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 59
F/g. 89 is also in quite general use. It is conveniently formed on a lathe,and does not require a special tool, or regrinding of the tool, asis the case for the U. S. Standard. The angle for both the aboveforms is 60 degrees. The Whit worth thread, or standard of Great Britain, is illus-trated in… … F/g. 90
Mechanical drawing
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