A. Neely Hall

An entire volume might be filled with plans for electrical toys and yet not exhaust the innumerable forms that are within the ability of a boy to construct. There is room in this chapter for only a few, and I have selected simple ideas, those that can be carried out by a boy having no knowledge of working with electricity, with materials that can be obtained at an expenditure of little or nothing. Thus every boy will be able to make these electrical toys.

The Electro-magnet Derrick shown in Fig. 176 will hoist nails and other small pieces of hardware from the floor to a table top, and as the boom, or arm, can be swung from side to side, and raised and lowered, loads can be moved from place to place in the same way as with large derricks. The toy derrick may be used for loading and unloading toy wagons, carts, and trains of cars, provided, of course, you use iron or steel of some sort for your loads. It is easy enough to get nails, brads, tacks, and odd pieces of hardware for the purpose. The model from which Fig. 176 was made has lifted a bunch of two hundred and eighty-four brads ³/₈ inch long. By using smaller brads, or tacks, a much larger number could be lifted.

The first part of the toy to construct is

The Electro-magnet. The difference between an electro-magnet and the toy variety of horse-shoe magnet with which every boy is familiar, is that the electro-magnet retains its magnetism only so long as an electric current is passing around it, while the steel magnet retains its influence permanently, after being magnetized, unless it happens to be demagnetized by subjection to heat, or in some other way.

Fig. 176.—An Electro-magnet Derrick.

Figures 177 to 179 show the details for making a simple home-made electro-magnet.

An electro-magnet consists of a center core of soft iron, wrapped with a coil of insulated wire. When an electric current passes over a wire, a magnetic field is formed around the wire; and when several turns of insulated wire are wrapped about a soft iron core, the magnetic fields of all the turns of the coil, or helix, combine, forming a very strong magnetic field which strongly magnetizes the iron core. As I have said before, this magnet loses its magnetic influence the instant the current ceases to pass through the surrounding coil of wire.

You will need a machine-bolt or carriage-bolt 2½ or 3 inches long, and ¼ inch in diameter, for the core of the magnet, some insulated electric-bell wire for the coil, and a piece of heavy cardboard. Cut three washers of a trifle larger diameter than the bolt-head, out of the piece of cardboard (Fig. 178), and slip these over the bolt as shown in Fig. 179—one at the bolt-head end, the other two at the nut end; then screw the nut on to the end of the bolt.

Before starting to wind the insulated wire upon the bolt, pierce two holes through the inner cardboard washer of the two at the nut end. Then stick the end of the wire through one of these holes, and pull a length of 4 or 5 inches of the wire out between the two washers. Starting at this end of the bolt, then, wind the wire around the bolt, keeping the turns even and each turn pressed close against the preceding turn. When the washer at the head end of the bolt has been reached, wind back to the starting point; then wind back to the washer at the head a second time, and again back to the starting point; and so on until six or eight layers of wire have been wound in place. An even number of layers will bring the free end of the wire back to the double-washer end. Slip this end through the second hole in the inner washer, and bring it out between the two washers, as you did the first end. Then screw the bolt-nut tight against the washers, to hold the wire ends in place (Fig. 177). The outer cardboard washer will prevent the nut from chafing the insulation on the wire ends.

Now connect the ends of the coil to the binding-posts of a battery cell, and you will be surprised to find what a strong magnet the head of the bolt core has become.

One end of the magnet coil should be connected to a dry-cell, and the other to a switch; and another wire should connect the switch with the dry-cell (Fig. 180).

A Home-made Switch that is easily made is shown in Fig. 181. Cut strips A, B, and C (Fig. 182) from a tomato can. Tack the turned up ends of A to a wooden knob (D). This forms the switch lever. Strips B and C, folded in half, and punched near the ends, form the binding-post plates.

Figures 181 and 182 show how to mount the lever and binding-post plates upon the switch base. Pivot lever A with a small screw passed through a hole punched near its end, and through the hole near the folded end of plate C. Fasten plate B with a rug-tack (F) so the lever will come in contact with it. Screw-eyes E form the binding-posts.

Instead of using a separate base, the switch can be mounted as shown in Fig. 176, upon the base of

The Derrick. Cut the base about 8 inches wide and 10 inches long (A, Fig. 176). The mast (B) is a piece of broom-handle or curtain-pole 16 inches long, and fits loosely in a hole bored in the base. Figure 183 shows a detail of the mast. The pulley upon its upper end (C) is made of two spool-ends nailed together (Fig. 184), and it turns upon the axle D, which slips through holes in the plates E nailed to the end of the mast. The lever F sticks in a hole in the mast, close to the platform. This is used to swing the boom from side to side. Screw-eye G is placed several inches above F to serve the purpose of a pulley to guide the hoisting cables.

