One of the first problems the amateur toymaker encounters when assembling mobile projects is the question of suitable wheels. Solid disk wheels are easy to mount on horizontally inserted screws or nails, but entail considerable care when cut out separately from plywood or solid stock. The time consumed in this sort of accurate workmanship can be better employed in the finishing and painting so dear to youthful eyes. The following suggestions are offered to speed up this phase of construction for mobile toys.

(1) Checkers make ideal disk wheels because they usually have a decorative, turned hub in their centers. To fit the standard board of 1/4 in. squares, checkers are usually 1 1/8 in. in diameter; the cheaper types are cut across the grain and average between 7/32 and 1/4 in. in thickness. For the sake of continuity, a thickness of \ in. will be used throughout this volume.

(2) A broom or mop handle averages about 7/8 in. in diameter, and can be sliced off in equal sections of any desired thickness. Larger wheels can be cut from wooden curtain poles, closet poles, drapery rods, rolling pins, or the poles upon which new rugs are rolled.

(3) Wooden spools, either whole or cut off near their flanges, are already bored for axles. The average thread spool has a hole of from 1/4 to 5/16 in. diameter, a flange which is an inch across, a shaft of about 13/16 diameter, and an overall length of 1 1/4 in. If used intact as a pair of wheels, this type of spool will restrict the width of a toy to if in., plus the thickness of the two sides. Narrow wooden ribbon spools can often be used effectively as separate wheels.

(4) The same is true of typewriter ribbon reels which average 2 in. in diameter or better. With their small holes they are easily mounted as the rear wheels of locomotives, paddle wheel frames for steamboats, or in sets of four for large toys. Ordinary film spools also have metal rims which are wider apart than those of the average wooden thread spool.

(5) Tiny toys will roll along on the thick disk heads of common wooden clothespins, which have been sawed off from their two-legged bodies and sanded where necessary.

(6) Small or medium tin can tops of the friction type are perfect circles insofar as their rims are concerned. When punctured in the center, they lack the necessary thickness to make stable wheels unless they are clamped between dowel sections and washers on the body side of the axle. Another method is to cut cardboard disks as fillers for the inner, or hollow side of the can top.

(7) A very simple but effective method of building up disk wheels for toys is to laminate them from cardboard. Since the various layers or disks, unlike wood, have no grain which must be placed at right angles to the next layer, all that is necessary is to scissor out enough disks to provide the required thickness when they are glued and clamped together. When several layers are used, a few tacks or phonograph needles inserted from one side will prevent slippage during gluing and add strength throughout the life of the wheel. The rim of a well glued, laminated cardboard wheel can be sanded, painted or lacquered for appearance and endurance.

(8) Ball bearing roller skate wheels can be mounted on screws or bolts as axles to provide excellent wheels for larger and heavier toys and will withstand considerable abuse.

(9) Equally durable are metal furniture casters which are swiveled on metal plates attached to the underside with four screws at the corners. They have the desirable feature of permitting the toy to turn sharply in either direction on their built-in pivots.

(10) Circular rubber erasers, enclosed between round metal guard or washers, will make silent wheels for small toys. Their diameters can be reduced, when necessary, by cutting the rubber down and sanding the new rim smooth.

(11) Model airplane wheels and axles are a deluxe solution to the problem of wheels for small toys. They can be housed unseen in model boats, tanks, or any hollow-bodied toy through slits cut in the bottom so that the axle can be equipped with staples as bearings.

The descriptions of the toys which follow will include as many of the above mentioned types of wheels as is practicable, on the assumption that personal preference and local availability will prove to be the deciding factors during manufacture.

Axles

The thickness and materials used for toy axles is in great part dependent upon the type of wheel employed, as well as such other factors as the housing and the function of the axle itself. Smaller types of wheels used on relatively light toys will operate satisfactorily on thin nails or screws driven horizontally into the base through moderately loose fitting holes in the wheels. The trick is to drive the nail or screw axles in at right angles to the base so that there will be no wobbling.

A full length axle made from a long bolt or a piece of stiff wire will require some sort of housings or bearings fastened to the base of the toy. Often these will consist of extensions of the sides, or may be composed of staples into the top or bottom of the horizontal base member. Larger axles, such as tightly fitting 1/4-in. dowels forced through 1-in. spools, may also be held in place by housings cut through the lower extensions of the sides, as in Figure 3.9. Frequently the base member itself will be thick enough so that smooth-shanked screws or nails can be driven into the edges to serve as individual axles (Figure 2.9). In such cases thin washers should be inserted between the wheels and the bearing surfaces of the toy to prevent binding; it is also a good idea to include an additional washer between the wheel and the screw or nail head of the axle. Thicker, dowel axles upon which the wheels are free to rotate have no heads, and must therefore be equipped with tiny cotter pins improvised from wire hairpins, paper clips, brads, or match sticks. A thin washer should be inserted between the cotter pin and the wheel, to protect the latter from excessive wear as well as from binding. If commercial metal washers are not available in small enough sizes, satisfactory substitutes can be snipped from tin or any thin sheet metal, provided the edges are smoothed and flattened.