Quench Oil

[Drache]

I have just finished grinding out my first three knifes, and I am getting ready to heat treat them. All the information I have read indicates that I need to quench the knifes in heated oil, but I have been unable to find a recomended type of oil.

Should I just go and buy the cheapest oil I can find (motor oil) or are different types of oil better for quenching than others. The knifes I have made so far are O1, and I will probably try 1095 in the future.

I am interested in finding out what kind of oil you guys use. I dont know of any local places to get oils designed for quenching (like parks #50) but I can get motor oil (natural and synthetic and in various weights), animal based oil (lard), mineral oil, transmission oil, brake fluid, vegetable based oils, and pretty much anything else you can get at walmart, VIP, and other chain stores.

Thank you for your help, I look forward to finishing my first knifes.
-Jason

[Ray Rogers]

In general, almost any oil will work. Some oils are faster than others and that means that not all oils will work well with all steels. I used hydraulic fluid on O! for many years with great results. Used motor oil is also pretty good as are most of the oils you listed. Just watch the flash point on the oil, a little fire is to be expected but a small explosion is not helpful at all!

Bottom line, try whatever you have and test the blades. For O1 you shouldn't have any trouble with hydraulic, automotive, or transmission oils among others....

[DiamondG Knives]

From my experiance, the lighter the oil, the faster the quench, and the hardr the blade. BUT, the faster the quench, the more stress on the blade.

I have used olive oil very successfully. SOme folks use a specific kind of quenching fluid, I know Brownells sells it. But it isnt cheap!

Starting out, Id stay with a medium to light vegitable oil. Peanut oil, oilve oil, mineral oil (buy in bulk at vet supply), Tranny fluid. I try to stay away from petrol products cause of the smoke.

Just be prepaired for a fire. Use a metal container (for one or two blades, those mud tubs for sheet rock work will do and they are cheap! .50 cal, or 20mm ammo cans work too and have a lid!

As Ray stated, flare up and flash is expected, but be ready incase your oil ignites, no big deal if you are prepared, kinda scary if your not!

Most will agree that the oil shoul be between 120 - 130 deg use a candy thermometer (walmart) if the oil is cold, heat a piece of scrap and dunk it into your oil.

Hope this helps!

Keep asking questions, thats why this forum is here!!!

God Bless and Good Luck
Mike

[bullsi1911]

I use peanut oil because of the non-objectionable smell if I temper in the kitchen oven

[Jacktheknife]

Hey Drache,

I just hardened and tempered 26 knives made from 1095, and was assisted by a real masterbladesmith who's shop is right down the road. This is responce to the same question I asked him a few weeks ago:


{lets see... copy .paste...}


Jack,
I'm off doing shows on the weekends, but I'll be in the shop tuesday through thursday of this week. Forget those guys, get the old oil you drained out of your engine, dump in 1/2 a quart of automatic transmission fluid for every 5 quarts of used oil, and quench in the oil mixture at room temperature. I've been doing exactly that for about 25 years and it always worked just fine.

1095 is a dual-quench steel (water or oil) which means it stands up to water quenching just fine, so your parameters when you oil quench are pretty broad. Just stick it in the oil mixture and move it around until the oil stops boiling and smoking.

Set the blade aside until they are cool to the touch, then wash them thoroughly using Ajax or Dawn dishwashing liquid and a scrub brush. Put them in the oven for 1 hour at 350-400F and then quench them again in water. Clean them up using your belt grinder and polishing equipment.

Don't let the "armchair experts" get you rattled; it really isn't that hard to do this and 1095 is fairly forgiving as steels go. If you overheat a little bit it really won't matter as you are making short blades anyhow. Overheating promotes grain growth which reduces flexibility, but if you're not making swords it just ain't that big a deal. We all want to get things right, so watch your temps closely but don't underheat trying to avoid overheating, remember that the knife has to go from the forge to the quench and it will cool down as it goes.

As for destroying a knife just to see how well you did, that's bull####. If a blade is too soft, that doesn't mean the rest of them are and same thing for a blade that's too hard. The only time you need to do destructive testing is when you are making a new and unusual design or if you just didn't bother to check your temps when you heat treat.

Jack, you make good knives. So go out ot your shop and do what you've been doing.


That was a copy of the email , {&}
{One of the best complements I have ever had too ! }



J. Knife

[AUBE]

i use water for most of my high carbon knives. 1095, 1080, O1, etc. as long as i have no deep scratches, the edge ground the right thickness and dont overheat the knife(which stresses it more when you quench and can cause cracking) then i dont have problems with cracking. i had to start using water quenching because my old shop was a basement shop and oil fumes werent acceptable. im so used to using water now that i rarely use oil(i go with peanut) and when i do its usually on a clay backed knife, which is more prone to cracking during quench.

i dont even preheat my quench medium...it stays about 65ish degrees in my shop and i quench at that temp with no problems. not recommended but it works for me.

i think most of the problems people have with quenching is uneven grinds, too coarse of a finish, edge ground too thin, temperature too high/uneven when quenching. get those downpat and its easy.

As for destroying a knife just to see how well you did, that's bull####. If a blade is too soft, that doesn't mean the rest of them are and same thing for a blade that's too hard. The only time you need to do destructive testing is when you are making a new and unusual design or if you just didn't bother to check your temps when you heat treat.

i feel its a good idea to test to destruction when you are first learning a heat treating method. just because something works for someone else doesnt mean it will for you. for example that gentleman said he tempers at 350-400 for 1 hour. with my methodology on 1095 that would be too brittle of a blade. i need to temper at closer to 450 for at least one cycle of 2hours...but i always do 2 cycles. steel is cheap. its well worth it to grind a junk blade out to test. just the boost in your confidence level is worth the few dollars/time.

[Drache]

Thank you for your suggestions. I will probably be going to the store tomorrow. Unfortunately I wont be able to heat treat them for a week or so. I will post pictures when I am finally done.


-Jason

[B.Finnigan]

Remember that motor oil is just mineral oil with some detergent additives. When you compare the cost of straight mineral oil with motor oil there is a big diference for almost the same thing.

[NJStricker]

Do you know anyone with a turkey fryer who needs to change out their peanut oil?

[HellForged]

You can get 5 gallons of quench oil from mcmaster-carr for around 50 dollars. Regular oil will work but it isn't as good as quench oil.. otherwise they wouldn't spend money designing and making a specific quench oil. The standard will work fine for any oil quenching steel.(O1, 5160) and the high speed will work fine for water quenching steels (1095, W1). Hope this helps.

~Matthew

[photoman509]

I am also a newb and was wondering if any of you have used bar oil for chainsaws. I just made my firs two knives and built a homemade forge which I am going to use to harden them tonight, the only oil I have lying around other than vegtable oil is bar oil. Thanks in advance : )

[Ray Rogers]

Chainsaw bar oil is much too thick for quenching. Hydraulic fluid and ATF are often used, as are mineral oil and vegetable oil. Used motor oil is at the bottom of the list.....

[photoman509]

ok cool well vegtable oil it is, thanks I'm glad I asked : )