A screw press is exactly what the name implies; a press that has a large screw at its central core to generate a downward force. On most models, a handle or wheel is located at the top of the screw press to provide the torque in order to strike through metals and other objects, and a punch is attached to the bottom of the screw in order to present a sufficient sheering face. As the wheel is turned, the screw press strikes forward and punches out sections of metal. Components can be fashioned into many different shapes and sizes with a screw press; for example, the many cuts on the outer edges of table saw blades are created by using this method.
Unlike other tools that cut or grind through materials, a screw press relies on a single strike to create the incision. This is accomplished primarily through the extra weight within the upper handle, and since each strike only travels a short distance, a very large amount of force can be generated. Numerous punches are available for any one screw press to allow the operator to make specialized cuts of various dimensions, much like seasonally-inspired cookie cutters would inside kitchens and bakeries. Since the punches are quickly interchangeable, a single operator can switch from one project to another with ease.
Another type of attachment for a screw press is a die, which is an instrument used to shape light pieces of metal without puncturing them. This process is used to quickly create thousands of items and unique shapes within many different industries, and because the same shapes can be duplicated an unlimited amount of times, many factories also implement automated screw presses. Simple motors with reverse throttles are set up to allow the screw press to work along an assembly line, allowing them to stamp out or shape hundreds of items per minute.
The main benefits of using a punch and die with a screw press are the enormity of overall projects they can handle, and they are especially popular on projects that require oblong holes or patterns to be created. This type of machinery is limited to the thickness of metal that can be manipulated, however, and many factories will instead opt for more powerful types of presses that are operated by a pressurized piston. While there are certainly more powerful options available on the market, the screw press is still utilized worldwide in hundreds of thousands of businesses ranging from computer case manufacturers to aluminum framing companies.