HT recipe for sawblade mystery steel to make Santoku?

adinb114

adinb114

Joined
Feb 25, 2011
Messages
651
Hi folks,

Let me start of by saying that I recognize that the post title is a bit of an oxymoron, but it seems like i'm stupid enough to try this anyways. :)

I've got my hands on a sizable piece of 1/16" bandsaw steel. After some reading, i've found that old saw blades (without carbeurized inserts) are often 15n20 or 10XX.
I know that HTing mystery steel is a crapshoot, and i'll more than likely end up trashing this and buying a piece of steel from Aldo, but considering that i'm on vacation and have the steel on hand, i figured it's worth my while to give this a shot.

My HT gear consists of a charcoal forge, toaster oven w/oven thermometer, and canola oil.

So here is the plan for HT.

Profile and drill a 5 inch blade santoku.

Heat to non magnetic then anneal in wood ash.

heat to non magnetic + a little, then quench edge first in warm canola.

Temper for 1 hour around 350.

Grind in convex edge and test on brass rod.

Temper twice more for one hour cycles, bumping temperature up 25 degrees as necessary until edge flex test provides adequate results.

My main questions are:
1) Is it necessary to anneal multiple times?
2) Should I anneal at non magnetic or slightly hotter?
3) Should I quench multiple times?
4) For this style of knife, should I just edge quench, or quench edge first, then quench the entire blade.

Thats about it.

Thanks for your help.
Adin
 
I would skip the annealin in ash. Just heat to non-magnetic (or slightly hotter) and air cool to black - repeat 3 times. Then proceed to the austinizing heat and quench. Personally I would only quench once, after trying too hold it at temp for several minutes. If you quench the whole blade then temper it won't take a set/bend that an edge quenched blade would in steel that thin.
 
I would go with a full quench and draw the spine back to a spring temper. As Bruce said this keeps it from bending and taking a set, instead with a spring temper it can bend a bunch and go back to original shape, plus it helps avoid cracks and things of that nature which from what I under stand is good with kitchen knives since they are so thin.
 
I would do a HT on the steel prior to any drilling or shaping, make a few small rectangles and try your HT to see how well it works, once you have the HT, then profile.

You can spring temper with a propane torch, keep the edge in a pan of water and heat the spine to purple color. It takes a lot of patience, heat a little remove the heat and see how the color develops. I suggest once again trying on scrap to see just how the heat develops.
 
Patrick is giving excellent advice.

If you have a large piece, use several 4" long pieces to test your HT and practice drawing the spine.

Don't use the ash anneal...just do as Bruce advised and triple stress relieve.
 
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