Chapter XXII: Part III: Construction of the Track System (1)

Operation of the electric-locomotive model described in the previous articles is feasible only with a properly constructed track system. This equipment, including curves and switches, is to be described in this, the final, article. Two functions are to be performed by the track system: It must serve as a support and guide for the locomotive and provide a path over which the current from the source of energy is supplied to the motor within the locomotive and returned to the source. On this basis, then, the construction may be divided into two parts: the mechanical and the electrical features. If the mechanical construction is not practical and accurate, the locomotive will not operate satisfactorily. The electrical connections must be given due care also.

FIG. 1

RAIL CONNECTION

FIG. 2

Shape the Rails from Sheet-Metal Strips, 1¹⁄₂ Inches Wide and 16 inches Long, to the Form Shown in Fig. 1. The Rail Connections are Formed as Shown in Fig. 2]

The track should be of uniform gauge; the joints should be solid and free from irregularities, which cause “bumping” in passing over them. The material used should be stiff, so that it will retain its form, and preferably non-rusting. The rails must be insulated from each other, and proper means must be provided for making suitable electrical connections between the various sections. The construction of a straight and a curved section of track, together with a switch and signal, adaptable to various places on the system, will be considered in detail.

The straight sections may be made any suitable length; sections 16 in. long will be found convenient, as the metal pieces forming the rails may be bent into shape easily when they are short rather than long. The possibility of various combinations of straight and curved sections in a given area is increased by having the sections shorter. The rails may be made from tinned sheet-metal strips, by taking pieces, 16 in. long and 1¹⁄₂ in. wide, and bending them into the form shown in Fig. 1. The rails should be mounted on small wooden sleepers, ¹⁄₂ by ¹⁄₂ by 4 in., by means of small nails, or preferably small screws. The distance between the centers of the rails should be 2 in. The sections of track may be fastened together at the ends by means of a special connector, shown in Fig. 2, made from thin metal, preferably spring brass. The type of connector shown in Fig. 2 will not prevent the sections from pulling apart, and to prevent this, a second connector, similar to that shown in Fig. 3, should be made. The sleepers at the ends of each section should have one side beveled, as shown, and these edges should be exactly one inch from the end of the rails. A spring clip should be made, similar to that shown, which will slip down on the inside of the end sleepers and hold the sections together.

FIG. 3

SECTION OF RAIL

FIG. 4

END CONNECTION OF RAILS

FIG. 5

A Spring Clamp for the Joints in the Sections is Shown in Fig. 3. An Improved Form of Rail is Shown in Fig. 4, and in Fig. 5 is Indicated the Method of Joining Its Sections]

A better form of rail is shown in Figs. 3 and 4, but it is somewhat more difficult to construct. In this case, instead of bending the piece of metal forming the rail over on itself and closing the space entirely, the metal is bent over a round form, such as a piece of wire, which may be removed, leaving an opening through the upper part of the rail from end to end. This gives a better form to the tread of the rail and at the same time provides an easy means of connecting the ends of the rails, as shown in Fig. 5. Small metal pins, about 1 in. long, and of such a diameter that they will just fit the circular opening in the top of the rail, are provided. One of these pins should be fastened in one rail at each end of a section, making sure that no rail has more than one pin in it, and that the arrangement of pins and rails corresponds in all sections. With proper care the various sections should fit together equally well, and they may be held together as shown in Fig. 3.

FIG. 6

LEFT SWITCH

FIG. 7

RIGHT SWITCH

FIG. 8

Lay Out the Switches and Curves, Full Size, and Fit the Rails to the Curves Accurately]

The curved sections may be made from rails similar to those described above, but some difficulty will be experienced in bending them into a curve because of the necessity of bending the lower flange on edge. The difficulty may be overcome by crimping in the inner edge of the lower flange and expanding the outer edge by hammering it on a smooth surface. The radius of the curve to which the inner rail should be bent in order to give a section of convenient length, and not too abrupt a curve, is 21 in. The circumference of such a circle is approximately 132 in., which, divided into eight sections, gives 16¹⁄₂ in. as the length of the inner rail of each section. Since the tread of the track is 2 in., the radius of the curve of the outer rail will be 23 in. The circumference of the circle formed by the outer rail is 145 in., which divided into eight sections gives 18¹⁄₈ in. as the length of the outer rail of each section. These curved rails may be mounted on sleepers, their ends being held in place, and the various sections fastened together, just as in the case of the straight sections.

