Page:Popular Science Monthly Volume 90.djvu/785

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Popular Science Monthly


��Making a Model Gyroscope from a Wire Spoke Wheel

EVERYONE knows that a top will not balance on its peg unless it is spinning; but few people understand what makes the top spin, or that in this simple toy lies the secret of the g>'roscope, which is being



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��gyroscope made from the front wheel of bicycle, and the manner of spinning it

��widely applied for steadying vessels, tor- pedoes, air-ships and mono-rail trains. With simple materials, anyone can make a gyroscope that will show many strange tricks of balancing.

The first thing required is a bicycle wheel, preferably a front wheel. If the tire is good, remove the valve plunger and pump the tire full of water. Then replace the plunger and pump in air until the tire is hard. If the tire is an old one, cut a hole in it and fill it with fine sand, covering the hole by winding it with tape. The object is to make the outer edge of the wheel as heavy as possible and keep the inner part as light as possible. 'If the wheel has no tire, and an old one cannot be procured, wind the rim with iron wire and cover the wire with tape, so that there will be no sharp edges to catch in the clothes.

Procure a piece of round iron, Fig. i , ^-in. in diameter by lo in. long and heat it red- hot; then flatten ^ in. of one end on an anvil. After making the end flat the length will be extended ^ in. Bore a hole 5/16 in, in diameter through the center of this flattened end, then bend the end to the shape shown in Fig. 2. The hole must come directly over the straight part of the rod, as shown by the dotted lines, and the bend must be sharp so that the nut will set firmly against a flat surface. To make sure of this, after the hole is bored and the iron heated almost white-hot on the

��end, dip about ^ in. of it into cold water. This will remove any tendency of the iron to bend in the vicinity of the hole.

Remove the outer, six-sided nut, from one side of the axle on the hub of the bicycle wheel and screw the rod into position as shown in Fig. 3. Screw the nut back until it holds the rod firmly. On the other side of the axle, without removing the outer nut, tighten or loosen, as the case may be, the inner nut or cone, so that the wheel will turn smoothly on its ball bearings. Then screw the outer nut against the cone so that it acts as a lock-nut to keep the cones in adjustment.

The g>Toscope model is now complete with the exception of a spinning stick. A piece of broomstick i ft. long is just right. In one end of it bore a ^-in. hole M-in. deep. Bevel the edges of the hole with a jack-knife, and round them nicely with sandpaper. Hold the wheel by firmly grasping the iron rod, and with the stick set it into rapid motion; then raise it to a position nearly upright and support the rod either with the stick, as shown in Fig. 4, or in the palm of the hand or with the finger-tip.

It may take some time to learn how to handle the gyroscope skilfully; in fact, I was kept busy chasing my first model about the backyard for some time until the knack of controlling it was acquired. There are numberless tricks that can be performed with this toy, and they will suggest them- selves as the owner becomes more ac- quainted with it. — E. P. Thornton.

Repairing a Broken Carburetor Lever on Automobile Engine

A BROKEN carburetor lever resulted in the temporary repair shown in the il- lustration. Two strips of steel ^ in. wide and 1/16 in.

thick were ,<^;01Carburetor valve annealed and bent in the shape shown. They were per- m a n e n t 1 y riveted to- gether at the pull-rod end and bolted at the other end where they clamped over the valve-stem head. Such a repair as this suggests a way to overcome a similar difficulty on the gasoline control line without waiting for an extra part. — Adolph Klein.

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Two strips of metal clamped together to form piece for carburetor lever

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