The First thing to be done for making the Drill, is to place half a Sheet of Paper to the Back of [Plate 2.] by pasting it on to its Margin; and likewise another half Sheet to [Plate 3.] in the same manner.
Then with a Needle prick through all the Out-lines of A, B, C, and D, in [Fig. 2.] which will mark out both Sides, and both Ends of the Mortise of the Turnep Drill-box. Also prick through the Out-lines of the great Hole in the middle of A, and of the elliptical Hole in B. Also prick the little Hole at E, in A; and at F, in B. Prick through the prick’d Line p q, in B; which is the Line to which the Setting-screw [Fig. 6.] or [Fig. 12.] that is to pass through the Hole in C, must be parallel.
When the Paper is taken off, cut out of it the said A, B, C, and D, by the Pricks made by the Needle.
Then cut the same in Pastboard, by laying these Pieces of Paper thereon (because Pastboard, being stiffer than Paper, will be more fit for the Use). Draw a Line with Ink on the pricked Line, p q.
B. Cole. Delin. et Sculp.
Plate. VI.
Page.408
The Hole in C must be something larger than in the Cut, because the Setting-screw must be so, being best to be of Brass, which is less apt to rust than Iron, of which Metal it was formerly made; but Brass, being weaker, requires the more of it to equal the Strength of Iron.
The Wreath, [Fig. 14.] is not necessary, because the Slider, [Fig. 15.] is sufficient without it; but then care must be taken, that the Edges of its Claws A B, which rub against the Cylinder of E, in [Fig. 9.] be taken off, to prevent their cutting it. This Slider is sometimes made of Brass, and sometimes of Iron.