A screw press is a type of

machine press A forming press, commonly shortened to press, is a machine tool that changes the shape of a work-piece by the application of pressure. The operator of a forming press is known as a press-tool setter, often shortened to tool-setter. Presses ...

in which the ram is driven up and down by a screw. The screw shaft can be driven by a handle or a wheel. It works by using a coarse

screw A screw is an externally helical threaded fastener capable of being tightened or released by a twisting force (torque) to the screw head, head. The most common uses of screws are to hold objects together and there are many forms for a variety ...

to convert the rotation of the handle or drive-wheel into a small downward movement of greater force. The overhead handle usually incorporates balls as flyweights. The weights helps to maintain the momentum and thrust of the tool to make it easier to operate. The screw press was first invented and used by the Romans in the first century AD. It was used primarily in

wine Wine is an alcoholic drink made from Fermentation in winemaking, fermented fruit. Yeast in winemaking, Yeast consumes the sugar in the fruit and converts it to ethanol and carbon dioxide, releasing heat in the process. Wine is most often made f ...

and

olive oil Olive oil is a vegetable oil obtained by pressing whole olives (the fruit of ''Olea europaea'', a traditional Tree fruit, tree crop of the Mediterranean Basin) and extracting the oil. It is commonly used in cooking for frying foods, as a cond ...

production. The screw press was also used in

Gutenberg Johannes Gensfleisch zur Laden zum Gutenberg ( – 3 February 1468) was a German inventor and craftsman who invented the movable-type printing press. Though movable type was already in use in East Asia, Gutenberg's invention of the printing ...

printing press A printing press is a mechanical device for applying pressure to an inked surface resting upon a printing, print medium (such as paper or cloth), thereby transferring the ink. It marked a dramatic improvement on earlier printing methods in whi ...

in the mid-15th century. A press for

metalworking Metalworking is the process of shaping and reshaping metals in order to create useful objects, parts, assemblies, and large scale structures. As a term, it covers a wide and diverse range of processes, skills, and tools for producing objects on e ...

is a

machine tool A machine tool is a machine for handling or machining metal or other rigid materials, usually by cutting, Boring (manufacturing), boring, grinding (abrasive cutting), grinding, shearing, or other forms of deformations. Machine tools employ some s ...

used to shape or cut metal by deforming it with a die. It is frequently used to punch holes in

sheet metal Sheet metal is metal formed into thin, flat pieces, usually by an industrial process. Thicknesses can vary significantly; extremely thin sheets are considered foil (metal), foil or Metal leaf, leaf, and pieces thicker than 6 mm (0.25 ...

in one operation, rather than by cutting the hole or drilling. A screw press is often used in hand book binding to help keep the covers of books flat and parallel to the text block while the glue is drying. If used as a punch, the tool itself consists of a punch and a matching die, into which it very closely fits. Both are usually precision machined and then hardened. The material is introduced between the punch and die, and the machine operated. The punch will cut through the material in one movement by

shearing Sheep shearing is the process by which the woollen fleece of a sheep is cut off. The person who removes the sheep's wool is called a '' shearer''. Typically each adult sheep is shorn once each year (depending upon dialect, a sheep may be sai ...

it. The punch and die may be of any desired shape, so odd shaped holes and cutouts may be created. If used as a

forging Forging is a manufacturing process involving the shaping of metal using localized compression (physics), compressive forces. The blows are delivered with a hammer (often a power hammer) or a die (manufacturing), die. Forging is often classif ...

tool, the dies can be many different shapes varying from flat to various shapes that will mold the metal to the desired configuration.

Fly press

A ''fly press'' is a type of screw press in which the screw shaft is driven by a

flywheel A flywheel is a mechanical device that uses the conservation of angular momentum to store rotational energy, a form of kinetic energy proportional to the product of its moment of inertia and the square of its rotational speed. In particular, a ...

or a pair of ''fly'' weights at the ends of a bar. The wheel can either be cranked by hand or driven by a motor using a friction coupling. The wheel is weighted so its momentum will maintain the motion of the shaft. A fly press which is operated by hand is the simplest of all presses, it consists of mass, handle, body, arm, screw, ram, stop collar, treads, and guides.

Improvements

A planetary roller screw can provide about twice the maximum force as a screw press actuator using the same materials.

References

{{Metalworking navbox, formopen Press tools Metalworking tools