• Neil Yeager
    21
    What do you guys do fo pre-grinding prior to heat treat. I only work with carbon steels, and have been doing some pre grinds for the bevels, but I am really thinking that I will eliminate that step and wait till after HT.
  • Jeff Kushen
    47
    Hey Neil,

    As with anything, 'it depends'.

    For me the answer is even for carbon steel, if it is very thin ,like a Chefs knife or EDC (I tend to do anything 3/32" or less) I grid POST HEAT TREAT. Its not that much more difficult with sharp belts, and it lessens the chances of warping.

    For normal stainless steels (12c27, AEB-L, ant the like) I grind all post heat treat. For thicker carbon and super steels, I grind pre-heat treat. I can't imagine the amount of effort and belts used to grind a CPMS35V or some 'super-steels' after heat treat...

    Ultimately, it depends on YOUR grinding style! If you are heavy-handed, grind after. if you use light passes and dip often you may be able to get away with doing it before.

    And always normalize / thermal cycle before heat treating. I bought a couple 1" thick aluminum plates, that I put into my bench vise, and if I am worried or have a feeling about it warping, i clamp it in the plates when I pull it out from thermal cycling.

    YMMV.
  • Rix Raven
    15
    I tried both ways and I find that (like Jeff) it lessens potential warp if I grind after HT. Specially if its layered. And with a fresh coarse grit it will not take long to take off the excess weight.
  • JR Knifemaker
    76
    If it’s a shorter knife, say a hunter/bushcraft then I’ll always lay the foundations before heat treat, as long as I’m leaving 1-2mm at the edge (not sure what that is in imperial, but about the width of an ant!!)
  • Finn Leslie
    1
    I usually do a fair chunk of the grinding beforehand. Saves time since I don’t constantly have to dunk the blade to keep it cool and the belts grind MUCH faster on annealed steel. Thinner stock I do less grinding beforehand to cut down on warping but thinner knives are usually quite a bit easier to correct warps anyways.
  • Neil Yeager
    21
    Ha, but we got some Big A.... ants here in Thailand.
  • Neil Yeager
    21
    Thanks for all the comments. I am going to try a small batch w/o pre grind and see.
  • JR Knifemaker
    76
    go by the nice small British ant!
  • Neil Yeager
    21
    Are your ants metric or imperial there?
  • JR Knifemaker
    76
    metric. Sensible metric ants.
  • Bryn Davies
    10
    "the width of an ant"! I fucking love it! All metric to imperial conversions should henceforth be translated into invertebrate comparisons.
  • JR Knifemaker
    76
    we can all identify with an ant’s width.
    We can then upscale and downscale
    Bees. Woodlice. House spiders. Much more international standards of measurement.
    Unless you live in Australia.
  • JH Forgeworks
    3
    Anything under 1/8th inch I'll just break the 90's and do my grinding post heat-treat. The exception being smaller edc type blades with less than a 3.5 inch cutting edge. Those usually carry a thicker unground spine so warping is less of an issue. I won't take them to final thickness but will do about 60-75% of the grinding pre-heat treat.

    I find that, even with carbon blades, I'll use a pair of 1.5 inch aluminum plates in a woodworkers vise. For carbon steels I'll quench in Parks then transfer to the plates. This has considerably minimized my warping issues even on loner 8+ inch chefs blades. I actually just did a 1/16th inch 8.5 inch fillet knife and managed to bring it out of the quench dead flat using this method. Ground everything afterward.
  • JR Knifemaker
    76
    this is a great idea with plates post quench. I’ll give that a go!
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