Manual Training Toys for the Boy's Workshop Part 9

The nailing can be done while one arm of the wheels is held in the vise.

The axle and handle should be glued and nailed to the crank. Now put the reel together, not forgetting the washers inside the uprights, and lock the wheels to the axle by drilling a hole for a 2" nail thru cross piece, wheel, and axle.

[Ill.u.s.tration: KITE STRING REEL

PLATE 33]

[Ill.u.s.tration: STRING MACHINE

PLATE 34]

STRING MACHINE--PLATE 34.

On a machine like this, one can twist bowstrings, topstrings, fish-lines, silk cord for fancy work, and any similar cord. Tho designed to be held on the floor or table with flat-irons, clamps, of course, will hold it better.

Make the tail piece first. In the cross pieces of the tail piece are two screws 7/8" from the ends; be careful to bore the holes large enough so the screws will not split them. The edges of the lower cross piece must be sandpapered enough not to cut the elastic bands.

In order that the belt shall run on the center of the wheels in the head piece, it is important to have the three axles parallel. To make them so, the two uprights must be clamped together while boring the 3/8"

holes for the axles. Lest the spur of the bit split the uprights, drill small holes at each center first. Do not nail the longer upright to the base until the belt runs well in both directions. On a lathe, the wheels and axles could easily be made of one piece; lacking a lathe, a big spool or curtain pole must be used. Plug the hole of the spool with a dowel, then very accurately find its center and bore a 3/8" hole thru it. Saw it into three 5/8" pieces for the wheels. Glue these to the axles so that 1" extends thru the taller upright. A belt runs better on a wheel that is "crowned," that is, slightly larger in the middle; so the edges of these wheels must be pared 1/32", making a gentle curve.

Put the washers each side of the wheels, then put the wheels in place in the taller upright, and nail this to the triangular block. Pull a 5/8"

leather belt tightly around the three wheels and sew the ends so that they b.u.t.t together. Clamp the shorter upright in position and turn the upper axle to see if the belt runs well in both directions. It will run true when all three axles are parallel, so keep knocking the shorter upright from side to side or up and down until the belt does run true; then bore holes for three screws to hold it to the triangular block.

Make the crank and lock it to the upper axle with a 1/2" screw.

To twist a string, set the two parts of the machine somewhat farther apart than the finished length desired, put on as many threads, from hooks on the tail piece to corresponding hooks on the head piece, as will make the finished string the desired size. Observe how these separate threads were twisted, and start the machine in the _opposite_ way. Twist until the three strands kink readily when the head piece is brought nearer the tail piece. The tighter these are twisted, the harder the string will be. (Soap rubbed on the inside of the belt may make the belt carry more power). When these three strands are twisted enough, remove the two lower ones from their _hooks on the head piece_ to the upper hook. Twist in the _opposite_ direction until the string kinks again, and it is made. If the three strands are waxed, a stronger string will be made.

WINDMILL FORCE-PUMP--PLATE 35.

If this pump is properly connected with an air chamber, as explained later, it will send a small stream of water some ten feet. In a gale, the windmill is strong enough, in fact, to force the valves from the gla.s.s tubes. Like any model of considerable mechanism, this will require patience to get it in working order. The post is made short for stability. If it can be held in place firmly, a trestlework tower like a real windmill might be built of stock 1/2" 1/2" for the corner posts and 1/2" 1/8" for the braces.

The post is slanting on two sides to fit the journals at the top. It is fastened to the base with two 2" screws. Make the wheel center 2-1/8"

square, and thru its center bore a 1/4" hole. If it does not revolve true, make another block and try again. Make the block octagonal by cutting off each corner 5/8". On each of the eight faces saw notches 1/8" wide and 5/16" deep into which the vanes will fit. (See page 64 on cutting notches.) Make and glue the vanes in place and lay the wheel flat to dry.

