History
Historically, the first precise screwshafts were produced by starting with a low precision screwshaft, and then lapping the shaft with several spring-loaded nut laps. By rearranging and inverting the nut laps, the lengthwise errors of the nuts and shaft were averaged. Then, the very repeatable shaft's pitch is measured against a distance standard. A similar process is sometimes used today to produce reference standard screw shafts, or master manufacturing screw shafts.
Read more about this topic: Ball Screw
Famous quotes containing the word history:
“... that there is no other way,
That the history of creation proceeds according to
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Do get done in this way, but never the things
We set out to accomplish and wanted so desperately
To see come into being.”
—John Ashbery (b. 1927)
“Every generation rewrites the past. In easy times history is more or less of an ornamental art, but in times of danger we are driven to the written record by a pressing need to find answers to the riddles of today.... In times of change and danger when there is a quicksand of fear under men’s reasoning, a sense of continuity with generations gone before can stretch like a lifeline across the scary present and get us past that idiot delusion of the exceptional Now that blocks good thinking.”
—John Dos Passos (1896–1970)
“American time has stretched around the world. It has become the dominant tempo of modern history, especially of the history of Europe.”
—Harold Rosenberg (1906–1978)