Jam Nuts are often used to lock or "jam" something in place without clamping against another object; Jam Nuts are typically low profile compared to a standard nut. ANSI B1.1 UNC and UNF Class 2B thread dimensions. Brass, composed of primarily copper and zinc, is highly corrosion resistant and electrically conductive. The use of brass, however, is somewhat limited due to its softness; primarily used for appearance.