How many knives do you all heat treat at a time?

S

Shannon Carter

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Mar 26, 2012
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Will be trying my first heat treat this weekend with new oven and I will most likely start off with one piece at a time, but the question came up about how many can be done at a time or what is a safe number/what do most feel comfortable with? I will be using O1 so I will be oil quenching - Parks AAA, thanks to forum advice. I guess my real question is about the process of quenching more than a single blade at a time - how much does the oven cool down between opening the door and removing knives and is that a real issue? Also, I assume I will need to keep the oven running during the time while knives are being removed, although Evenheat recommends turning the oven off before reaching in to remove blades!

Anyway, I hope that question made sense and thanks ahead of time for the help!
--Shannon
 
I would cycle the blades one at a time. I do oil hardening stuff one blade at a time until my quench oil gets to the maximum reccomended temp. For air hardening stuff I do as many as my quench plates allow. This just what works best for me. You may find another method that works better for you. Good luck and have fun.
 
Darrin,

Okay, so for the oil hardening stuff, do you only have one knife in the oven at a time or multiple? I knew I would be quenching one knife at a time and monitoring my oil temperature as I went.

Thanks again,
Shannon
 
I'm curious about this as well, as I'm ordering a kiln in the next couple weeks. I have a ceramic rack coming as well which holds 4 blades, so that was my planned target.. per batch for now.
 
I have an Evenheat as well and I have their fixture. With thinner blades I can sometimes fit eight blades at once, that is two in each of the four sections. My Oven came with a switch that turns the power off to the elements when the door is opened. I am sure your will have the same thing. As far as heat loss, I would see a drop of ten to twenty degrees most times depending on how fast I was. Now I have a 1/4" stainless plate lining the bottom so most time I only lose about five degrees and ten at most. Getting my own oven was a great purchase, but I try not to run the oven unless I have at least four knives.
 
I have done O1 and usually put in as many as the oven will hold, I am pretty quick, I arrange the knives so that I can grab with the thongs, I have not seen much of a temperature drop, I check the temperature to make sure it is at the proper level before grabbing the next blade. I will mess with the quenched blade and not in any hurry to grab the next. The real issue with multiple blades is keeping the quench from over heating, I put ice in a double freezer bag and dip into the quench to cool, this will depend on how many, how big, and how much parks you have.

The other think to check is make sure the blade is straight, you will have a few seconds to straighten after the quench.

The other thing I do is cut some test blanks from the same steel, I will quench and test them first to make sure everything is correct, snap a couple to see the grain, the test pieces will go with the blades into the temper oven so I can see how the performance of the steel will be after temper as well.
 
Big Chris said:
I have an Evenheat as well and I have their fixture. With thinner blades I can sometimes fit eight blades at once, that is two in each of the four sections. My Oven came with a switch that turns the power off to the elements when the door is opened. I am sure your will have the same thing. As far as heat loss, I would see a drop of ten to twenty degrees most times depending on how fast I was. Now I have a 1/4" stainless plate lining the bottom so most time I only lose about five degrees and ten at most. Getting my own oven was a great purchase, but I try not to run the oven unless I have at least four knives.
Click to expand...

I will be using the ceramic rack, too, and I figured I was safe to heat more than one at a time. Sounds like it does cool, but not as quickly as I had imagined. Thanks for the reply.
 
Patrickknives said:
I have done O1 and usually put in as many as the oven will hold, I am pretty quick, I arrange the knives so that I can grab with the thongs, I have not seen much of a temperature drop, I check the temperature to make sure it is at the proper level before grabbing the next blade. I will mess with the quenched blade and not in any hurry to grab the next. The real issue with multiple blades is keeping the quench from over heating, I put ice in a double freezer bag and dip into the quench to cool, this will depend on how many, how big, and how much parks you have.

The other think to check is make sure the blade is straight, you will have a few seconds to straighten after the quench.

The other thing I do is cut some test blanks from the same steel, I will quench and test them first to make sure everything is correct, snap a couple to see the grain, the test pieces will go with the blades into the temper oven so I can see how the performance of the steel will be after temper as well.
Click to expand...

Thanks, I hadn't considered using test blanks, but that is a good idea.
 
I usually do about five at a time when I'm doing it in-house, and more like 20 at a time when I send it out.
 
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