Procure three pieces of water-gage gla.s.s 2" long, 7/16" to 1/2" inside diameter. Gla.s.s tubes can be broken apart by filing a slight notch, grasping the tube firmly each side of the notch, and pulling and bending the tube away from the notch. If the file starts a little break, this will be comparatively easy, if it does not, file some more. Into two tubes little valves must be cemented. These can be made of a firm piece of leather. Sole leather that is not too hard is best. With knife or chisel, pare two pieces on the cutting board to fit in the tubes. The cement will make them water tight later. Push the sharp point of a penknife into the smooth side of the leather disk and make a circular cut, as one would remove a speck from an apple, but do not cut the flap completely out, because it must be left hinged to the disk. Turn this flap up straight out of the way so as to be able to work a 1/4" hole thru the disk. This can be punched, drilled, or cut out with a 1/8"

chisel, and finished with a penknife. Of course, the edges of the flap should cover this hole completely. The valve in the lowest tube should be cemented about 1/2" from the lower end with the flap up, that in the horizontal tube about 3/4" from the outer end with the flap out.

[Ill.u.s.tration: WINDMILL FORCE-PUMP

PLATE 35]

To make sealing-wax sticky enough to cement these valves in the tubes, melt one teaspoon of wax with one-half teaspoon of turpentine in a large spoon, and allow it to cool. Break it in pieces small enough to go in the tubes. Put the valve in the tube a little to one side of its final position; put in some of the wax mixture; heat the tube in an alcohol flame, rolling the tube till the wax begins to melt; remove from the flame; and when the wax is all melted, push the valve to its final position with a pencil. While it is cooling, see that the wax does not flow into the valve. All three tubes must have a piece of rubber tubing on the outside to serve as packing in the wooden block. With an expansive bit, holes can be bored in the block so that the rubber tubing will fit tightly. Lacking that, bore a smaller hole and enlarge it with a round file. The center of the vertical hole is somewhat to the left (as viewed in Plate 35) of the center of the block to allow the horizontal tube more support. This will require the notch in the upright also to be to the left of the center. After the holes are bored, the pores of the wood must be filled with paraffin. In a little dish, melt some paraffin and put it into the holes with a rag tied to a stick. When the holes are well covered, drive the wax into the wood with an alcohol or candle flame held in the hole till the wood is fairly hot. The outside of the block might well be treated in like manner. It will be best to cement these tubes in their places. Melt a tablespoon of sealing wax with about as much turpentine. With this, not too hot, build up a good fillet over the rubber tubing 1/4", perhaps, on the gla.s.s tubes.

Make a good fitting piston for the upper tube; it must not slide hard (oil it) and yet it must be air tight. To make the piston file two grooves 1/2" apart around and near the end of the piston rod. Wind a hummock of yarn between these grooves till it almost fills the tube, then wrap a piece of soft cloth (knitted underwear) smoothly over the hummock, tying it in each groove with thread.

Lock the crank to the axle with a 1/2" screw. Adjust the axle and keep it in position with two leather washers locked to the axle just outside the journals. Clamp the block to the base, adjust it in line with the crank, and fasten it with two 1-1/2" screws up thru the base. The last connection to make is between the crank and connecting-rod. To make this, raise the piston to its highest position, and turn the crank to its lowest; choose what seems the best point for the screw, marking the point on crank and connecting-rod; now lower the piston and raise the crank; if the two points do not come together, the screw should be placed half way between them. This screw should be tight in the crank.

The wheel can now be glued to the axle or locked with a brad slanting from the front of the wheel center.

Before they will work, the valves must be made limber with water, and to start the pump, water may have to be put on each side of the valves.

Water may be pumped to any height by fastening a pipe to the horizontal tube. To obtain a steady stream, like a fire-engine, connect the horizontal tube with an air-tight bottle. The pipe which goes into this bottle should reach just below the stopper. The outlet pipe should nearly reach the bottom of the bottle, and it should have a nozzle smaller than any other opening in the whole apparatus. The bottle should be partly full of water. Quarter-inch gla.s.s tubing can be melted and shaped in an alcohol flame, and, if some rubber tubing is used as a connection, the nozzle can be played anywhere.