Quenching knives

[50cal.cliff]

I have heard of folks heating the oil for quenching, what is the average best temp for this?

If you use water does it need to be heated?

When quenching a knife blade, which is better oil or water?

Do you quench in a horizontal or vertical position?

What is the proper temp for tempering steel, say like the steel in an old two man saw?

I have one hanging in my shop, and have been looking at it long and hard lately! :hmm: I almost hate to cut it up cause it looks like its in ready to use condition! When I got it I cleaned the steel and oiled. Thats the way it has been sitting for last 10 yrs., but its beginning to talk to me! :youcrazy: It keeps saying sure would make a bunch of good knives! :rotf: :rotf:

 

[Blizzard of '93]

Light oil (ATF) horizontal and plunge it deep. Light oil keeps the blade from warping. Get oil up to 100deg. Draw back to straw color for 10 min.immeditealy ice it down for 2 hrs, and repeat. You won't be dissapointed. Very flexible blade as spring steel.

 

[Twice boom]

I have heard of folks heating the oil for quenching, what is the average best temp for this?

If you use water does it need to be heated?

When quenching a knife blade, which is better oil or water?

Do you quench in a horizontal or vertical position?

What is the proper temp for tempering steel, say like the steel in an old two man saw?

I have one hanging in my shop, and have been looking at it long and hard lately! :hmm: I almost hate to cut it up cause it looks like its in ready to use condition! When I got it I cleaned the steel and oiled. Thats the way it has been sitting for last 10 yrs., but its beginning to talk to me! :youcrazy: It keeps saying sure would make a bunch of good knives! :rotf: :rotf:

Just a bout everybuddy that heat treats their own knives has his own way that works for them. Mine is to break the quenching oil's chill by placing a hot iron in it...The few books I've read on the subject suggested to heat the oil to a bout 120 F.So take your pick either way works well..

The quenching water could be a bucket of rain water unheated. If the stell calls fo water quenching , can be made harder by quenching it in a salt brine. You can make the salt brine by dumping salt in a bucket or what ever container you plan to quench in ,until a raw egg floats. If I want max hardness,I dodn't care what the steel's designation is unless it calls for air hardening. I quench is salt brine,whenther it calls for oil or water....

Whether one quenches horizontal or vertical might depend of the type and the shape of the blade.To prevent warping..

The saw blade you made refference to, might be a good candidate for the right kind of blade but not for all blades due to its thickness..
I'm told but have no way to prove it that saw blades that where used by hand were tempred to a bout 47 RC hardness.I like my knives in the mid fifty range a digree over or above and not near or above sixty Rockwell C hardness..

If you gonna make a knife out of the two man saw ,1450-1500 f will be just about right. use a magnet to quench when the magnet quites sticking to the red hot steel......Others will tell you to soak the heat to the blade for a minute or two, but I have not found that I can tell the difference in the finished product...

Tempering the blade after the hardening is something you didn't ask about and if you gonna do knives you have to learn the heat color or temepering colors and what hardness they represent...

Get busy ,start the chopping of that two man saw,it has out lived it's usefulness....
Have fun and ejoy the experience.......

 

[50cal.cliff]

Thanks guys! Alot of good info there Twice Boom! :bow: I know what yur saying about the two man saw. I ain't planning on using it, even if I could find another fool to put on the other end! :rotf: :rotf:
Why rainwater, for purity?
If add salt to my rainwater it wouldn't be pure any more! :grin:
You said Twice Boom that the saw blade would be a candidate for the right kind of knife due the thickness! I just went and checked my dial calipers say, it's approx. .014 on the teeth side,and approx. .009 on back side.
So what eaxactly are talking about, "the right kind of knife"?
I am thinking my next project is going to be a Bowie! Are we talking too thin for something like that?
Got any good sources for a refrence to the colors when tempering or tempering in general? :yakyak: :yakyak: :grin:

 

[crockett]

How NW are you in Florida? Wick is in central Florida and a pro. I have made a lot of knifes with the stock removal system but use air quenchable steel that gets sent to Texas Knifemakers to heat treat. They dont treat oil or water quecnable steel.
My own efforts at quenching haven't been that great and if you get a warped blade its a lot of trouble straightening it out. Most folks think the warp is from uneven bevels but steel can develop a memory and you have to normalize it, etc to help insure no warp. i had a gut hook beveled on one side that warped and a thin butcher knife blade that warped and some 6" folding blades that warped. Thin steel 3/32 or less is more of a problem however if you straight a truck spring, beat out a blade and heat treat, the warp may come back. If Wick reads this he'll be able to give you a lot more help, he may be on the member list.

