Author Topic: Heat treatment  (Read 12311 times)

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Offline Morgan

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Re: Heat treatment
« Reply #15 on: May 21, 2021, 11:32:49 pm »
Thanks for all the great info guys... really helpfull :)

I’m thinking I’ll play around with the spring steel for a while but maybe will eventually buy some 1084
That’s a good plan. You have a lot of the springs, beat on em and learn.

Offline Fox

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Re: Heat treatment
« Reply #16 on: May 22, 2021, 05:41:54 pm »
 :)
Why must we make simple things so complicated?

Offline Pappy

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Re: Heat treatment
« Reply #17 on: May 23, 2021, 06:13:20 pm »
I use them for everything, gave several away and they are happy as I am with the edge they hold, and old friend of mine that does a lot of knife sharpening said they feel like as he sharpens the old Case xx fairly easy to sharpen but hold a good edge, not to hard is what I like.😉 Pappy
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Offline Mr. Woolery

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Re: Heat treatment
« Reply #18 on: September 02, 2021, 01:58:58 am »
I use 1095 and have for over 20 years.  It is not the absolute best steel out there, but it is a good steel. 

My recipe for heat treatment is essentially what Wayne Goddard recommends for a simple steel.  I work in batches of anywhere from 4 to a dozen.  I'll give my recipe here:

First, you want to normalize it.  I do this twice.  (This is a matter of heating it slowly and evenly until it won't stick to a magnet, then taking it just a tiny bit further.  Some people will melt salt on the blade surface, but I haven't tried that.  Then air cool it.  I just hold it in the tongs and let it cool until all the glow is gone with my shop lights turned off.  It will still be hot enough to burn you, but I go back into the fire and repeat, then lay it on a soft fire brick to cool to room temperature.  The goal of normalizing is essentially stress relief.  It reduces likelihood of warping in the quench. 

Before I harden any blades, I heat my oil.  I use a goop quench made of canola oil, bacon fat, and candle wax.  It is a soft solid at room temperature (like Crisco), but I heat it up until it is nice and liquid.  This is about 130 degrees.  I just use a railroad spike, heat it up in the forge and put it in the goop until cool.  Repeat a total of three times (you need to check your own quench container, don't take this as gospel - it is only true of my setup).

Then the sexy part!  Hardening!  Slowly and carefully heat the blade up to nonmagnetic.  I like to have low light so I can see the color in the steel.  I always check with a magnet.  I know some people claim they can tell just by looking, but I'm not able to get the consistent results I want that way.  Once it is not magnetic, I keep it moving through the fire until I'm certain the color is the same through the whole blade.  This is easy to see by eye.  But be really careful about the tip.  It is super easy to get it a lot hotter than the rest of the blade.  This is a matter of practice, I find.  Get to know your own forge for best results.

Now, you have about one second to get that steel under 400 degrees.  Get it in the oil.  I quench edge down, personally.  I like to keep the spine of the blade up out of the oil so it doesn't get hard with the edge.  Once the glow is gone from the spine, I put the whole blade in the oil and let it cool for a few seconds (about 20-30 seconds for a smaller blade, up to a minute for larger blades). 

Pull it out and wipe the oil off with a shop rag.  A good hardening will also normally have a lot of grey steel surface where the quench scale is popped off.  Underheating it will leave the whole surface black.  Again, as before, this is in my quenchant in my shop.  I have a sword quench tank and the oil (mix of corn oil and canola oil) doesn't pop off the scale as reliably, so don't take it as gospel.  Also, an overheated blade will still pop the scale, so it is an indication that I got the temperature *at least* hot enough.

Do the rest of your blades to this point. 

Now, with shop rags, work to get as much of the oil off as you can.  Really wipe them down.  You don't want burned oil stinking up your kitchen when you temper.  I used to wash them with Dawn detergent, but don't find a real improvement from that, so I quit doing it.

I wrap my hardened steel blades in aluminum foil, loosely, then place them on a cookie sheet.  The idea is that it evens the heat out as it reaches the blades.  This could be wasted effort, but I don't believe it hurts.

Into the oven and temper for an hour.  Then air cool and bake for another hour. 

For 1095, I do 400 degrees for knives,  500 for swords.  For the spring steel I enjoy forging, I use 375 for the knives.  Known 5160 gets 475 for big choppers. 

This is, as I said, my method in my shop.  I like the results for my blades.  Your shop will be different, so only treat this as a suggested starting point, not a gospel.

-Patrick

Check the edge hardness with an old chainsaw file.  It will knock off some scale, but should not be able to bite into the steel itself. 

Offline Don W

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Re: Heat treatment
« Reply #19 on: September 02, 2021, 07:37:19 am »
Buy a chunk of 1084. You'll love it. So much less work than truck springs and so much more predictable. Save the text springs for froes and those kind of projects that are not so heat treat critical
Don

Offline Fox

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Re: Heat treatment
« Reply #20 on: September 06, 2021, 12:25:29 pm »
Thanks so much for typing up your heat treat method mr woolery!
Why must we make simple things so complicated?