Handbook of construction plant, its cost and efficiency (1918)
Dana, Richard Turner, 1876-1928 · New York, McGraw-Hill book company, inc., [etc., etc.] · leaf 259
and drills can be sharpenedat the same machine by the same dies. Before this machine wasused two blacksmiths and two helpers were necessary, the ma-chine showing a saving over hand labor in 6 months of $1,738.50and saving in coal for 183 days, $83. Total saving for 6 months,$1,821.50. (No record…
Contractors' operations · Building
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