Or the rod may be built up of wooden
rods, well painted, alternating with brass at the points where the brackets
are.
[Illustration: FIG. 156.--Elevation and plan of vane.]
The Bevel Gearing.--Two brass bevel wheels, about 1 inch in diameter, and
purchasable for a couple of shillings or less, should be obtained to
transmit the vane movements to the dial arrow. Grooved pulleys, and a belt
would do the work, but not so positively, and any slipping would, of
course, render the dial readings incorrect. The arrow spindle (of brass)
turns in a brass tube, driven tightly into a hole of suitable size bored
through the centre of the post (Fig. 157). It will be well to fix a little
metal screen over the bevel gear to protect it from the weather.
[Illustration: FIG. 157.--Details of bevel gear and arrow.]
The Dial--This is made of tinned iron sheet or of 1/4-inch wood nailed to
1/2-inch battens. It is held up to the post by 3-inch screws passing
through front and battens. At the points of contact, the pole is slightly
flattened to give a good bearing; and, to prevent the dial being twisted
off by the wind, strip iron or stout galvanized wire stays run from one end
of a batten to the other behind the post, to which they are secured.
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