Thursday, July 5, 2012

How To: Making a Kiridashi.

#1. Start with a suitable piece of steel. I’m using a piece of 1095, approx., 1/8 x 1 x 6 inches long, with a slight taper in width already in it.

#2. Texture one side with a texturing hammer at a forging heat.

#3. Hot chisel a groove in one end at about a 45 degree angle and snap it off in a vice, cold.

After the forging sequence, normalize and stress relieve the 1095.

Recommendation: For 1095, normalizing and stress relieving should be sufficient. Annealing should be done subcritical with a spheroidizing regime if necessary. Avoid slow cooling from above critical.

#4. Stock reduction: File or grind the profile and bevel. Drill a hole at the back end and sand.

Tip: Prior to stock reduction descale the piece with jeweler’s picking compound (sodium bisulfate) or vinegar. Vinegar will work fast if you bring it to a boil, but be sure and do that outside because of the fumes. Also, be sure and do it in a non corrosive container. A ceramic crock pot works well for this. Jeweler’s pickling compound may also be used hot, but it tends to work relatively fast at room temp. Removing the hard iron oxide scale before stock reduction will help save on files and abrasives.

#5. Harden and temper the Kiridashi.

Note: For heat treating specs, click here.

Recommendation: For quenching/hardening sections of 1095, 1/8 inch thick or under, use eco friendly canola oil at 120-130 F degrees. For more information, click here.

Temper at 425 F degrees for one hour and cool to room temperature, 2-3 times.

#6. After heating treating, pickle it again to remove oxidation. Next, rub it with finishing pads first, then extra fine steel wool impregnated with MAAS polish crème to bring up the luster. Use a heat patina (optional) done with a torch and be sure to use a vice as a heat sink so as not to over heat the edge and lose the temper. Lastly, sharpen the edge (no secondary bevel).

4 comments:

  1. Tai, did you full quench that?

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    Replies
    1. On these, either a full quench or just quenching the working end is fine. On this one, I quenched about one half the length from the working end and drew the third temper (from the heat patina) through the transition area.

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  2. When heating for quench how long should I soak the higher carbon steels like 1095?
    I think it was important for steels like 5160 to soak longer?

    ReplyDelete
    Replies
    1. 10-15 minutes should be fine for 1095 and/or 5160.

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