Figure 185 shows a detail of the boom. Cut the side sticks H 18 inches long, and fasten between them the separators I, which should be just long enough to allow clearance for the spool pulley J. The pulley is mounted on the axle K. Screw the lower ends of the boom to the mast, at a point 2½ inches above the base.

The Windlass for raising the derrick boom, and for hoisting the loads, is shown in detail in Fig. 186. Bore a hole through upright L for the axle M to stick through, and cut axle M enough smaller than the spool drums N so they will turn easily. Fasten a crank and handle to one end of each spool, and drive a brad through each end of the axle to prevent the drums from sliding off. Cut four notches in the inner flange of each spool, as shown, and pivot the catches O to the post L, in the positions indicated, so they may be thrown into the notches to lock the windlass (Fig. 176).

The Hoisting Cables should be made of strong cord. Fasten one end of the cable for raising the boom to a nail (P, Fig. 176), and run this cord up and over the mast pulley, then down through screw-eye G and over to one drum; tie it securely to the drum so it will not slip around. The other cable should be fastened between the nut and washer of the magnet, as shown in Fig. 180, run up and over the boom pulley J, then through screw-eye G, and tied to the second drum.

Figure 176 shows how the dry-cell may be strapped to the base board in front of the mast, and how the wires that connect the electro-magnet, switch, and cell should be twisted around the hoisting cable, part way, and the remainder of their length allowed to hang. Be sure to cut the wires long enough to reach from a table-top down to the floor. Use flexible wire if you can get it.

By mounting the base upon spool wheels, your derrick can be moved along a table-top. Spool-ends may be used for the wheels, and can either be screwed to the edge of the base, or be fastened upon axles as the wheels of the Electric Motor Truck are fastened (Figs. 203 and 208).

How the Derrick Works. It is probably unnecessary to explain that a load is picked up by throwing over the switch lever to the contact point and closing the circuit, and that it is dropped by throwing off the switch lever and opening the circuit—which causes the electro-magnet to lose its magnetism.

A Toy Shocking Machine..The little shocking machine shown in Fig. 187 is a harmless toy with which you can have an endless amount of fun when entertaining friends. The shock it produces is not severe, but strong enough to make your friend's arm and wrist muscles twitch, and perhaps cause him to dance. Large shocking coils contract the muscles to such an extent that it is impossible to let go of the metal grips until the current has been shut off, but in our small shocking machine the handles can be dropped the instant the person holding them wishes to do so.

The shocking machine consists of an induction-coil, an interrupter, and a pair of handles, all of which are easy for a boy to make, and a wet or dry battery of one or two cells to furnish the current.

The Induction-coil is the first part to make. This is shown in detail in Figs. 188 to 191. The coil has windings of two sizes of wire upon an iron core. For the core buy a 5/16-inch carriage-bolt 2½ inches long, and for the wire coils get some No. 20- or 24-gauge electric-bell insulated copper wire, and some No. 30-gauge insulated magnet-wire. To keep the wire from slipping off the ends of the bolt core, cut two cardboard ends about 1½ inches in diameter. Slip one of these on to the bolt next to the head, and the other one next to the nut, as shown in Fig. 188.

Three layers of the coarse wire should be wound on first, for

The Primary-coil. Pierce a hole through one cardboard end, stick the wire through it, and allow about 5 inches to project upon the outside; then commence winding the wire upon the core, placing each turn close to the preceding turn. When the opposite end of the bolt has been reached, wind back to the starting point, then work back to the other end again. There will be in the neighborhood of 175 turns in the three layers. Cut off the wire so there will be a 5-inch projection, and stick the projecting end through a hole in the cardboard end. This completes the primary-coil (Fig. 189).

Before winding the small wire on top of the primary-coil, to form

The Secondary-Coil, wrap the primary-coil with a layer of bicycle tape, or glue several layers of paper around the coil. Then wind on the small wire as you did the coarser wire, being very careful to get it on evenly and smoothly. Wind eleven layers on the coil, and run the end of the eleventh layer out through the cardboard end (Fig. 190). There should be about 100 turns of this wire to the layer, or 1100 turns in all.

A crank arrangement can be rigged up to make the winding easier, but with patience, and by doing the work slowly, the wire can be wound almost as well by hand. It is difficult to keep track of each preceding turn, while winding, because of the fineness of the wire, and on this account it is a good scheme to coat each layer with bluing after it has been wound on, so that each turn of the following layer will show plainly against the stained layer beneath it. Fig. 190 shows the complete induction-coil.

Cut a base block 5 inches wide and 7 inches long, bevel the top edges to give it a trim appearance, and mount the induction-coil to one side of the center (Fig. 187), strapping it in place by means of two tin straps similar to that shown in Fig. 191, cut from a tin can.

