A spanner which has a boss at one end containing a square, six-sided, or round hole, is forged at one end of a bar which is nearly as thick as the length of the boss which is to have the hole. At the end of the bar a portion is reduced until small enough for the handle, and the thick portion adjoining is punched with a taper, square, or round punch, and also drifted while at welding heat with taper drifts of proper shapes. In Fig. 584, a spanner being made at one end of a bar is shown, and may be partly drifted while attached to the bar, and also afterwards, while separate, as denoted by Fig. 585. When it is cut from the bar, the shaping of the boss is completed by hammering the outside while at welding heat, and by fullers applied to the junction of the boss with the handle; during both these processes a drift is in the hole; a drift is also in the hole of a boss which is circular, and being rounded with half-round top and bottom tools.

The drifts for enlarging the holes are very taper, similar to the one shown in Fig. 585, and those for adjusting holes to proper diameters are so nearly parallel that they appear parallel to ordinary observation. A parallel drift is indicated in Fig. 586, and is tapered at each end, to prevent its being stopped by the burs made with hammering while being driven into or out of a hole.

Several drifts of various sizes and shapes are always kept ready by the smith, and by a proper use of the parallel ones, a spanner with a circular hole can be enlarged until the desired amount of metal remains for boring the boss to the stated dimensions ; and if the spanner being finished has a square or six-sided hole, it can be drifted until it fits the nuts, bolt-heads, spindle-end, plug-end, or other work for which the spanner is made, thus avoiding much filing, drifting with cutting drifts, and other lengthy processes.