Screw Rolling (forming) Machine, Patent Model, 1873
date: label: date made
content: 1873
label: patent date
content: 1873-09-09
name: label: inventor
content: Croft, Edward
notes: label: Description
content: This patent model is that of U.S. patent no. 142560, a screw forming machine created by Edward Croft of Waterbury, Connecticut. It is made of steel and painted red, and has the inscription, “June 16, 1873, Waterbury, Connecticut.” This date likely refers to the date on which this model was created as the patent itself was approved on September 9 of that year. Other screw making machines made screw blanks by rolling the screw between dues with indenting ridges. This would cause the metal compressed at one part to move to another. Croft sought to allow the metal to move more efficiently in the direction of the length of the screw blank, lessen the power required to forge screws, and diminish the errors often abundant in the current method of screw making. His innovation was therefore to have two converging dies with longitudinal indented ridges of progressively increasing pitch and concave profiles at the sides that correspond with the point of the screw. The effect of this would be to cause the blank to extend in length between the threads as the indentation or forging occurs so that the portions between the threads are progressively increased in length and decreased in diameter.
label: Location
content: Currently not on view
place: label: place made
content: United States: Connecticut
label: associated place
content: United States: Connecticut, Waterbury
setName: label: See more items in
content: Work and Industry: Mechanical and Civil Engineering
dataSource: label: Data Source
content: National Museum of American History
identifier: label: ID Number
content: MC.308813
label: catalog number
content: 308813
label: patent number
content: 142,560
label: accession number
content: 89797
objectType: label: Object Name
content: patent model, screw rolling machine
physicalDescription: label: Measurements
content: overall: 2 1/2 in x 11 3/4 in x 7 in; 6.35 cm x 29.845 cm x 17.78 cm