Heat Treating Multiple Blades at once??

jll346

jll346

Knifemaker / Craftsman / Service Provider
Joined
May 29, 2006
Messages
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I have always used an outside source for my heat treating. For convenience and other reasons I have finally purchased my own HT Oven. My question is on doing multiple blades at once. When quenching a blade it will obviously raise the temp of the oil. The second will raise it more and so on. SO MY QUESTION IS....When doing 3-4 blades, will the oil get too warm after a few to be working correctly?? Thanks.....

-Jim
 
hello I am just giving you a common sense response, as I have never heat treated a blade ever (my disclaimer). If you have a larger volume of oil your oil should not over heat with 4 or 5 blades,now if you you use a quart you may get in trouble. hope this helps but I am sure you will get good info here
 
How big is your quench tank? I notice it rise on mine a bit but I have a 3.5 gallon tank and can do several before it gets to be an issue.
 
Burton said:
How big is your quench tank? I notice it rise on mine a bit but I have a 3.5 gallon tank and can do several before it gets to be an issue.
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I had planned on using one of those large electric roasters as it would be easy to preheat. I would think it will hold 3gal+/-??
 
I use roasters as well, they are nice to preheat the oil in as well as store it. I think mine are 3.5 gallons.

I bet you will be fine, just use a thermometer and be sure to circulate your oil to get an accurate reading.

I recently heat treated a batch of huge choppers. Most were .36" thick and one is about 2 feet long and 3" tall at 1/4" thick. They were at full thickness and after the two largest blades my oil was already too hot! Luckily it was 5160 so I quickly heated up my other oil and quenched the rest in it. I really doubt most people will ever deal with anything this extreme, size wise at least.

On the other hand I hardened 15 - 1/8" thick 7.5" long blades in my oil and it was just fine. I may have thrown a cold piece of angle iron in my tank about halfways through, I really don't remember.

To answer your question, no you probably don't have to worry.
 
Thank you Dan. At what temp is the oil Too hot? I will have a thermometer to watch.
 
Sorry to resurrect an almost 10 year old post, but I've been searching everywhere for this answer. I have been looking through this forum and gotten a lot of great information through from you guys, thanks for that. Anyhow I registered to try an find a conclusion to this. I often quench multiple blades in a row to for efficacy, and at what point is the oil too hot to quench? I'll be using a Parks AAA and quenching 1095 and 5160. Thanks in advance
 
ZiceUnit said:
Sorry to resurrect an almost 10 year old post, but I've been searching everywhere for this answer. I have been looking through this forum and gotten a lot of great information through from you guys, thanks for that. Anyhow I registered to try an find a conclusion to this. I often quench multiple blades in a row to for efficacy, and at what point is the oil too hot to quench? I'll be using a Parks AAA and quenching 1095 and 5160. Thanks in advance
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Welcome to the forum. You should probably start a new threads instead of resurrecting an old one. The data sheet for AAA from Maxim Oil says
130 – 160°F for an open bath. I'm not sure if AAA is the right oil for 1095, I always thought it needed the faster oil, but have never used 1095 myself.
 
Thank you! In my research parks 50 is the most well suited for 1095. That being said I'm still building my knife making setup and chose AAA for it's versatility with as I have been using many different metals. Until I get more room to grow it and can have options. I started with vegetable oil and have had mixed results, but I'm sure there's a point of diminishing return when any oil gets a couple hundred degrees after multiple quenches, just curious where that line is for most people.
 
IIRC, the data sheet for Parks 50 says it's good from ambient temp up to 120F.
I'll suggest doing a bit more research and reading on the topic, focusing on scientific studies opposed to random people's experience/techniques. It's common on the web (especially blacksmithing sites) to read that you have to pre-heat the quench oil, but this is only important if you are using canola or veggie oil, and not an oil made specifically for quenching.
One of the best sites for info on heat treating knives these days is: https://knifesteelnerds.com/ and if you are going to make more than a few knives, especially if you are going to use different steels, get a copy Dr Larrin Thomas' book Knife Engineering: Steel Heat Treating and Geometry.
 
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I actually read their article on quench oils last weekend and through that realized I was doing less than my best by using my veggie oil setup. I started looking into parks oils and the site I ordered from is where I collected the rest of the information about 50 and AAA. Thank you I'll look into that book.
 
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