Some trouble may be experienced in getting the curved rails properly shaped, and it would be a good plan to lay them out full size by drawing two circles on a smooth surface having diameters of 42 and 46 in., respectively, and divide each of the latter into eight equal parts. The form of the curve between these division lines and the lengths of the curves will correspond to the shape and lengths of the rails forming the curved sections of the track. The pieces should be cut slightly longer than required, and after they are bent into shape their length can be determined precisely and extra portions cut off. Each curved section will correspond to ¹⁄₈ of the complete circle, or 45°, as shown in Fig. 6.

The switches for the track may be of two kinds: left and right. They are named according to whether the car is carried to the left or right of the main track with reference to the direction in which the car moves in entering the switch. A left switch is shown in Fig. 7, and a right switch in Fig. 8, the direction of movement being indicated by the arrows.

FIG. 9

The Crossings of the Rails must be Fitted Carefully, and the Movable Sections G and H Arranged to Make the Proper Contacts]

A detailed drawing of a right switch is shown in Fig. 9. Rail A corresponds in form and length to the outer rail of one of the curved sections previously described; rail B corresponds to the inner rail of one of the curved sections except that 2¹⁄₂ in. of straight rail is added at the left end. Rail C is a straight portion of rail, 18 in. in length, with a part of the base cut away at the switch, and rail D is a section of straight rail, 15¹⁄₂ in. in length, with the base cut away where it crosses rail A. The ends of rails D and A are hinged at the points E and F, 3³⁄₄ in. from the left end, with pins driven into the ties. The outside edges of the pieces G and H are filed off so they will fit up against the rails C and B respectively. Both the pieces G and H are attached to a strip of fiber insulating material, I, at their left-hand ends, in such a way that when the piece H is against the rail B, the piece G is away from the rail C about ³⁄₁₆ in.; when the end of the piece G is drawn over against the rail C, the end of the piece H is drawn away from the rail B about ³⁄₁₆ in. With these two combinations the car may be made to move along the main track or to the right on the curved track. The two long sleepers J and K are to provide a mounting for the switch-control lever and signal.

The rail A is not continuous where the rail D crosses it, but is broken as shown in the figure. A small notch should be cut in the surface of the rail D where it crosses the rail A, for the flange of the car wheels to roll through when the car is moving onto or off the switch. The sections of the rails A and D must be connected electrically. Rail A must be connected to rail C, and rail B to rail D.

It is obvious from an inspection of Fig. 9, at L, that rail D will be connected to rail A when the car is on the switch, the car wheels passing over the point L, and a short circuit will result. This may be prevented by insulating the short section of the rail D at this point from the remainder of the rail, but the length of the insulated section must not be greater than the distance between the wheels on one side of the car; otherwise the circuit through the motor would be broken. If this is the case, and the car stops on the main track with both wheels on the insulated section, it would be impossible to start the locomotive until one wheel was moved to a live part of the rail.

The switch control is shown in Fig. 10, and the letters C, G, and I correspond to those given in Fig. 9. A ¹⁄₈-in. rod, about 4 in. in length, is bent into the form shown at M. It is mounted in a frame, the details of which are shown in Fig. 11. A small arm, N, with a hinged handle, O, is soldered to the rod, after it is placed in position in the switch frame. The arm N and the lever P should be parallel with each other. If properly constructed, the handle O will drop into the notches in the top of the switch frame, and prevent the rod M from turning. A connection should be made from the lever P to the end of the piece I, which will result in the switch being operated when the rod M is rotated one-fourth of a turn. After this connection is made, the frame of the switch should be fastened to the ends of the long sleepers, which were provided when the track part of the switch was constructed. Two small disks, mounted at right angles to each other, will serve as signals when properly painted, or as an indication of the open or closed position of the switch.

FIG. 10

TOP VIEW SWITCH FRAME

FIG. 11

The Signals Indicate the Open or Closed Condition of the Switch by the Small Disk, Which is Regulated by the Lever Switch Control]

The speed of the car on the track may be controlled by inserting resistance in series with the battery or source of electrical energy, or by altering the value of the voltage between the rails, by changing the connections of the cells forming the battery. The direction of movement of the locomotive cannot be changed unless the car is turned end for end, or the connections of the armature or field winding--not both--are reversed. The switch on the bottom of the locomotive reverses these connections.

