Essentials of drafting; a text and problem book for apprentice, trade and evening technical schools (1918)
Svensen, Carl L. (Carl Lars), 1884- · New York, D. Van Nostrand company · leaf 86
Fig i67 … Fig. /66 locates the centers of the bolt holes at a distance apart equal tothe diameter of the circle of drilHng. In such cases the otherholes need not be projected as they add nothing to the informationconveyed by the drawing. When holes are drilled as in Fig. 165they are said to be Two Up or off…
Mechanical drawing
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