Home heat treat oven

[Leftieshot]

The knives I've started making need to be heat treated to 1750F.  The material is A-2. Does anybody have some ideas on a homemade heat treat oven?  Doing it at work sometimes is a hassle.

[Leftieshot]

Oh yeah, one other thing.  How do you post pics?  I'm having trouble doing that.  I can't show my blades.

[skullworks]

I copy the message board info out of Photobucket and paste it in the body of the post.

[Jeremy]

An oven? no, but you could just build yourself a small forge and go from there.  You won't be able to reliably preheat the steel at the lower temp and soak it for very long at the higher temp, but for a knife I don't really think that is needed anyway.  

You'll have to gauge the temp by color as well, but if you pay attention at work to the color of the steel at that temp you shouldn't have too much of a problem.

Not as controlled as a digital heat treat oven, but a he** of a lot cheaper!

[Lin Rhea]

Leftieshot,
              Forgive me if I'm misunderstanding you, but I think you may have the critical Temp and the draw back temp confused. 1750F sounds more like the critical temp. Since A-2 is an air hardening steel, you just need to air cool it   (no actual quench) after it reaches critical temp. Then temper (or draw it back)it at a much lower temperature in an oven or by heating the spine of the blade till the color is right.
      I just looked at the recommended drawing temp for A-2 and it is rather high, about 800-850 degrees. I have a heat treat oven, but if I did'nt, I would heat a bar of steel red and lay the spine of the blade on the hot bar, edge up,  with the blade tip hanging out and off of the bar and watch the colors crawl up toward the blade's cutting edge. When the color is right, take it off the hot bar and stop the draw back by placing it in water for a few seconds. Test the edge. If it's too brittle, just do it again, letting the color crawl a little higher. Am I making sense?                Lin

[Bucksnort101]

Here is a link to a home made gas forge I had considered building at one time.

 http://www.zoellerforge.com/simplegasforge.html

[OconeeDan]

http://www.britishblades.com/home/articles.php?action=show&showarticle=31

[Leftieshot]

Thank you for your help on the home made oven.
Lin, your method makes sense but I'm not sure where the misunderstanding was cause I didn't mention a drawing temp of 800F..  Hopefully my blades turn out ok.

[robtattoo]

I think the confusion has come from your terminology Leftie. You asked about "Heat treating" at 1750F in an "Oven" when I think you meant you need to heat your blade to 1750F to reach critical before the quench & you need a forge, not an oven. This is the quenching stage, not really the heat treat stage (which normally is referred to as Drawing or Tempering)
I took it exactly the same as Lin to be honest.

[Leftieshot]

In my trade (die maker) I have never heard it refered to as a forge.  Sorry for the confusion.

[Lin Rhea]

Leftieshot,
           No problem. The main thing is that we might be able to help if you need it. That's why I'm here, to learn and maybe help a little. By the way, from what I've seen, you picked a good steel.
                                      Lin

[Jeremy]

You can buy a digitally controlled heat treating oven for $850 for Jantz, but the heating elements for those ovens only run about $30.  If you can rig up a temperature controller...

I've been to the shop of a few guys who the ovens rather than a forge.  All of them just do stock reduction knives and work mostly in stainless.  That's where the ovens really come in handy b/c they can reliably get up to the high temps needed.  There's also a heck of a lot less scale using the ovens rather than a forge.

A2 is a good steel.  I really like the plane blade I have out of it.  Tough as nails!

[Leftieshot]

What hardness should my blades be 56 or closer to 60?  I'm worried that they are going to curl up like a potato chip.  I plan on placing them on the spine when in the forge or oven and hanging them vertically when they are pulled out and cooling off.

Yes, A-2 is one of my favorite steels to work with at my job.  Hopefully the blades are jsut as easy to work.  It better be, I just got a 6ft long flat bar stock for these knives.

[Lin Rhea]

Leftieshot,
             Here is a quick reference to take a look at. Notice the color chart near the bottom of the page.  
   Also notice the range of carbon in steels that knives are commonly made from. They set .50% as a minimum. In another thread I mentioned .40% as a minimum. It's because I know some have made some servicable blades from this lower carbon content even though the Rockwell is going to be low. This is not so low when you consider that RR spikes are considerably lower  (less than .30%)in carbon and some folks like them. This all depends on the final Rockwell you want. I like for all of my blades to be .60% or higher.
  web page  
                                           Lin

[Leftieshot]

Thats a nice site.  thank you.