Lets start with the steel. All saws are not the same steel. Better to buy or obtain true spring steel so you know what you have. 1070, 1075, 1080, 1084. You can also use 1095, but it is a finicky steel to work with. Once forged and formed the spring should be annealed, then heat cycled from about 1600°, then 1500°, then just above non-magnetic. These 3 cycles consist of bringing to the temp, holding a few seconds, then air cooling until you can handle it bare handed. The cycling is what controls and reduces grain size, giving more strength. Then you can harden it. You never take steel to a yellow heat unless you are forging or forge welding. Yellow heat will produce a grain size so large as to see the individual grains. In hardening, no hotter than red-orange, and no less either. Quench in warmed canola oil, and have enough of it to cool fast. Not a tiny container like shown in that video. Springs need a temper heat of 725° to 750°. Don't ask why his spring worked, because there are too many unknowns and variables to give a proper answer, but I can tell you, that is no way to heat treat a spring. The guy knows how to shape one, but it all ends right there. Ok. I went back and he is using Celsius not Fahrenheit, so that is about 630/633° F in his temper, and that is too low for common spring steel. May work for a while, but risky if you got full hardness in quench, which I doubt he did considering the small amount of oil used and quenching at a yellow heat. That is one those variables I mentioned. A final word. When properly heat treated, a springs power is dependent on thickness and not temper. Temper controls it's breaking or set bending, while thickness controls power.
Topic: Making a Main Spring for your lock (Read 1963 times)