The packer's hand is very ingenious (Fig. 169). It has the hook pierced by an eye enabling a thread to be passed through a basket as with a curved needle. The jaws of the pincers are smooth at the tips, but further back they have a series of graduated notches in which tacks of different sizes can be held whilst they are driven in with the hammer. But of course a workman can only work quickly if he can hold a number of tacks of the same size in the palm of his hand, placing one under the hammer, relaxing his hold of it after the first gentle blow has fixed it, and getting the next ready while he drives it home.
Fig. 169.—Packer's hand.
The plumber's hand (Fig. 170) is made in the shape of a pair of gas pliers, and ends in cutting edges with which wires can be cut. With them a bolt can be held whilst the other hand screws on the nut.
Fig. 170.—Plumber's hand.
The leather-cutter's hand (Figs. 171 and 172) should be able to hold the skin which the other hand cuts: it consists of a plate with a rough surface fixed to a ball and socket joint which allows it to turn in any direction, so that the other hand can follow the line to be cut which is often sinuous. This appliance may also be used to hold a drawing paper, a rule for cutting cardboard, or sheets of paper for binding.
Fig. 171.—Leather-cutter's hand.