Quenching?

[HOOD]

Ok I like so many others here have started to make a couple of knives here at home (which I accually started early last year....slack I know).
I have read of others using cooking oil and clean motor oil to quench the blade.

So I ask; is quenching with oil better then water and if so why is that?

[jamie]

First of all what type of steel are you playing with?

As far as I know 01 or the 10 series steels can be H/T at home but D2 better send to Hills

Some steels don't like a water quench and will shatter.

Olive oil works well just heat it up a bit before you dip the blade in.
Heat another piece of steel and drop it in the oil before you quench your blade.

Do you have a magnet to check if the blade is at non magnetic ?

Sorry if I haven't answered your ?'s but I'm still a novice when it comes to H/T at home.
Maybe Jindy can shed more light on this.

[jindydiver]

The O in O1 stands for Oil, as in the medium you use to quench it. W1 is also used to make files and you can guess what you quench that in :D . The problem is it isn’t straight water, you have to use a strong brine. What happens when you quench is you are “freezing” the steel in the state it is in while it is at a critical temperature and you have to bring the temperature down fast enough to do that, but too fast and you will have troubles like warps and cracks. I quench in a drum of solidified cooking oil. The hot steel transfers the heat quickly to the oil as it melts it and it works well for me. If you use water you can get a barrier of steam against the steel and it stops the heat getting into the water and the blade will not quench properly. You have all seen water on a really hot BBQ plate and how it turns into a ball and doesn’t vapour away because the steam on the bottom insulates it from the BBQ plate. Same thing happens in the quench.

Motor oil, automatic transmission fluid, cooking oil, all are good quench mediums but some have drawbacks. The motor oil makes a bit of a mess of the blade, and both the motor oil and the AT fluid need to be heated to quite hot or they also can get a vapour lock when you quench.

The quenching works for all the simple steels, things like files (O1 or W1), car springs (5160), bearing cases (52100) and old saw blades (L6), but if you decide to buy some stainless knife steel you need to either have a temperature controlled heat-treating oven or you have to ship your blades to someone like Hills to get it treated.

And for all you guys who want to give it a go, when you dunk the blade in the quench do it edge first and DO NOT shake the blade around. You need to keep the effect of the quench even on both sides and the only way to do this is by "cutting" into the quenching medium with the blade. It also means the edge you want to get hardest is getting lots of contact with fresh oil, not oil already heated by the spine of the blade.
As you get more into it you can start just quenching the edge and leaving the spine out of the quench so it stays softer and much more pliable.

[Tj]

Great info as usual Jindy

There seems to be a growing interest in the subject at the moment can you recommend any sites that go right into steels and the different techniques used to harden them? It would be interesting not only from a knife perspective but also so we can better understand broadheads.

TJ

[jindydiver]

A few of the websites I visit



this one will keep you going for a year or so :D
http://www.knivesby.com/knifemaking.html




http://www.zknives.com/knives/articles/knifesteelfaq.shtml
http://www.agrussell.com/knife_information/steel_guide/index.html
http://www.crucibleservice.com/datasheets/index.cfm
http://www.diamondmetals.com/l6.html
http://ajh-knives.com/metals.html

[Luke]

Wow! :shock:

Thanks for the info and links Jindy :D

[Tj]

this one will keep you going for a year or so :D
http://www.knivesby.com/knifemaking.html


At least, and just as I move into exam time.

Thanks those links are great.

TJ

[Jimmy Alexander]

Now im stuck on this one lol
Thanks Jindy

[HOOD]

Thanks for the info Jindy and the links.

if all that is food for thought then my brain is blouted already.

The steel I'm using are some old files.
One of which has previously been forged into a sort of bolsted/wedge shape which is a perfect platform to start a knife from.

The other steel I'm using is a SS washer of 3mm thick which I'm making into a skinner.

Will start a post tomorrow showing what I have done so far and what I intend for them to turn out like.

Thanks again Jindy