_Tempering Steel Tools._--Good judgment is required to get the right temper. Good eyesight is needed to catch the color at the exact instant, and quick action to plunge it into the water before it cools too much. Dies are made very hard. The color of the steel at dipping time should be a bright straw color. Cold chisels will break when being used if tempered too hard. If cold chisels are to be used for cutting iron, the color should be violet; if the chisels are for cutting stone, purple is the color. Drills for boring iron are tempered a dark straw color at the cutting edge merging back into blue. The water in the dipping tub should be warm, as steel is likely to check or crack when it is tempered in cold water. [Illustration: Figure 91.--Blacksmith Hammers. Some smiths use a heavy machinist's hammer. But the flat peen is more useful when working around the anvil and the leg vise.] Tool steel should be held in a perpendicular position when it enters the water to cool all sides alike. Otherwise the new tool might warp. It is better to dip slowly, sometimes holding the point, or cutting edge, in the water while permitting the shank to cool slowly enough to remain soft. Some sizes of steel may be tempered too hard at first and the temper immediately drawn by permitting the heat of the shank to follow down almost to the edge, then dip. This is done quickly while watching the colors as they move towards the point or edge. _Draw-filing._--Making six-sided and eight-sided punches and scratchawls out of hexagon and octagon tool steel is interesting work. The steel is cut to length by filing a crease all around with a three-cornered file. When it is sufficiently notched, the steel will break straight across. To shape the tool and to draw out the point the steel is heated in the forge to a dull cherry red and hammered carefully to preserve the shape along the taper. Special attention must be given to the numerous corners. A scratchawl or small punch, must be heated many times and hammered quickly before cooling. An old English shop adage reads: "Only one blacksmith ever went to the devil and that was for pounding cold iron." After the punch or scratchawl is roughed out on the anvil, it is fastened in the vise and finished by cross-filing and draw-filing. Copper caps on the vise jaws will prevent indentations. [Illustration: Figure 92.--Vise Jaw Guards. Soft auxiliary vise jaws are made of sheet copper or galvanized iron.] [Illustration: Figure 93.--Roll Filing. To file a piece of steel round it is rolled by one hand while the file is used by the other hand.]