After sawing a board for the wheel 4-1/4" square, draw the diagonals and diameters (cornerwise and crosswise, that means) to divide it into eight parts. Draw a 4" circle for the wheel and a 3-1/4" circle to mark the depth of the notches for the paddles. Shape the wheel. (See [page 20] for directions.) Test it with the trysquare to keep the edge square with the flat surface. Bore a 1/4" hole in the center with the greatest care, or the wheel will wobble sidewise. The notches are cut with the back-saw alone. One-eighth of an inch to one side of the eight lines across the circle, saw straight down to the inner circle. Be careful to hold the saw square with the wheel. After this saw cut is made, measure the width of the notch by holding the edge of a paddle so as just to cover the saw cut, and, with a knife point make a dot at the other side of the paddle. Holding the trysquare against one side of the wheel and the inner edge of its blade over the dot, score a knife line across the edge of the wheel. Then saw straight down again inside this knife line. Saw cornerwise a few times and the wood will be removed sufficiently. The notches may better be too small than too large, for the paddles can be planed thinner to fit. Clean the wheel with the plane before nailing the paddles. All these paddles except one can be nailed with the wheel held in a corner of the vise. To nail that one, put a thin board upright in the vise and rest the wheel on its top. All nails should be started in the paddles, not in the wheel.
WATERWHEEL — Plate 19
Make the axle of hard wood. Push it thru the axle blocks and wheel, and lock it to the wheel with a brad, [Plate 19]. The axle is made long so that a pulley (spool) can be put on and a belt (string) run from this to other pulleys. A leather washer outside each axle block keeps the wheel in the center. If the work has been carefully done, the paddles will not strike; if they do strike, they must be pared off.
[WATER MOTOR—][Plate 20].
This motor is a waterwheel designed for an ordinary hose faucet. Under a stream of water no bigger than a large needle, it will fairly buzz. If the wheel does not run exactly true on the axle, the motor will need legs screwed on the outside of the box.