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Caliper

Caliper

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Description
A fairly crude caliper like this one was used for approximate measurements only, during the "rough" cutting of a diameter down to size. In the final, fine stage of a lathe cut, a much more precise caliper was used. A large caliper like this one was used by a machinist when operating a large lathe or vertical boring mill, making very large parts. The lathe might be an immense wheel lathe, one that "trued" the wheel treads of locomotive and railroad-car wheels. Or it might be a lathe for axles, in which the outer ends of each axle were machined for later fitting of wheels by a wheel press.
This tool is part of a collection of hand tools used in the inspection and repair of steam locomotives in Salisbury, North Carolina from the early- to the mid-20th century, roughly 1900-1955. Light repairs on steam locomotives were usually done in roundhouses at the many small locomotive terminals throughout a railroad's system; heavy repairs were done in a large, centralized repair shop serving the whole system (often referred to as the "Back Shop").
Object Name
Caliper
Date made
1930s
Associated Date
1820-Present
maker
unknown
Physical Description
steel (overall material)
Measurements
overall: 31 in x 17 3/4 in; 78.74 cm x 45.085 cm
ID Number
2002.0075.05
accession number
2002.0075
catalog number
2002.0075.05
Credit Line
Gift of National Park Service
subject
Railroads
See more items in
Work and Industry: Transportation, Railroad
Work
America on the Move
Transportation
Exhibition
America on The Move
Exhibition Location
National Museum of American History
Data Source
National Museum of American History
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