Large factories, unlike cutting shops, produced finished buttons and were referred to as finishing plants. From shell to finished button, each piece was handled nearly 30 times. Workers completed one step in the process, and most were not considered craftsmen.
Women operated machines that removed bark from the blanks. They placed the blanks face down on moving belts that conveyed the blanks under large emery wheels. The Grinding Machine included suction tubes and blowers that removed excess dust.
The Barry Double Automatic was the centerpiece of pearl button manufacturing. The machines performed the functions of carving the design on the face of the button and drilling the holes two or four into the button. Women handfed smooth, flat button blanks into Double Automatics. As the chuck revolved, blades cut the pattern on the button face while drills formed the holes. A suction pipe lifted the button from the chuck and dropped it into a bucket under the machine.
Each finish plant contained rows of Double Automatic Machines. The work of seven shell cutting machines was needed to supply one Double Automatic, capable of producing over 150 gross or 21,600 buttons each day. Barry Manufacturing supplied these machines to finishing plants throughout the United States. The Double Automatic transformed the button industry by creating a more uniform pearl button that could be produced at one-fourth the cost. The machine helped secure Muscatines place in history as the Pearl Button Capital of the World. Because Barry made a high quality machine, many of the Double Automatics, after years of making pearl buttons, were adapted for plastic.
Pearl buttons were not finished until they received a lustrous polish. The first step involved tumbling the buttons with water and pumice. This removed the rough edges and made them ready for their final polish. Men transferred the buttons to a polishing barrel where the buttons were tumbled again. Steam and sulfuric or other acids aided in giving the button a pearly shine.
Girls often between the ages of 14 and 18 were generally employed for the task of sorting buttons. This tedious task was critical as factories could not sell mixed buttons. The girls graded the buttons by their manufacturing defects, natural stains, color, luster, and iridescence.
Buttons sold in retail shops were sewed to eye-catching cards. Many people women and children in Muscatine sewed buttons onto cards as this task could be done from home. Button factories distributed cards, loose buttons, and other supplies to local families and paid them for each complete card.