Make the wheel of soft wood just as true as possible. (See [page 20].) For the axle a small brass rod or a large knitting needle may be used. In the center of the wheel, drill a hole smaller than the axle so as to make a tight fit. Be very careful to bore this hole straight. Force the axle thru the wheel, and if the wheel wobbles only slightly drive wooden wedges beside the axle to force it square with the wheel. If it wobbles too much, plug the hole and try boring again. Resting the axle on the jaws of the vise, revolve the wheel rapidly to see where it is out of true, and patiently pare it down. The flat side of the wheel which wobbles only a little can be planed off. The strip of screen wire netting should now be tacked on the wheel. It is long enough to go twice around the wheel, and should be tacked on with a dozen small tacks.
For suggestions about the pulley see [page 56].
Prepare a block of soft wood for the coupling. From its bottom, gage a line marking the height of the dovetails in which the blocks C and D fit 3/8" on each side. Saw these dovetails 3/16" deep, and pare them slanting with a chisel. In the center of the top, bore a 1" hole, 3/4" deep; continue the hole thru the block with a 1/2" bit. Bore holes 3/8" from the top, 1/2" from the ends for the two 1-1/2" screws which are shown in the small drawing, [Plate 20]. Gage and saw out the left-hand half of the block (as shown in the plate) as deep as the 1" hole. The purpose of this is to permit a squeezing fit on the threads of the faucet. When first trying it on the faucet, squeeze it hard with a hand-screw to jamb the threads into the wood; after that, the screws can be put in and the coupling attached at pleasure. A 1/4" hole is bored in the 1/2" dowel, which serves as a nozzle, until the spur just shows. Without allowing the bit to bore any farther, turn it around enough so that the spur will wear the wood and thus make a tapering hole as shown in the sectional drawings.
Prepare the sides, ends, and top of the box, the three blocks, the key wedge, and the two stops. The wedge should be 1/16" wider at one end than the other and should fit the dovetail. Block C should fit the other. In the top piece, bore a 3/4" hole in the middle 1-1/4" from the end. This hole is larger than the nozzle to allow for adjustments. All these parts must now be thoroly soaked with paraffin. Melt the paraffin, apply it with a brush to all surfaces, and drive it in with heat. During the process, the nozzle can be made fast in the coupling, using plenty of paraffin to make it water tight. See that the tiny outlet occupies the best position for directing the water onto the wheel. After the nozzle is cold again, the outlet should be carefully worked out again with the warm point of a big hat-pin or wire, filed to a good point.
Put the parts together as follows: Nail one side (the right in the plate) to the ends; screw the other side to ends; nail top to ends and first side only; nail block B to A; then A to the top. Unscrew the side and bore holes in the center of the sides for the axle. Make them fit nicely, then soak them with paraffin. Put the wheel, the side, the pulley, and the stops in place. Put the coupling in such position that the nozzle comes over the rim of the wheel and nail block C. After putting two or three soft leather washers in the coupling screw it to the faucet, lock it to the motor, and the motor is ready.
Better bearings for the axle can be made of two pieces of solder screwed to the inside of the sides. If these are made, the holes in the sides should be large enough not to touch the axle. The wheel and pulley can be locked to a brass axle by boring a hole thru the axle with a drill made of a needle. (See [Drills], [page 11].)
WATER MOTOR — Plate 20