Hello, I have been using the kitchen oven for tempering small to medium sized blades. It has seemed to work passably well, but now I'm interested in getting a set up that is both more reliable and capable of tempering sword length blades. Looking around I see lots of options for heat treating set ups, however, as I am only really interested in working with the lower temperature ranges these seem rather excessive. I was hoping to hear what people are using, get some advice on buying verses building the lower temp equipment I'm after and some tips on material references.
Thanks Guys!
-Noel
Hello Noel,
I have built a heat treat oven and used the parts from these two companies: www.Duralite.com for the heating elements and www.auberins.com for the PID control and other electrical parts. I bought the soft fire bricks locally to save cost on shipping. I have considered building a tempering oven as it would not require as many bricks as the heat treat oven. The fire bricks are the largest costs in building the heat treat oven but I still saved about 50% over a factory built oven and I will put my oven up against a Paragon or Evenheat oven any day of the week.
I enjoy building some of my own tools and equipment and the satisfaction I receive from using them. But if you do not have fabricating experience or the tools to do so, paying someone to do this would be cost prohibitive. So your experience and shop capabilities will reflect greatly on your decision to build any piece or equipment or tools. If I can help you more, let me know.
Anthony Griggs
Noel
I forgot to mention, the heat treat oven will serve as a tempering oven as well. Just do a snap temper at say 325 degrees in the kitchen oven, then after the heat treat oven cools down set your heat treat
oven at your tempering temp. and there you are with a spot on tempering temp. That is the nice thing about the PID control, you can set it at what ever temp you need and it will be spot on once it
stabilizes. Unlike the kitchen oven that can fluctuate 10 to 25 degrees up and down. ---NOTE--- do not cool the heat treat oven down by leaving the door open!!! this puts a lot of stress on the heating
coils, and may or will shorten there life.
Anthony Griggs
Anthony- Thanks for the info. I have been wondering about the heat treating ovens ability to keep a stable temp in the lower ranges. Good advice on not leaving the door ajar to cool, probably saved me some head ache with that one! I certainly prefer the fabrication rout, it always seems to leave me with a better understanding of my tools. I am curious though about your recommendation of the snap temper in the kitchen oven. Whats its purpose?
Noel
It takes 8 to 12 hours for my heat treat oven to cool down enough, before it can be used for tempering. By doing a low temp. snap temper, typically 300-325 degrees for about one hour, you relieve
the stresses in the harden blade to prevent stress cracks that could or might form as you are waiting for your oven to cool down. Why chance it?
I made a rifling head cutter out of O1 tool steel a year or two ago, and after hardening it I received a phone call and was distracted and forget to temper it. About two days later I was able to
get back to the cutter and when I picked it up off the workbench it broke into. Upon closer examination it had hairline cracks running all through it. When heat treating books say temper immediately,
after hardening, this is why. Hope this helps. Let me know if I can help more.
Anthony Griggs
