Popular Science Monthly 



769 



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 



M-): 



v/ 





FIG. I. 

 A 

 a 



Fie. 2. 



FIG. 4. 



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. 



^"machine screws 



Two strips of metal 

 clamped together to form 

 piece for carburetor lever 



