Place the two pieces of wood together, the
piece between the two, and with a piece of stout leather hinge the two together, nailing the leather not only on the outside, but upon the top also; now screw a narrow batten on each of the pieces, about an inch from the widest end, to keep the wood from warping.
Four inches from the top (the hinge being the top) bore a hole through both pieces, and pass through a couple of strong leather laces; by one end fix these on the outside of the cheek to which the iron
is screwed, and on the outside of the other cheek, seven inches from the top, hinge a piece of wood (so as to fall toward the bottom) 5 inches by 2 by 1⁄2; and in the centre of the batten screwed on to prevent warping, fix a broad-headed nail or a turn-button, over which the free end of the leather laces can be passed.
Now about half an inch from each end drive through the wood, six or eight wire nails one inch long in a line, and so that the points project on the inside of each cheek. Next fix the top of the iron into the socket of the brace and the whirler is ready for use.
To use this instrument, lay it upon the bench, raise the upper jaw, place the grained zinc behind the teeth (face out) close the jaw, and after seeing that the face of the zinc is close up to the teeth, tighten the shoe lace, pass it over the hinged piece (which is lying down close to the cheek), and around the batten with two or three turns, then pass it back and tie the loose ends around the iron shank at the top; then raise the hinged piece, which by straining on the {42} leather laces will cause the jaws to grip the zinc plate tight and hold it in position. (See Fig. 4.)
Fig. 4. The Whirler.