hardening steel

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monkey boy

Full Member
Jan 13, 2009
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london
i am at a stage of hardening my knife that i am making, but i have a question about the oil i am using.

i bought some engine oil from wilkensons, on the lable it says MULTIGRADE MINERAL BASED FORMULAR 20W 50 MOTOR OIL,

is this stuff going to be ok to use to harden my knife?
the oil is brand new, is that going to be a problem or does it have to be old oil?

any help will be grateful

monkey boy
 
If you watch Greenpete's youtube video...
Number 3 of 4 IIRC it shows the heating & quenching of a blade in old engine oil (so what type of oil is immaterial) but it flares up for a good few seconds, requiring thick gloves, covered arms and some nerve to hold onto it.

Either on Youtube listed under his name (Greenpete) or on his webiste of the same name.

ATB

Ogri the trog
 
you will get flare up, but don't panic! the flames are quite cool (compared ot the metal that you have plunged in the oil), so as long as you keep your hands and forearms covered and your head out of the line of fire, then you'll not get burnt. I seen a few people panic and pull back waving a hot blade dripping with fire all over the place!

Also, it will only flame up when there is something hot at the surface where the oxygen can get to it. So if the tank is deep enough to submerge your knife and the hot part of your tongs then go straight in and you don't get the fire ;)

oh yeah, don't breath the fumes in they ain't good for you! next time try peanut oil, it's much less nasty all round ;)
 
perfect thanx alot everyone, im gonna do it this weekend, then get the handle on, and my first knife will be finished,
dont worry there will be pics ;)
 
i am at a stage of hardening my knife that i am making, but i have a question about the oil i am using.

i bought some engine oil from wilkensons, on the lable it says MULTIGRADE MINERAL BASED FORMULAR 20W 50 MOTOR OIL,

is this stuff going to be ok to use to harden my knife?
the oil is brand new, is that going to be a problem or does it have to be old oil?

any help will be grateful

monkey boy

Its worth watching this YouTube video from a master knifemaker that uses olive oil
http://www.youtube.com/watch?v=srF3xOmnMt0
also have a look a the principles of quenching (the stages the oil goes through which explains why you should heat the oil first)
http://www.bladeforums.com/forums/showthread.php?t=639019
 
I have never done this but was watching an American DVD which showed one of their well known knifemakers doing it, a guy called Tai Goo, who said that it helps if you quench the blade so that it is aligned with the tip of the knife point towards magnetic north, as it helps the crystals in the steel to line up correctly. Thought I would mention it.
 
John Fenna said:
When the moon is waxing?

Are yea mad, man? Never when waxing.. unless you turn the point to the south, or if you are in the southern hemisphere, then north and waxing... Waning is what your looking for here..
 
Actually there is "Science" in using the waxing moon - strong growth time...or would that lead to large crystaline growth in the steel...?
 

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