The projecting ends of the primary-coil connect with the battery, while the two ends of the secondary-coil connect with the handles. Make three binding-post plates out of folded pieces of tin, similar to plates B and C, in Fig. 182. Tack two of these to the end of the base and connect the secondary-coil wires to them (Fig. 187), and tack the third near one end of the induction-coil and connect one primary-coil wire to it (Fig. 187).

For the Handles take two pieces of broom-handle 3½ inches long, and cover each with a piece of tin (Fig. 192). The pattern for the tin covering (Fig. 193) shows how tabs are prepared on the ends and holes punched through them for connecting with the induction-coil. The connecting wires should be 5 or 6 feet long. Flexible wire is better than bell-wire for these, because it is more easily handled in passing the handles around. Tack the tin covering to the pieces of broom-handle.

The purpose of the induction-coil is to raise the voltage of the battery. The flow of current must be an interrupted one, in order to shock, and therefore

An Interrupter must be inserted between the battery and one of the wires leading to the primary-coil of the induction-coil. There are several ways to construct an interrupter, but the scheme which I have invented for the model of this shocking-machine (Fig. 187) serves the purpose nicely, and is a neat appearing little piece of apparatus. This interrupter is easily constructed as you will see by the working details shown in Figs. 194 to 198.

Cut the base block A 1½ inches wide and 2½ inches long. Make the shaft B 2¾ inches long and of a diameter equal to the hole in a thread spool; and prepare the crank C to fit on the end, and drive a brad into it for a handle. Fasten the crank to the shaft with glue, or by driving a small brad through the two. The shaft supports D should be prepared as shown in Fig. 196, 1¼ inches wide across the bottom, ⁵/₈ inch wide at the top, and 1¾ inches high. Bore a hole through each, a little below the top, and large enough so the shaft will turn easily, and fasten these supports with brads to the sides of base A. Drive eight brads into a thread spool, spacing them equidistant from one another, and mount this spool upon the shaft (E, Fig. 194), first slipping the shaft through one support, then through the spool, and then through the other support. Drive the spool brads a trifle into the shaft to hold the spool in position.

The projecting arm F (Fig. 194) is a strip of tin cut from a can, and must be long enough so each nail-head will strike its end when spool E is revolved. Drive a nail into base A, at G, and, after bending strip F as shown in Fig. 198, fasten it with brads upon the top of an upright made similar to H (Fig. 197), and nail this upright to the end of base A. The upper end of strip F must be bent so it will bear down upon the head of nail G.

The wire from the primary-coil which is as yet not connected should be attached to nail G, and one battery wire should be connected to a binding-post plate I fastened to the lower end of strip F. Figure 198 shows how the binding-post plate is made out of a doubled piece of tin, with a hole punched through it for a small binding-screw.

This completes the interrupter. Mount it beside the induction-coil upon the base block, and connect it with the battery and the induction-coil, as shown in Fig. 187. Connect the battery cells in series. Two cells will be enough.

How the Interrupter Works. When you turn the crank of the interrupter, each nail in spool E raises the end of strip F, in passing it, thus breaking the electrical contact between it and the head of nail G. If the strip has been bent properly, it will spring back into contact with the head of nail G, and each time the contact is made, the person holding the handles will receive a shock. The strength of the current can be regulated somewhat by the speed with which the interrupter crank is turned. The shocks are stronger and more distinct when the crank is turned slowly.

Home-made electrical toys of a light construction are easily operated by a toy motor, when the motor and battery cell are not carried by the toy; but when both are transported, as in the case of a wagon, the construction must be very carefully worked out, or the motor will not be powerful enough to drive the wheels.

The Toy Electric Motor Truck shown in Fig. 199 is of light construction, the axle bearings produce very little friction, and the battery is light and of a powerful type.

Get an oblong shaped cigar-box for the bed and sides of the truck, several large thread spools for wheels and pulleys, two small silk-thread spools, four lead-pencils, or sticks whittled perfectly round and ¼ inch in diameter, for axles, belt-shaft, and steering-wheel post, and six screw-eyes 5/16 inch in diameter for the bearings.

First, place the cigar-box in a wash-boiler or wash-tub of hot water, and allow it to remain there until the paper labels have soaked off or loosened sufficiently so they can be scraped off with a knife.

Then, after the box has thoroughly dried, cut the two strips A (Fig. 208), and fasten them to the bottom, one at each side. Screw the screw-eye axle bearings into these strips. Place them at equal distances from the ends of the strips.

The Wheels are made from the flange ends of the large spools. Figure 202 shows the front pencil axle. Slip the center portion of one of the large spools on to this for a pulley, then stick the pencil ends through the screw-eyes in strips A, and glue the spool-end wheels on to them. The rear axle is like the front one, with the spool pulley omitted (Fig. 203).

