Mechanick Exercises, or the Doctrine of Handy-Works

[even if the] work is filed and polished, [the drill] never batters or stretches it, but cuts a true round hole exactly in the spot where you first place it. You must have several sizes of drills, according to what your work may require. The shape in Figure 8 is enough to show its design original: "Fashion"; but it must be made of good steel and well-tempered. A marks the point, A B the shank, and C the drill-barrel. Note that the larger the drill-barrel is, the easier it rotates original: "runs about", but it will be less swift.

And just as you must be provided with several drills, you may also sometimes require more than one drill-bow, or at least several drill-strings. Use the strongest strings for the largest drills, and the smallest strings for the smallest drills. But you must remember that whether you use a small or strong string, you must keep your drill-bow straining your string quite stiffly, or else your string will not carry your barrel briskly around. Both your string and bow must be suited to the size of your drill; if both or either are too strong, they will break or bend your drill, and if they are too weak, they will not carry the barrel around as mentioned before.

The drill-plate or breast-plate is simply a piece of flat iron fixed upon a flat board. This iron has a hole punched a little way into it to hold the blunt end of the shank of the drill when you are drilling a hole. Instead of this, workmen often use a hammer, into which they prick a small hole on its side, and then set the hammer against their chest original: "Breast".

Of the Screw-plate and its Taps

The screw-plate is a plate of well-tempered steel with several holes in it, each smaller than the last. In those holes are threads grooved inwards internal threads for making screws, into which the corresponding taps that belong to them fit. The taps that belong to them are commonly made tapering toward the point, as Figure 7 shows. However, these tapering taps will not serve for some types of work, as I shall show in its proper place.