the rc on it was 56-57 and after hacking up a few 2x4's it didnt chip out and was still sharp.

    As to the knife making the fish oily ive never heard of that and alot of old school fisherman swear buy high carbon fillet knives. I think how you clean and when you clean has the most to do with the taste not the steel , and this is coming from someone that fishes the ocean a few times a month.
  9. fastdad4


    Oct 30, 2008
    i just made one out of ats34 3/32 thick ground the blade to 0.020 ths. rc is 59 to 60
  10. CDH


    Jun 8, 2007
    Another vote for stainless steels...

    To me a fillet blade is a hard use blade. I am using ATS-34 because it's reasonably priced, very available, and very corrosion resistant. 440C also meets those parameters. CPM steels are a bit pricey for something I'm likely to drop overboard within 2-3 years...but that's just me!:D
  11. SBuzek

    SBuzek KnifeMaker / Craftsman / Service Provider Knifemaker / Craftsman / Service Provider

    Dec 7, 2006
    I do the same as Johnny,and the paint stir stick is the way to go with any thin knife,either filet or kitchen.
  12. Stacy E. Apelt - Bladesmith

    Stacy E. Apelt - Bladesmith ilmarinen - MODERATOR Moderator Knifemaker / Craftsman / Service Provider

    Aug 20, 2004
    I make a hundred or more fillet knives a year.
    ATS-34 or CPM-154 (Just the PM version of the other) will make a great knife. I use CPM-154 on all fillet knives now. Follow Crucibles HT instructions and you will have no problems.

    I disagree with the 5160 recommendations. 5160,O-1, 1095 are not the best for a kitchen knife ( it may work fine for the pros, but is less than optimum for the novice).

    .060 to .100 are as thick as you need. Flexibility is a function of thickness, not hardness or steel type. If you are making your first fillet knife, I would use 0.100 CPM-154 and taper the blade to about 0.030 at the tip. Flat grind the blade to a very acute edge. This will produce a wicked sharp knife with good flex. For a stiffer knife, reduce the taper.
  13. J.D.


    Feb 12, 2006
    I use 440C, 1/16" thick stock, full flat grind to around .015" at the edge, and shoot for 59-61 RC the same as any other 440C blade, like Stacy said, flex has nothing to do with hardness. My heat treat procedure is, wrap in foil and double crimp edges, heat to 1880 and soak for 30 minutes, plate quench, then temper at 375 for 2, 2hr. cycles, let cool between temper cycles.
  14. Alarion


    Nov 26, 2001
    That's an interesting point that tickles my curiosity.
    I've heard many people say that carbon steel will transfer "taste" to the fish, and it seems reasonable to me. But then, how comes the best sushi chefs in the world use carbon steel blades? :confused:
  15. Stacy E. Apelt - Bladesmith

    Stacy E. Apelt - Bladesmith ilmarinen - MODERATOR Moderator Knifemaker / Craftsman / Service Provider

    Aug 20, 2004
    If you re-read my post I addressed that the pros ( as in "The Best Sushi Chefs") can use carbon steel just fine. They care for their blades, clean them every time they cut with one ( ever watch a sushi chef), and oil them when done for the day. That plus regular sharpening keeps the oxides that alter taste from causing problems. If you cut up the dinner meat, then prepare a salad ( with tomatoes), sit the knife on the sink back, and later on just wash it and put it in the drawer....expect to transfer some sort of taste to the next food you prepare.
  16. Alarion


    Nov 26, 2001
    I read it allright, I was just wondering what actually made the difference.
    So, the oxides it is.
    I own a yanagi-ba and I clean and oil it (with food-grade vaseline oil) immediately after each use: mostly used to cut very thin salami slices :D, and anybody using it on tomatoes will be the next sashimi in the bento. :p
  17. hathegkla


    Feb 3, 2010
    man, I really do need to upgrade my HT oven. it can only do 1700 and has trouble coming back up after opening the door at that heat. its a great Paragon kiln if you do glass but I guess I need a 2000F furnace if I want to do anything other than regular carbon steel.

    so I started making the knife out of 1095, I'm just gonna give it a shot because I can't heat treat stainless. hopefully I can sell my kiln or trade it in for a higher temp one.
  18. John L

    John L Gold Member Knifemaker / Craftsman / Service Provider Gold Member

    Oct 28, 2004
    I have a littel knife shop in Baja California Sur...Mexico and the captains here want a stiff knife for cleaning fish...not your typical 1/16" very flexible blade. The fish here tend to be large...10-50 lbs or so. I beleive it all depends upon the intended use. I make mine out of D2 or CPM154 and about .125" thick.h micarta handles....good and grippy.

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