Making Tin Can Toys

by Edward Thatcher

A Simple Steam Turbine and Boiler.—A very simple and amusing steam turbine that runs with steam generated in a tin-can boiler may be made from tin cans. Select a well-soldered can with a tight-fitting lid, such as a molasses or syrup can with a friction-top lid. The lid will have to be soldered in place to make it steam tight.

Fig. 91.

Punch a hole about ¼ inch in diameter near one side of the lid for a filler hole. See that this hole is perfectly round so that a cork may be fitted in to make it steam tight.

The vane wheel should be about 3 inches in diameter and very carefully made. See that the axle is soldered exactly in the center of the wheel. The vanes should be small and numerous and each one exactly the same size. The method of construction is shown on [page 183] (full page drawing). A 3-inch circle is carefully laid out on a flat piece of tin and then another circle is laid off inside the first one about ¾ inch in. The outer circle is then divided up into 36 equal parts. Draw straight lines from each dividing dot at the edge to the center of the wheel. Bore a small hole exactly where each line crosses the inner circle. Cut down each dividing line to each hole. Use the pliers to turn each vane at right angles to the face of the wheel.

The steam nozzle should be very small. A triangular piece of tin may be formed around a fine wire nail or pin. The opening in the nozzle should be about ⅟₃₂ inch in diameter. The nozzle should be well soldered together and then soldered to the boiler, over a hole of a suitable size to allow the steam to flow from the boiler into the nozzle. Be sure not to solder up the tube so that the steam may not escape. A piece of broom straw may be placed in the nozzle when soldering it together, and it may be left in when the nozzle is soldered to the boiler. The straw should extend into the boiler and may be withdrawn when the soldering operations are completed. Do not use wire inside the nozzle to prevent it filling with solder as the solder will stick to it and prevent its being withdrawn.

Use care in placing the nozzle in position under the vane wheel so that the steam will strike the vanes squarely when it escapes. Set the end of the nozzle as close to the vanes as possible, but so that it does not strike the vanes when the wheel revolves.

These turbines run at very high speed when carefully made. Do not use too much heat under the boiler, as too great pressure may explode it with disastrous results. If the boiler is set over a gas flame, take care not to allow the flame to flare out around the boiler and creep up the sides, as it may then melt off the top of the boiler even when there is considerable water in it. A moderate flame will cause enough pressure to be generated in the boiler to make the vane wheel revolve rapidly. If care is used in fitting the cork in the filler hole, it may be made steam tight by pushing it into the filler hole with a light pressure so that if too much pressure is generated in the boiler the cork will blow out.

A pinion from a small clock works may be soldered to the vane wheel shaft and meshed in with a large gear which is set on a shaft soldered to the supporting upright at one side of the wheel. A small pulley may be made of wood or metal and fastened to the large gear. This arrangement of gears will give a reduced speed and a string belt may be run from the pulley to some light running toy machine. The pinion and gear fastened to the turbine should run very easily.