After the extremities of bolts are properly lined and centred, they can be immediately drilled and coned for turning, if they have been properly forged so that they are square to the bolt's lengths. If not, a species of preliminary lining and centring may be requisite to allow the rugged ends to be cut off, or at least to allow them to be properly shaped with a preliminary turning. If the extremities are not prepared with turning, they must be chipped, a hammer and chisel being employed to prepare a surface about half an inch around the intended recesses. The places for the recesses can now be shown by some of the modes described, and can be drilled with a fiddling-drill. When drilled, they are coned with a half-round coner, which is rotated with a hand-brace.

The diameter of each conical recess, when finished, should be about a tenth of the bolt's diameter ; and the small drilled hole must be deep enough to prevent the point of the lathe-pivot from touching the bottom; an eighth or a quarter of an inch of space being allowed between the pivot and the bottom of the hole. Consequently, if the fiddling-drill is not properly shaped to enter the metal far enough at the first drilling, the drill-hole must be deepened after the coning is completed.