Quenching oil

Steve Randall

Steve Randall

Well-Known Member
I was wondering if anyone has used auto transmission fluid for quenching. any problem to fast to slow ? I use mostly 5160 some 1084,1095 planing on some 52100 thanks ...steve
 
The "quench speed" of ATF is not a property they're trying to control (obviously), so there is nothing in there to reduce vapor jackets - so compared to an industrial quench oil it will be a little slow and uneven during the start of the quench, and a bit faster than ideal towards the end of the quench.

But, that said - ATF is said to be relatively fast (I have no real way of knowing) and will probably work okay for all those listed with perhaps the exception of 1095 in thicker sections. You'll want to agitate well which will help some with the lack of vapor jacket control. Warming it up to 140 will improve its performance by reducing the viscosity.

I personally wouldn't sell a knife quenched in ATF, but it will probably be okay if you're just doing this for grins.

Beware the fumes and fire hazard. Do this outside if you can and have a lid around etc.
 
thanks for the info. what is the best oil to use ? the other thred was talking about mineral oil I guess I could try that . I have used veg oil and it was ok just looking for somthing a little better...steve
 
Ksran2 said:
thanks for the info. what is the best oil to use ? the other thred was talking about mineral oil I guess I could try that . I have used veg oil and it was ok just looking for somthing a little better...steve
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The best oil is an oil designed for quenching. 5 gallons of quench oil is about 60 bucks from McMaster. 5 gallons is plenty of oil. The "11 second oil" is intended for use on 1080 and similar steel.
 
thanks for the info I will check them out. I know a lot use parks 50 and AAA but I have not found where to get some and was trying to find somthing local ...steve
 
Shankmaker said:
I looked up the oil your talking about. http://www.mcmaster.com/#quenching-oil/=41rifv

What is meant by 11 sec quench time and 28 sec quench time?
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That is a measure of the time it takes some standard shape to go from one temperature to another in the oil. Parks 50 is almost as fast as water - I believe it is a 9 second oil. The 11 second oil is said to work with 1095, but it is borderline, forming pearlite in thick sections like the spine. But it should be fine for most fast quench steels and too fast for things like O1 and 154CM -those need the 28 second oil
 
Nathan The Machinist said:
That is a measure of the time it takes some standard shape to go from one temperature to another in the oil. Parks 50 is almost as fast as water - I believe it is a 9 second oil. The 11 second oil is said to work with 1095, but it is borderline, forming pearlite in thick sections like the spine. But it should be fine for most fast quench steels and too fast for things like O1 and 154CM -those need the 28 second oil
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Parks may be as fast as 7 seconds, Nathan. I really like it because its operating temp range is basically room temp (70-120F) in Florida for at least 11 months out of the year. The "medium fast" Houghton oil, which is repackaged and sold as Tough Quench by Brownells is like an 11 second oil at 150F and a 13 second oil at 100 or 200F. it works great on stuff like Admiral 1080 and would probably work just fine on stuff like Aldo 1084. For 1095, I wouldn't mess with it unless I had some #50.
 
Ive heard good things about the Parks 50.

I know Ed Caffrey uses heated Vet Grade Mineral Oil. Would the mineral oil you buy in a pharmacy be the equivalent of Vet Grade??

The reason I ask is there is a pharmacy going out of business here that I can buy it by the quart for $0.85. What temp should the oil be kept at for quenching?

Thanks in advance.

God Bless
Mike
 
For whatever it's worth, Joe Szilaski uses Ford (Motorcraft) ATF for his 10xx series steel, at 140 F. He says that it's the next best thing to commercial quenching oil.
I've used it for quenching 1084 with great success, but for 1095, go with Parks 50.
All I use now is Parks 50 and AAA.
 
Great topic here ! And a sensible discussion on the topic, imagine that.

I do have a question though.

Like Nathan mentioned McMaster Carr 11 second has been said to be "fine" for 1095 but we do know that its borderline. I'm taking this to mean that this oil will harden the steel to the makers satisfaction but do they really know what they ended up with in the shallow hardened part of the blade ?

Purely guessing here but I'm assuming they could have a mix of martinsite and pearlite in the hardened part of the blade ?

I have read that agitation has a great effect on the speed of the quench due to collapsing the vapor jacket.

My question is this. I was thinking about building a quench tank that would hold all 5 gallons of oil and use a sump pump to pull oil from the bottom of the tank and shoot a jet of fresh oil across the top of the tank (maybe an inch under the surface).

I'm thinking this would speed the initial quench up pretty close to Parks 50 but still be gentler than brine or plain water.

Any thoughts.

I really want to avoid using Parks due to cost an availability factors so I think the 11 second McMaster oil is the way to go.

Thanks- Josh
 
If anybody wants to try something pretty crazy, I heard of one guy using warmed-up common DOT-3 brake fluid for 1095. He said it was FAST!
 
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Steve Randall said:
I was wondering if anyone has used auto transmission fluid for quenching. any problem to fast to slow ? I use mostly 5160 some 1084,1095 planing on some 52100 thanks ...steve
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Steve,
Please just buy some quenching oil, the transmission oil will work, but good quenching oil will only be a bit more expensive.
These are the major problems with transmission fluid.
#1 it was not designed for quenching.
#2 it has a very low flash point, and it burns very vigiorously and once started it will just keep burning.
#3 It is fast enough for 1095, but only for sections less than 3/16"
#4 see #1


The subject of heat treating is one of my biggest peeves.
There is a way to do it correctly for each steel, this is not a matter of opinion; it is a fact. Heat treating is also the most important step of knifemaking that is easy to get right. Follow the directions and you will get the same result every time.
Except for water quenching there is no historical or romantic reason for heat treating in any other than the proper way.
 
I did buy the 11 sec oil from Mcmaster and have used it on several blades so far seems to work just fine. I am using 5160 I do have some 52100 and some 1084 I assume the Mcmaster oil will work for the 1084 but not sure about the 52100? thanks for all the info....steve
 
I am going to make some test knives and us the McMaster oil and see how much better it is . We did the same thing at the ABS school with our blade.So I was going to use the same test ,cut rope ,chop 2x4's and then bend 90 deg. I just haven't don it yet. The edge seems to hold up well on the one that I have made and quench. steve
 
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