O1 Tempering

U

Union Creek

Joined
Feb 3, 2000
Messages
17
I'm new to making knives and have only worked with 1095. Can O1 be tempered the same as 1095 with the use of a magnet?

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Bob G

[This message has been edited by Union Creek (edited 02-03-2000).]
 
yes u can
heat steel till mag doesnt stick,keep it in a tad longer,pull out and quench in oil at 125F.temper at 375 for 2 hours.
I also started puttin the blade edge in wet sand and drawing the spine to a blue color and the edge to a straw color.makes a strong blade and an awesome edge holder!!
biggrin.gif


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That which does not kill you, only makes you stronger
 
I was glad to see O-1 fan say, "heat steel till mag doesnt stick,keep it in a tad longer". I often hear people say to heat until a magnet doesn't stick, then quench. If you are checking frequently with the magnet (as you should), the steel actually begins to go non-magnetic before it gets into the critical range. For instance, on the 10xx series steels, with a critical range of 1450-1500 F., the steel starts to become non-magnetic at around 1335 degrees F., if memory serves me correctly.
 
O-1 is right on the money. I'll have to try the wet sand trick sometime, sounds like it would work well. Be sure and keep a close eye out for the straw color, changes to blue as soon as you turn your head.

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The mass of men lead lives of quiet desperation.
 

excuse me for my ignorance,forgive me because i'm new to thi knifemaking.
what exactly is the prefurred oil to quench knife steel in,or is there different oils for different steels?

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Shane ------------------- If you don't have time to do it right the first time, When do you think you'll have time to fix it!!!
 
rookie,
You can be sure that no one here will think that question is asked in ignorance. It's darn good question and would certainly merit its own topic here. You would probably be amazed at the number of different quench mediums used. The best one is the one that works for you. There are specific quench mediums available, but it seems like most knifemakers come up with their own concoctions. Some use plain old crankcase oil (motor oil), some use vegetable oil, peanut oil, olive oil, etc. Right now I use a combination of crankcase and transmission oil at 150 degrees F.

You will see things like "don't let the oil get above x degrees" but it's not so much the temperature of the oil that's important. Oils of a higher viscosity don't wick away the heat as fast as thinner oils. Heating them up lowers the viscosity and increases the speed at which they pull heat from the steel. When the steel hits critical, the internal stucture is a micro-structure called austenite. In the quench, the steel must be quickly dropped from critical temperature to 400 degrees or so, which where the austenite transforms into martensite. Iron-carbon martensite is the hardest form of steel and is the micro-structure you are trying to achieve in the hardening phase. I'm sorry -- I'm rambling. I've gotta quit drinking so much coffee.
 
thanks, tepering steel sounds really deep!!!! but i need to learn, for my ultimate goal is to fly solo from start to finish , with no outside help!!

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Shane ------------------- If you don't have time to do it right the first time, When do you think you'll have time to fix it!!!
 
Primos,
Did I understand you right?
Would some high-quality synthetic oil then be actually the best alternative?
rgds,
Leif
 
If you are going to use crankcase oil, you might as well use the cheap stuff. The steel doesn't know how much you paid for the oil.

I should clear up one thing that I said in my previous post. I mentioned that it was not so much the temperature of the oil that mattered. I didn't say that exactly right. Cold thick oil won't quench right, but if it's overheated, it may not quench fast enough. It really depends on what you are using. For 30W crankcase oil I have had good results from about 125 degrees - about 150 degrees F. If the oil gets around 180 degrees I usually back off.

A good way to tell if you are hardening properly is to allow the blade to cool after the quench, then rub the blade down near the edge with a file. The file should not cut into the the steel, but rather "skate" across it like a sheet of glass. If the file "bites" into the steel, you definately did'nt achieve maximum martensite. If the blade just laughs at the file, then you've done good. Be aware that fully hardened steel (untempered martensite) is very unstable. It's like a balloon so full of air, it's about to bust. You'll want to move on to the tempering phase as soon as possible.

As far as choosing the quench, there are commercially made quenchants are rated as medium and fast quench. I believe they come with info on proper temperatures.

Good grief, I'm rambling again... Uh, what was the question? (Ha-ha).
 
Thanks to everyone that responded to my question on tempering O1.

I can see I have a lot to learn and to just ask the question and then go ahead and do it.

Thanks,
 
Some oils have a lower flash point then others, so have a tight fitting lid to smother out any flare ups.
 
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