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Wire-wound metering rods have been used for more than 75 years to apply liquids evenly to flexible materials. They were the first tools used to control coating thickness across the full width of a moving web. The 1980s saw a new popularity in rod use because of improved quality and the industry trend toward shorter converting runs. Wire-wound rods are used in a wide range of applications but find their greatest appeal in the manufacture of tapes, labels, office products, and flexible packaging. The first rods were made of ordinary carbon steel, wrapped with music wire. Today’s metering rods use precisionground core rods made of stainless steel, tightly wound with polished stainless steel wire at high speeds, on custom-designed winding machines. The resulting product is a laboratory-quality precision tool that can control coating thicknesses accurately within 0.0001 in. (0.1 mil). A typical wire-wound rod station is shown in Figure 18.1.