The practice of hand-turning in wood, ivory, shell, etc. : with instructions for turning such works in metal as may be required in the practice of turning in wood, ivory, etc. : also, an appendix on ornamental turning : a book for beginners (1868)
Campin, Francis · London : E. & F.N. Spon · leaf 217
given. We must now decide upon the number of apertures which we purpose having ultimately in each sphere. This being known, we commence by drilling holes of very small diameter from the points marked, for the centre of this aperture to the centre of the sphere; which holes are afterwards bored out… … various shells, the distance be¬ tween the centres of any three contiguous circles must be such that the parting -tools introduced at each
Turning (Lathe work)
Internet Archive · Getty Research Institute · Public domain (published before 1931). Free to use for anything.
