This article illustrates the characteristics of pierced holes and summarizes the hole wall quality. Specific guidance in selecting die clearances is provided by considering the types of edges produced with different clearances. The article discusses the effect of tool dulling and the use of small and large clearance. It informs that the force needed to pierce a given material depends on the shear strength of the work metal, the peripheral size of the hole or holes to be pierced, stock thickness, and depth of shear on the punch. The article discusses the presses and tools used in piercing. It illustrates the use of compound dies, progressive dies, and transfer dies; piercing of thick and thin stock and piercing holes at an angle to the surface; special piercing techniques; and shaving of low-carbon steels.

This article discusses different factors for selecting progressive dies: costs, production volume, and press availability. It describes the purposes of strip development for a ring shaped part and presents the principles for the development of progressive dies. The article provides discussions on the general design features of progressive dies and the choice of proper auxiliary equipment such as coil feeders and scrap handling equipment. It concludes with information on different presses for progressive die work: open-back inclinable presses, four-column presses, and automatic underdrive presses.