What to hold quenching oil in and other 01 heat treating questions???

J

J. MacDonald

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Jun 8, 2000
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3,140
So I bought a couple fire bricks today and a propane torch and a hard drive magnet and am hoping to try to heat treat a small knife I've ground out of some 01 stock. I'm going to drill the fire brick as indicated in the How to heat treat 01 thread and build a one brick forge. My question is what to hold the quenching oil in and how much oil do I need. I grabbed a gallon of veggie oil at the supermarket, but it looks like I might need more? Should I just buy a cheap stock pot and put a couple gallons of veggie oil in it? At first I was thinking that I'd just cut the top off of the veggie oil container, but then I figured that if I touched it with the hot steel, I could end up with oil everywhere, and that would suck.

Some guys have mentioned heating the oil. I was thinking that I could put it on my gas grille on low to heat the oil and set up the one brick forge near by on an old washing machine basket.

Once I heat to non magnetic and quench the blade, what's a good temper recipe to draw the 01 back down?

Can I use channel lock pliers to work with the hot blade, or is something else recommended?

They seem like dumb questions, but I don't want to screw this up.

John
 
I use a valve cover for a quench tank. Works fine for me. I heat a piece of metal up until it's bright orange and drop it down in my oil. It gets it up to about 150 degrees, according to my thermometer.
 
I use a coffee can for my oil. Put it on the stove on low-low heat for a bit till it warms up. For long blades I have 2 coffee can epoxyed on top of each other with the bottom cut out of the top can. No leaks yet. A plus to using these you can put the plastic lid on them for storage after the oil cools down.
 
John, all most any fire and heat proof container can be use for HT quench. Mostly it depends on the size of the work. I have a dogfood can of transmission fluid in the shop I use for small blades. Out in the forge proper I have a tank made of 2/3rds of a 100LB Propane tank that holds about 15 gallons. Any metal container in between can work fine, A turkey roaster, a valve cover..I have even seen knives quenched in a trough of oil made of sheet metal sitting in a trench with the ends roughly crimped in. Remember, a small can of oil will get surprisingly hot, surprisingly quick. It is easy to burn you hands, etc.
 
Cascade three large coffee cans, solder them so as make leak proof. Take your wife's crock pot and set the can into the pot. Poor oil into can array. Fill void around can array with water. Using a thermometer to monitor oil temperature cook on high until about 100 F., turn switch to low and continue heating vegi oil until about 125 F. Try to time it so that when blade is ready to quench the oil is about 125 F. Get the blade into quenchant quickly and delibertately. Submerge all of it quickly and immeditely moving the blade back and forth in a cutting motion, NOT side to side. While doing this count to about 7 or 8 seconds. Pull blade. In the mean time your tempering oven has already been preheated to 400 F. After pulling the blade, it should smoke but not flame, allow it to air cool to hand warm (about 125 - 140 F). At which point immediately place in 400 F temper for no less than 1 full hour. Remove and allow to air cool to room temperature. Repeat tempering for a second and final time for no less than 1 full hour. You did it.

Heating the oil on a stove top or open flame is a good way to loose the house.

RL
 
Go to your local Garden Ridge store(yeah, I know. Only women shop there, but I was forced to go one time and decided to make the best of it). Get yourself one of those big stainless stock pots. Use one of those hot plate warmer things to heat up the oil.
 
John,
Cheap pair of long-handled needlenosed pliers will give you better control.

Caution - heating your oil with a block or chunk of heated steel works OK but don't "drop" it in, place it in the oil and you'll avoid possible burns and fire. Use a candy or baking thermometer to check the oil temp and get it between 140 and 160 degrees F for a good quench for O-1.

I'd use an iron base magnet not a rare-earth magnet. The R-E magnet is so strong it will give you fits testing on your way up to critical temp. It will also loose it's magnetic strength on repeated contact with high temp steel. The
I-B magnet will hold up better and be easier to work with. Glue it to a stick and save your fingers some pain.

Coffee can should work fine for a small blade however larger blades do better with more oil/bigger container. Keeps the quench temp from changing to fast in the tank during the quench.

Remember to draw the temper on the blade at about 415 deg F. after cleaning off the oil. Have your oven preheated to this, use an extra oven thermometer to confirm the temp. Let it soak at this temp for about 2 hours and then air cool to room temp before finishing.

Have fun. O-1 is good steel and makes an excellent cutting blade with the correct geometry.

Carl Rex
 
John,

Knifemaker J.P. Holmes showed me what he uses to hold quenching oil. He pick one of these at a local salvage yard for $20. Back in the day soda syrup came in stainless containers and they have a oval opening on them with a tight sealing lid. They have two threaded stems which you can place your thermometer in. It holds 5 gallons of oil very well.

Jeff
 
I do like Danbo, have a turkey baster sitting on an electric hotplate. If I'm in a hurry to heat up the oil I do like Tom and Kit, add a hot billet to bring it up to temp. Doing one knife in a gallon of oil would be okay but that's probably not enough oil if you're doing several - each one will heat the oil a bit. ;) I'd use big pliers rather than the channel locks because the pliers are straight so will be easier to manage the blade. As for a magnet I've had good luck with a small pickup magnet on a telescoping thing the size of a ballpoint pen. Easy to hold and the magnet isn't so strong it's gonna grab your blade the first time you test it. :D So far it's maintained its magnetism for a couple of years.

Listen to Roger about the HT process; very few have done the extensive testing and record keeping he has. Roger knows what he's talking about; he taught me and I know the method works. ;)

The hardest thing for me to learn was how not to overheat the steel. Keep testing with your magnet as you bring it up to temp.
 
At work we use an electric fry pan with a meat thermometer for a quenching tank. Fry pans at a garage sale -- $0.50 to $1.00 :D

Strong magnets are found in throw away speakers -- ask any kid that is into music they seem to wreck speakers like they were free. :mad:

Welcome to the world of knife making.
 
rlinger,
I undertsand everything you said (great details by the way), but I just don't undertand ONE thing. You say to,

"Take your wife's crock pot and set the can into the pot. Poor oil into can array. Fill void around can array with water. Using a thermometer to monitor oil temperature cook on high until about 100 F., turn switch to low and continue heating vegi oil until about 125 F. "

I'm not so sure I understand all this. Why the coffee cans INSIDE the crock pot, and why water in the "array". I assume array means the dead space around the coffe cans?
Just wondering. Thanks bud.
 
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