The Upper Shaft shown in Fig. 201 supports a spool pulley like the one on the front axle, and its screw-eye bearings should be screwed into the top edge of the sides of the box (Fig. 200), directly over the front axle. Slip a silk-spool on to each end of this shaft to keep its ends from slipping out of the screw-eyes.

The Belts. As you will see by Figs. 200 to 202, the upper large pulley is belted to the motor pulley, and another belt extends from the upper shaft down to the pulley on the front axle. Rubber-bands make the best belts. Cut a hole through the bottom of the cigar-box for the belt extending from the upper shaft to the front axle to pass through. Screw the toy motor to the cigar-box with its pulley directly in line with the upper shaft pulley. Wrap the spool pulleys with bicycle-tape, to keep the rubber-band belts from slipping.

The Battery. A dry battery is too heavy for the motor truck to carry; so we must make a special two-cell battery like that shown in Fig. 204. Two glass tumblers to hold the solution, a pair of battery zincs, a pair of carbons, and a bi-chromate of potash solution, are needed. Old battery zinc pencils with several inches of the eaten end cut off (Fig. 206) will do for the zincs, and the carbons from worn-out dry-battery cells cut to a corresponding length will do for the carbons. Fasten together the zincs and carbons with rubber-bands, as shown in Fig. 207, after wrapping a piece of bicycle-tape around the upper end of the carbon and inserting a small wad of it between the lower ends of the carbons and zincs, to keep them from touching one another.

Figure 205 shows a completed cell, and Fig. 204 how the two cells are connected in series, that is, with the carbon of one connected to the zinc of the other. Twisting the connecting wires into coils, as shown, is a good method of taking up the slack.

The Bi-chromate Battery Fluid is made up of bi-chromate of potash, sulphuric acid, and water, in the following proportions:

4 ounces of bi-chromate of potash

4 ounces of sulphuric acid

1 quart of water

In making up this solution, first add the acid to the water,—never add the water to the acid—and then, when the solution is nearly cool, add the bi-chromate of potash. Pour the acid into the water slowly, because the combination of the two creates a great deal of heat, and if the heat forms too quickly your glass bottle is likely to split. Label the bottle in which you put this solution POISON.

As the bi-chromate solution attacks the zinc element of a cell even when the current is not being drawn upon, the zinc should be removed when the cell is not in use.

Amalgamating a Zinc Pencil. To reduce the eating away of a zinc pencil used in a bi-chromate solution, the zinc should be amalgamated by rubbing a thin coat of mercury over its surface. Dip the zinc into the solution, first, then with a rag dipped in the solution rub the mercury on to it.

Cut an opening through the cigar-box large enough for the two tumblers to set in. Then cut a strip of tin about 1 inch wide and 8 inches long, and bend it into a U-shaped hanger, to support the tumbler bottoms. Slip the hanger ends under strips A, bend them against the sides of the box, and fasten with tacks (Figs. 208 and 209).

Figure 200 shows how the battery cells are connected. A small switch can be fastened to the side of the truck to shut off and turn on the current, but, instead, you can simply withdraw one pair of elements from its tumbler to shut off the current. When through playing with the truck, however, it is important to remove both pairs of elements and wash them off, because the bi-chromate solution attacks the zinc elements even when the current is not in use. As the bi-chromate solution stains very badly, it is advisable to operate the motor truck only where there is no danger of ruining anything in case some of the solution spills, as in the basement or workshop. If you wish to use a dry-cell instead of the pair of bi-chromate cells, you can place the cell upon the floor and make the wires connecting it to the motor long enough so the truck can run back and forth across a room.

The Seat and Canopy-top details are shown in Fig. 210. Make these in about the proportion to the cigar-box shown in Fig. 199. Fasten the seat to the edge of the seat-back B with glue and brads, and then fasten the side pieces A to the ends of the seat. The dashboard E is nailed to the bottom piece D, and D is nailed to the lower ends of side pieces A. Figure 211 shows the pattern for the canopy-top. Make it of light-weight cardboard, or heavy writing-paper. Slash the ends as shown; then turn down the corners, and lap and glue them to form the turned-down canopy ends. Fasten the ends to the canopy uprights with tacks.

The Seat-arms are pieces of bent wire, with their ends stuck into holes in the canopy uprights and front edge of the seat.

The Steering-wheel is a section of a spool ¹/₈ inch thick, and is glued upon the end of a pencil or a stick. Run the lower end of the pencil through a hole in the bottom of D (Fig. 210). For

The Levers, fasten two small sticks to the end of the bottom piece D with small staples.