Triangulation applied to sheet metal pattern cutting : a comprehensive treatise for cutters, draftsmen, foremen and students ... (1920)
Kidder, F. S. (Fred SMith), b. 1863 · New York : The Sheet Metal Publication Company · leaf 178
cylindrical form of the least diameter must have the most rise per unit of measurement upon the base of the cylinder. Thus in every instance the throat must have a greater relative rise than the heel. Since vertical lines upon each are of equal lengths, the material which forms these portions must… … Fig. 82. Portions of Throat and Heel Connected to Duct. chapter, also in the note below. The vertical line E is presumed to be the vertical axis. The thirteen horizontal lines are presumed to be one line which has been revolved * The right helicoid is a surface which may be conceived as being…
Sheet-metal work
Internet Archive · Getty Research Institute · Public domain (published before 1931). Free to use for anything.
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