 

[50cal.cliff]

I am so far N.W. in Florida that if I go North or West I can be in[url] Ala.in[/url] about 30-40 min..
Dang, you make warpage sound real scarry! I have talked to Wick on the forum. Don't know him, but didn't take long to figue out he knew what he was talking about!!!!!!!!
I usually do these things on my own trial and errors. Over the years I have learned that can be an expensive process! I thought since we had so much talent here on this forum, I learn from a few others mistakes/knowledge. It don't hurt near as bad that way! :rotf: :rotf:
I tried one of those knife forums, too much :bull: and not enough information! I figure at my age I got to cut the learning curve down all I can! :wink: :grin: :rotf: :rotf:

 

[Twice boom]

Thanks guys! Alot of good info there Twice Boom! :bow: I know what yur saying about the two man saw. I ain't planning on using it, even if I could find another fool to put on the other end! :rotf: :rotf:
Why rainwater, for purity?
If add salt to my rainwater it wouldn't be pure any more! :grin:
You said Twice Boom that the saw blade would be a candidate for the right kind of knife due the thickness! I just went and checked my dial calipers say, it's approx. .014 on the teeth side,and approx. .009 on back side.
So what eaxactly are talking about, "the right kind of knife"?
I am thinking my next project is going to be a Bowie! Are we talking too thin for something like that?
Got any good sources for a refrence to the colors when tempering or tempering in general? :yakyak: :yakyak: :grin:

Rain water is soft water and that's what I use out of habit. Any kind of water is okay and i'm sure I've used water straight out of the garden hose..

I don't know what 014 0r even 009 is in thickness .But I imagine its a lot thinner than an 1/8" . That's why think you have but few choices .One is for a very short knife 2" or less,and the other would be a fish fillet knife. Back when I used to live in Springfield Oregon there was a shop that made up band saws blades from Sanvik steel for the lumber mills. I had permission to pick out what I wanted from the dumspter . I made some great 2 -2 1/4 " gut hook skinners. I would qhench the blade in salt brine and temper to straw color. Normally I like to temper to a blue or the beginning of a purple. With the blade of that little skinner, so small, and not a chance of flexing I felt I could afford to leave little more brittleness in the blade and not have problems...
So your two man saw will make some fine short blades for skinning ,but its not thick enough for a Bowie,which If I were to make a Bowie of any heft I would want to make it out of 1/4" starting out.....

Hammer heads chisels for cutting metal, temper to dark bronze or just the beginning of faint of blue. Knives I like Blue . Wood Chisels bluish /purple.. Plaining Irons, same..

And don't forget if you see a chocolate color on knife blade ,you've gone too far and I would start over again after i annealed the blade..

Sorry for the long winded rant. Hope you find something useful,nonetheless...
TB.

 

[LRB]

Water queching is always risky, salt, or otherwise. Only a few steels are formulated for it, and with steel as thin as a knife, even some of those will crack. First thing, forget the magnet trick. When steel reaches non-magnetic, it only just starting to go into solution. Even the simple steels need to be around 1500o, which in dim light is red-orange, and pretty bright.
Simply being hard is not enough, if one is looking for the best he can get from the steel. The iron, and carbon, or in the case of alloyed steel, the alloys, need to be in a homogenous solution when quenched, and that is dependent on heat, and time. One can have a blade that a file won't touch, and still not have an ideal result. There can be pockets of pearlite, which is iron and carbon that are layered rather than mixed, surrounding pockets of martinsite which is iron, and carbon in solution, and very hard. You have microscopic hard , and soft spots. Not the best situation, but a file still will not cut the blade. In other words, the file test is a false/positive test, although necessary, to see if you did anything at all. The simple steels only require a couple of minutes of soak time, but at a much higher temp than non-magnetic. 01 steel is an alloy containing tungsten, chrome, and vanadium. It requires upwards of a twenty minute soak at 1500o, and de-carb protection, if one wants the best he can get. That said however, 01 will usually out perform the others, even with a less than perfect HT.

 

[Twice boom]

Wick may have a better idea. But if you heated and straigtend the truck spring first, heated again and covered it in a bucket of lime or wood ashes to anneal over night, it will not spring back on you after the knife is made...IMO.....

