I wanted to reinforce something Mike said. Randy mentioned the one second guideline for getting the blade from the fire into the quench oil. This is a common misconception. Where the one second comes in is mainly after you quench the steel.

It's not a good idea to dilly dally once you take the blade out of the forge or furnace, but steel doesn't air cool that quickly. Two or three seconds might be fine. Just move quickly to quench the blade, but don't rush.

Once you immerse the blade into the quenchant, the cooling speed of the oil becomes very important. Thicker oils, like motor oil, will disperse the heat more slowly, slowing the cooling process. Some steels are OK with slower cooling. However, a steel like 1095, for example, needs a thin, fast cooling oil. Preheating the oil to around 130 degrees F makes it more viscious, so it disperses the heat more quickly.

Each steel has its own formula, but basically you need to get it from it's critical temperature to somewhere between 600 and 800 degrees in a set timeframe, and then it can cool more slowly.