Part 110 (1/2)

[Ill.u.s.tration: Fig. 1; Trailer Attached to a Bicycle]

Instead of using a seat on the handlebars or frame of a bicycle for my little girl, I made a trailer, as shown in Fig. 1, to attach to the rear axle. I made it from old bicycle parts. The handlebars, which form the back of the seat, fasten into the seat post of an old bicycle attached to the trailer axle. The trailer is attached to the rear axle of the bicycle with two arms or forks, on the ends of which are two forgings, formerly used on the rear ends of a bicycle frame, brazed in, and one of the tube projections cut off from each to make a hook, as shown in Fig. 2.

The piece marked E shows one of these forgings or hooks in section. The original axle of the bicycle was removed and one 1-5/16 in. longer supplied, which was turned below the threads for clearance, as shown at A. A washer, D, with a hexagon hole was fitted over the regular nut C, on the axle, and filed tapering so the forging or hook E, on the trailer attachment, could be kept in position. The washer F is held tightly against the hook by pressure from a spring, G. The spring is held in place by a small nut, H, and cotter pin, 1. This attachment makes a flexible joint for turning corners. When turning from right to left the left hook on the trailer fork stays in

[Ill.u.s.tration: Fig. 2-The Hook in Position]

position, while the right hook pushes the washer F outward and relieves the strain on the fork. This attachment also makes it easy to remove the trailer from the bicycle. The washers F are pushed outward and the hook raised off the axle.

--Contributed by John F. Grieves, Providence, R. I.

** Home-Made Telephone Transmitter [398]

The parts for transmitting the sound are encased in a covering, H, made from the gong of an old electric bell. A round b.u.t.ton, D, is turned or filed from the carbon electrode of an old

[Ill.u.s.tration: Telephone Transmitter]

dry cell and a hole drilled through the center to fit in a binding-post taken from the same battery cell. This b.u.t.ton must be carefully insulated from the sh.e.l.l, H, by running the binding-post through a piece of small rubber tube where it pa.s.ses through the hole and placing a rubber or paper washer, F, under the carbon b.u.t.ton, and an insulating washer under the nut on the outside.

This will provide one of the terminals of the instrument.

Construct a paper tube having the same diameter as the b.u.t.ton and with a length equal to the depth of the bell case, less 1/8 in.

Glue or paste this tube to the b.u.t.ton so it will form a paper cup with a carbon bottom.

The diaphragm, B, which is the essential part of the instrument, should be made as carefully as possible from ferrotype tin, commonly called tintype tin. Cut a circular piece from this metal the exact size of the outside of the sh.e.l.l. A hole is made in the center of the disk a little larger than a binding-post that is taken from another old battery cell. When making the hole in the disk be careful not to bend or crease the tin. Sc.r.a.pe the black coating from the tin around the outside about 1/4 in. wide and a place about 1 in. in diameter at the center.

The second electrode, C, is made the same as D, and fastened to the tin diaphragm with the binding post without using any insulation. A third binding post, G, is fastened to the sh.e.l.l through a drilled hole to make the other terminal. The mouthpiece, A, may be turned from wood in any shape desired, but have a f.l.a.n.g.e on the back side that will make a tight fit with the outside of the sh.e.l.l.

Fill the paper tube with powdered carbon, E, which can be made by pounding and breaking up pieces of carbon to about the size of pin heads. Powdered carbon can be purchased, but if you make it be sure to sift out all the very fine particles. a.s.semble the parts as shown and the transmitter is ready for use. If speech is not heard distinctly, put in a little more, or remove some of the carbon and try it out until you get the instrument working nicely.

--Contributed by Harold H. Cutter, Springfield, Ma.s.s.

** Quickly Made Lawn Tent [398]

A very simple way of erecting a lawn tent for the children is to take a large umbrella such as used on delivery wagons and drive the handle into the ground deep enough to hold it solid. Fasten canvas or cotton cloth to the ends of the ribs and let it hang so that the bottom edge will touch the ground. Light ropes can be tied to the ends of the ribs and fastened to stakes driven in the ground in a tent-like manner to make the whole more substantial and to stand against a heavy wind. This makes an exceptionally fine tent, as the umbrella

[Ill.u.s.tration: Lawn Tent Complete]

is waterproof; also, there is more room to stand up in than in a tent that is in the shape of a wigwam.

--Contributed by J.A. Whamer, Schenectady, N. Y.

** How to Make a Windmill of One or Two Horsepower for Practical Purposes [399]

A windmill for developing from 1/2 to 2 hp. may be constructed at home, the expense being very small and the results highly satisfactory.

The hub for the revolving fan wheel is first constructed. One good way to get both the hub, lining, shaft and spokes for the blades, is to go to a wheelwright's and purchase the wheel and axle of some old rig. There are always a number of discarded carriages, wagons or parts thereof in the rear of the average blacksmith's shop. Sometimes for half a dollar, and often for nothing, you can get a wheel, an axle, and connected parts. Remove from the wheel, all but the four spokes needed for the fans as in Fig. 1. The same hub, axle and bearings will do. In case you cannot secure a wheel and shaft, the hub may be made from a piece of hardwood, about 4 in. in diameter and 6 in. long. A 2-in. hole should be bored through for a wooden shaft, or a 1-1/2-in. hole for a metal shaft.