 

[Twice boom]

My opinion is when in doubt of the steel you have quench in salt brine..
The old time smiths from days gone bye most always quenched in salt brine. And the steel they had back then does not compare to the modern mill steels we have to day..

If the steel is hard enough to harden to where the file wont touch it ,from there it's up to God and the tempering you put on the steel if the knife will work as you invisioned it.......

The magnet trick has served me well over the years. The steel gets quite a bit brighter than a dull red before the magnet stops sticking ,in fact I believe its around 1450 f..
Alloy metal is another animal all together and in order to do proper hardening or tempering you need atmosphere free ovens that can reach 2250-2350 f nd keep the balde at that temp for an hour or two..
But for a guy that wants to do a knife out of 01-W1 and or a truck spring the magnet trick will serve him better than the naked eye.IMO...

 

[LRB]

Different steels go non-magnetic at different temps. Most will be in the range of 1400o, to a bit over. 01, and 5160, are alloy steels. Both contain a relatively high amount of chrome, and require a soak in the range of 1475o to 1525o, in order to get a good solution. The better the solution, the better the performance, and the better the strength at a given hardness. An atmoshere free oven is not required. There are easy to use coatings for the steel which prevent de-carb and scaling, and can even be used in a forge.

 

[Twice boom]

True. I was reffering to the 440-C - 154-cm type high carbon alloys, the O designates Oil quench...

My opinion is that 50-75 degree differnce don't amount to much. My refferences tell me for 1095 high carbon steel to bring it to 1450-1475 and to quench iimidiately. For 01 anything less that 1/4" 1450-1475 f heat evenly (as you should with alltype of steels) and quench in 125 degree oil.. So as you can see we are attempting to waltz on the head of a pin with so little differnce s between us......
More importan is how you treat the steel during the forging process of the knife, whether the blade will fail or not rather than one hundred degrees,more or less before you quench.. And if I wanted to (I always do) aline the steels molecules, I do that by packing them when I'm done with the forging of the blade.. :v

TB.

 

[Twice boom]

Yes, but the other side of the story is if we are attempting to harden alloy (high chromium,nickle,etc.) like 440-C -154-CM and the like . They have to soak an hour or two at 2250-2350 degrees per inch in thickness...While it can be done in the forge ,still not a good idea to attempt it for a fellow that is particular a bout 75-100 degrees . :rotf: and not to mention that you will have no way of knowing at what tempreture most forges are running at ..
Best send blades from those metals to a pro.. :wink: :v

TB.

 

[LRB]

50o to 75o can make a vast difference in the quailty of your steel, especially if you are on the low side. That is quite a spread. As far as packing the steel, this is a physical impossibility. Steel does not compress, and anything done to it before heat treat is nullified at the quench temperature. Grain structure is controlled only by heat. Nothing else. Yes, so called packing will form smaller grains, but when you heat the steel above non-magnetic, they grow right back where they were. The steps in normalizing will produce finer grain, if you do not have it already, such as in the case of 01, which is fully spheroid anealled when you get it. Normalizing will not improve the grain structure in this case, unless you forged it. Then it is a required step. Forgeing, or packing, does absolutely nothing to improve grain size, or structure, and steel is not a molecular structure, it is made up of crystals. When you "pack" this grain stucture, you are breaking up the grain units and forming smaller units of irregular size. When the steel is heated, the larger grains gobble up the smaller, and put you right back where you started. The mutiple heats during this packing process is the effective denominater, not the acuall packing.

 

[Twice boom]

Like I said , we are dancing the waltz on the head of a pin. :hatsoff: I'm going to :bow: out,as I see no point in discussing the mere 50-75 digrees ,when there are so many important things that come in to play prior to the quenching of a knife blade, if forging is the process used.... Later, :hatsoff:
TB.

 

[50cal.cliff]

To all of you thanks! I now everyone has different opinions. The reason I initally asked this question was becasue of a post on another forum. Guess I could have asked it over there but, I like you guys better!! :rotf: :rotf:
The guy was talking about breaking like 8 knives in a row water quenching! I didn't want that to happpen to me.
I feel as naked on this subject, as a newborn baby! :shocked2: So I am trying to gain the benefit of evryones knowledge. I know there is things I am just going to have to learn on my own. In fact I usually learn better hands on. Wish there was some blacksmith courses being taught nearby but can't find anything. I suppose some metallurgy classes wouldn't hurt either. Hows that ole saying go, "can't teach an old dog new tricks"! :rotf: :rotf: