A blacksmith makes everything from plow shares to cooking utensils by heating raw iron in coal fanned by a hand-cranked turbine until it becomes red-hot and soft enough to pound, then repeatedly heating and shaping it because the metal cools very quickly. Through this repeated heating and pounding, the blacksmith forms tools, nails, bolts, horseshoes, and specialty utensils, while controlled heating and cooling create harder and softer sections that make tools both flexible and strong. Using skill, tongs, and a hammer, the blacksmith also works hand-in-hand with the wheelwright to shape metal bindings, iron tires, brackets, bands, and bolts custom-fitted to wooden wagon parts, giving the wagon the strength to hold heavy farm loads. Slightly undersized flat steel tires and hub bands are heated until they expand, placed on wooden wheels, and then quickly cooled with water so the shrinking metal forms a tight seal without bolts. Grinding stones were often used to put a fine edge on finished iron tools such as hoes and axes.