First knife...quick quenching question *rivet hole drilling question added in post #3
I'm in the process of making my first blade from an old saw blade. I have read up on the knife making process and decided to start my first knife today. Right now I'm in the shaping process. My question has to do with quenching. I have a gallon jug of old motor oil, gear oil, and transmission fluid mixed together. Would it be okay to use this mix or is one of the fluids listed really flammable? I know plain motor oil is going to flame up at first but I am unsure about the gear oil and transmission fluid. Will using this mixture have ill effects on my blade or my well being?
Use canola oil and don't worry about it.
Does the canola oil need to be heated up prior to quenching or is it fine at room temp?
Also, can somebody recommend an easy way of drilling the holes in the tang for the rivets? I've tried center punching them and drilling but the punch does not even leave a dip for the drill bit to sit in. I need to get the holes done before I can move any further and go on to shaping the edge before heat treating.
I use all my leftover deep fryer oil (usually all peanut oil but also canola and other vegetable oils). Problem with all the motor oil and transmission oil crap you have there is that you don't know what all the additives are. There can easily be stuff in there that when burned can kill you. Vegetable oil is recommended in ALL of my collegiate level shop books for quenching in a small shop as is it safe to use, store, and it has a consistent viscosity no matter which one you use. Plus, it is dang cheap. Water was also recommended. Depending on what you are making. I like to use a 25 Gal metal garbage can and lid ( I have a lot of leftover oil from deep frying turkeys and such). Make sure it cannot melt whatever you put it into and has a lid....squirrels, rats, mice, dogs, cats...about any animal will want to get into it and you don't want Pepe the chihuahua face down in your bucket one morning.
For your holes....heat up the areas you need holes to orange and set it aside to slowly cool.....then drill the hole. Should be annealed then. The longer it takes to cool the softer it becomes.
No need to heat up the oil for any reason. That kind of process is used for salt quenches. Good luck
Awesome thanks for the info. So all I need to do is anneal the tang to make it softer. Is it ok to do this with a propane torch or should I anneal the whole knife in a coal fire in the grill because I'm just starting out and don't have a ton of money.
Sorry for all the questions I just don't want to mess anything up.
Drill annealed (prior to het treat) steel using a good/new bit - you should not have any problems.
the problem is that you don't really know what the steel is. An old saw blade could be a number of different steels. L6, 1045, 10xx... They don't all heat treat quite the same and the results of being wrong range from a broken blade during the quench to a less than fully hardened knife that won't stay sharp. If you have plenty of the blade to work with, cut some small pieces and test.
Regardless, I'd stick to the canola (or other cooking oil that you have around) or water. Water will result in cracked blades with some steels but it's basically free to try it. If you hear a distinct *ping* when quenching your sample piece don't use it for the blade. I do heat up the canola to 120 or so, it helps it quench the blade more efficiently and evenly.
If you have any identifying information on the saw blade you can do some googling and see if anyone knows what they're made out of, then you can get concrete info.