Finally, this fact should be emphasized, that in changing from flat shoes to those with calks, or the reverse, the hoofs must first be dressed in accordance, so that the foot axes will remain straight, and the feet be set always flat to the ground when the new shoes are on. Each hoof, when ready for the new shoe, should be let down and the horse allowed to stand upon it while it is again carefully examined and closely compared with the opposite hoof. Only after such close inspection has proved the dressing to be faultless can the hoof be considered as properly prepared and ready for the shoe. The two front hoofs and the two hind hoofs, when the legs are in the same position, should not only be of equal size, but also in proper relation to the size and weight of the body.
E. Preparing the Hoof for going Barefoot.
This becomes necessary when the nature of the ground and the kind of service required of the horse render shoeing unnecessary. However, to go barefoot the hoof must have plenty of horn. After removing the shoes the frog should be pared down nearly to the level of the wall, and the sharp outer edge of the wall well rounded off with the rasp, in some cases as far as the white line, otherwise large pieces of the wall will readily break away. Hoofs with very slanting walls must be more strongly rounded off than upright hoofs. Going barefoot strengthens the hoofs. From time to time the condition of these shoeless hoofs should be ascertained by inspection, and any growing fault in shape or direction of the horn immediately corrected. It quite frequently happens that the sharp edge of the wall must be repeatedly rounded, especially on very oblique walls (outer half of base-wide hoofs), and the quarters may require frequent shortening, because they are not always worn away as fast as the horn at the toe.
F. Making Shoes.[3]
Besides good, tough iron for the shoe, we need an anvil with a round horn and a small hole at one end, a round-headed turning-hammer, a round sledge, a stamping hammer, a pritchel of good steel, and, if a fullered shoe is to be made, a round fuller. Bodily activity and, above all else, a good eye for measurement are not only desirable, but necessary. A shoe should be made thoughtfully, but yet quickly enough to make the most of the heat.
The iron of which horseshoes are made is derived from the natural iron ore. Iron used for technical purposes is not chemically pure. Pure iron is rather too soft, and is therefore mixed with different substances, mostly with “carbon,” the most important ingredient of our fuel. Of course, the iron contains a very small quantity of carbon (0.5 to 5 per cent.). When iron contains more than 2.2 per cent. of carbon it is hard, brittle, and more easily melted, and is known as crude iron, or raw iron, because it is derived from the raw product,—black ore. The melted crude iron is called cast iron. Iron is ductile when it contains less than 2.2 per cent. of carbon, and is then called forge iron, or wrought iron. Wrought iron is fusible only at a high temperature. Only weldable iron containing less than 1.6 per cent. of carbon is suitable for general use. Of this iron we distinguish two sorts,—steel and wrought iron. A larger percentage of carbon is found in steel than in wrought iron. Steel is hard, can be tempered, and may be called tempered wrought iron. In order to temper or harden steel, bring it to a cherry-red heat, and then cool it suddenly by dipping it in cold water or wet sand. The tempered steel can again be softened as desired by heating and slowly cooling. By heating to a high temperature in a forge wrought iron will become doughy, and may then be intimately united (welded) with another piece at the same temperature by pressure or hammering. This property is called weld-ability; it is of great importance in making horseshoes. The heating of iron until it reaches the welding stage is called getting a “heat.” The act of welding wrought iron with steel is called “steeling.”
Fig. 101.
Fuller.
Fig. 102.