Build a brazing hearth by arranging a wall of fire bricks, at least 1 foot high, to the back of your metal table -- this will absorb excess heat during the hardening and tempering process. Place your steel to be heated in front of the wall, on top of one or two more fire bricks. The fire bricks are a safe heat-resistant surface on which to place steel during heating. For example, with a drill bit, heat the tip of it (the useful end) with the gas blow torch until it becomes red hot. The steel should be glowing red.
Pick up the drill bit using the blacksmith's tongs and plunge it into the metal trough of cold water. A hissing sound and steam will result. The tip of the drill bit has been hardened but it is very brittle. It will break easily if used and is not yet fit for purpose.
Clean the head of the drill bit with the emery cloth. Place the drill bit back onto the fire bricks of the brazing hearth. Heat the tip of the drill bit once again with the blow torch; this stage is called tempering. Observe the steel continuously because it changes color quickly. Watch for the steel changing to blue. This line of blue will travel towards the tip of the drill bit. Turn off the blow torch when the blue line reaches the tip, this shows that the required temperature has been reached.
Pick up the drill bit using the blacksmith's tongs. Place it onto a steel surface, for example, the surface of an anvil. The drill bit should be allowed to cool as the steel surface draws heat away from it. Tempering is complete when the drill bit is cold. It should no longer be brittle but instead tough and durable.