Knife #2 Santoku - Projects - Audio Artillery

Knife #2 Santoku

  1. Intro
  2. Handle Construction
  3. Handle Finishing
  4. Blade
  5. Heat Treatment
  6. Finished

1: Intro

8" santoku in 1095 with ebony and padauk handle.

Stats, specs, and records
Blade7" long, .100" thickSantoku-style vegetable
Blade finish
Steel1095 carbon steel
Hardening10 minutes @ 790 C (1454 F)
QuenchCanola oil @ ~130 F
Tempering30 min @ 204 C (400 F), 60 min @ 204 C (400 F)Target hardness = 62 RC.
HandlePadauk and ebony, octagonal style
Handle finish


2: Handle Construction

Small brass locator pins allowed me to work the handle as one piece and still disassemble for fitting. The pieces started as roughly 1" square blocks but by the time they're planed flush they're more like 7/8". Overall length is around 5".

(click for full size)

(click for full size)

The rectangular slot to accept the blade was cut by chiseling a V indentation the size of the blade and then drilling with a 3/32" bit to remove material. The V shape keeps the bit from wandering. Then some file and chisel work to get it just right. For something this fiddly it wasn't that hard to get right..

(click for full size)

(click for full size)

The corners were knocked off with a hand plane. Later they'll get rounded a bit to remove the sharp edges.

(click for full size)


3: Handle Finishing

To be done...


4: Blade

I forget exactly what I ordered but what I got was around .100" thick 1095. It had slight bends on both long ends that meant about .01" had to be ground off one side to make it flat. Next time I should not order steel that is just wide enough since there seems to be some flatness issues at the extremities.

The below pics are after 120 grit belt on the 1x30 followed by hand sanding at 100 and 220 grits. I think it would have been faster to use a 240 grit belt. Most of the time was spent getting the 120 grit belt marks out.

(click for full size)

(click for full size)


5: Heat Treatment

Now that that blade is all pretty it's time to burn that pretty finish off.

I'm still confused about the one way to heat treat 1095. Everyone seems to have a slightly different recipe. Nearly everyone hardens at 1475 F. The hardening range is 1440 - 1475 F. There is a bizarre spread of tempering temperatures around the internet. Does it depend on the hardening temperature? Does it depend on the amount of time spent tempering? I don't know.

Cashen seems reputable so I've gone with a 400 F tempering temperature in hopes of getting around 62 RC in the end.

But that's not the only aspect with conflicting information. I'm quenching in 130 F Canola oil. Some people say that Canola is better than professional quench oils. Others say it's impossible to get the full hardness of 1095 with Canola because it is too slow. They may both be right, the outside of the steel probably cools fast enough to maximize hardness but the inside may not -- and this is ok. How does this affect the tempering? I don't know.Nice layer of carbon after the quench:

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And after tempering:

(click for full size)

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