A hollow drift is a cylindrical tool of soft iron, or of copper, in one end of which is a recess of a cylindrical shape and about an inch deep. The tool is employed for protecting the centre recesses while driving out studs, pins, bolts, and other pieces of work that may be tightly fitted. An implement of this class is denoted by Fig. 423, and while in use it is held in one hand, with the recessed end of the tool in contact with one end of the pin to be driven out; the other end of the drift is then hammered with a small hammer or with a large one, according to the dimensions of the work in progress. A hollow drift may be of any convenient length for holding in one hand, when intended for small work; but for large work the drift may be short and attached to an iron wire or wood handle, to allow a sledge-hammering. When a bolt or pin is so situated in a hole that one extremity of the pin is at a distance from the mouth of the hole, it is necessary to use a drift which is of proper length to extend into the hole a sufficient distance to strike the end of the pin which needs driving out.