Читать книгу Harper's Outdoor Book for Boys - Joseph H. Adams - Страница 32

The easiest sort of a pinion-wheel and weather-vane to construct is shown in Fig. 1. It consists of a piece of stout tin or sheet-iron, a wooden shaft twenty inches long, and a fan-tail twelve inches long and seven inches wide at the rear end.

Punch a small hole in the centre of a sheet of tin or iron not less than ten inches square, and with a lead-pencil compass draw a circle ten inches in diameter. Half an inch inside of this draw another one nine inches in diameter, as indicated by the light lines in Fig. 2. One inch from the centre draw a third circle making it two inches in diameter; then divide the disk into eight equal parts.

With a cold chisel cut on the lines, as indicated in Fig. 2, and bend the metal ears as shown in drawing No. 1, so that the corners will set back an inch from the rim. With a stout pair of shears cut around the outside line and free the wheel from the sheet of metal.

At the front of the wheel fasten a spool with steel wire nails driven through the tin to act as a hub. Then give them both a coat or two of paint.

Make a shaft from hard wood an inch square, and cut it in from one end about ten inches, as shown in Fig. 3. At the other end bind the wood for an inch or two with linen line or fine wire to prevent its splitting, and bore a hole in the end with an awl. Through the spool and disk, and into the hole in the shaft, drive a flat-headed steel wire nail or a screw, three-sixteenths of an inch in diameter, to act as the pinion on which the wheel may revolve.

From light wood, three-eighths of an inch in thickness, cut a fan-tail seven inches wide at one end and two at the other, and, having passed it through the cut in the shaft, make it fast with small nails or screws.

Balance the shaft and wheel on your finger to determine where to pierce the hole through which the upright shaft on the pole should pass; then bore it out with bit and brace so that the shaft will fit snug but not tight.

To the top of the shaft, over the hole, attach another spool, so as to form a longer bearing; or a strap of metal may be tacked so that it will bridge up over the hole about two inches. In this bridge a corresponding hole may be cut, through which the vertical shaft or pin will pass. This is to hold the vane steady on the long pin of quarter-inch round iron driven into the top of the pole, and prevent it from dipping forward or backward.

Place this vane on a shed, the end of a barn roof, or on a high pole where the wind has free access to it.