American horological journal, devoted to practical horology (1869)
Miller, George B · New York, G. B. Miller · leaf 259
form shown at Fig. 5, a vertical cross section ofthe same at Fig. 6, showing itcut through radially, whichforms two cutting edges thatmake a thread as perfect asthat produced by the originalscrew cutting engine. However small the screw may be, these cutting edges take out a clean … AMERICAN HOKOLOGICAL JOURNAL. 253 chip of metal in cutting the thread, not onlyproducing a more nearly perfect screw, but withfar less torsion upon the blank than is requiredby such screw plates or dies as press the threadsupon the blank; and in screws of extremely smalldiameter this is no small…
Clocks and watches
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