A small rheostat, which will give the desired resistance, may be constructed as follows: Obtain a piece of hard wood, 4 by 5 in., and ³⁄₈ in. in thickness. Lay out a curve on this piece, as shown in Fig. 12 by the row of small circles. Procure eight round-headed brass machine screws, about ¹⁄₈ in. in diameter and ³⁄₄ in. in length, and 16 nuts to fit them. Drill eight ¹⁄₈-in. holes along the curve, spacing them ³⁄₈ in. apart. File the heads of the screws off flat and mount the screws in these holes. Make a metal arm, S, and mount it on a small bolt passing through a hole drilled at the center from which the curve was drawn, along which the screws were mounted. This arm should be of such a length that its outer end will move over the heads of the screws. Mount two binding posts, Q and R, in the upper corners of the board and connect R to screw No. 8, and Q to the bolt holding the arm S in place. Connect small resistance coils between the screws, starting with screw No. 2; screw No. 1 corresponds to an open circuit and is shown in contact with the arm S. Two stops, indicated by the black spots, should be provided, to prevent the arm from moving back of screw No. 1 or beyond screw No. 8. The board may now be mounted on a suitable hollow base, and the rheostat is complete.

Two binding posts should be mounted on the ties of one section of the track, and one of them electrically connected to each of the two rails, which will give an easy means of making the necessary electrical connections to the source of energy. After careful examination, to make certain that the locomotive is in running order, a test run may be made. If the locomotive operates properly and difficulty is experienced when it is placed upon the track, check up thoroughly on all rail connections, insulations, and other elements in the electrical equipment. Cars of a proper gauge may be coupled to the locomotive, and “runs” made as extensively as the track system will permit.

Sleeve Aids in Distinguishing Gas-Fixture Chains

Annoyance through inability to locate quickly the proper chain for lighting a gas lamp in the dark was overcome by fitting a small brass tube to one of the chains as shown in the illustration. The tube was soldered to the chain by which the light is turned on and the other chain passes through the tube and is grasped below it. To turn on the light, it is only necessary to slide the hand along both chains and to grip the tube, drawing on the chain attached to it. To turn the light off, the exposed end of the other chain is drawn.--Thomas W. Benson, Hastings upon Hudson, N. Y.

An Ornamental Horn Match Holder

A match holder made of the horn shell of cattle hoofs mounted on a wooden shield, as shown in the sketch is both ornamental and useful. One of the pockets holds the unused matches and the other the burnt ones. The hoofs were cleaned thoroughly and polished and the edge of the shield was beveled off and varnished in the natural color of the wood. The front was lacquered black and also varnished.

* * * * *

¶A small flat piece of wood is convenient for pointing up an eraser.

Driving Thin Metal into Wood

A slender piece of flat, or round, metal may be driven into a wood handle without breaking the wood or bending the metal, if it is placed in a vise and the wood part driven onto the small portion projecting from the jaws of the vise. Repeat the operation until the metal is driven far enough into the wood.

Slicing Board for Camp or Kitchen

The board illustrated was suggested by a device used by a “sandwich man,” and proved practical for use in the home and especially in the camp. Potatoes, or other articles of food to be sliced, are placed in the hollow portion of the board and moved against the edge at the right, under the knife. The guide, which may be adjusted by means of the wing nut, permits slices of varying thickness to be cut.--Robert C. Knox, St. Petersburg, Fla.

Cleanly Pencil Sharpener

Pencils may be pointed without spreading the dust from them by the use of the device shown in the illustration. A piece of emery paper is fixed to one side of the cover of the box. By turning over the cover with a handle, after a pencil has been pointed, the dust may be dropped into the box and removed from time to time.--Sidney Block, Detroit, Mich.

A Weeding Tool

B

A Case-Knife Blade Bent and Fastened in a Broom Handle Makes an Excellent Weeding Tool]

A handy weeding tool may be made of an old case knife--one of the kind having a wood handle is the best. Remove the handle sides and heat the blade about 1 in. from the end, then bend it at right angles as shown at A. Ream out the rivet holes in the handle large enough to allow screws, about 1 in. in size, to enter. Procure an old broom handle and saw a slot in one end deep enough to receive the knife shank, and fasten it with screws, as shown at B. This makes an excellent tool for removing weeds from beds of young radish, lettuce and other plants, as it is possible to get close to the plant stem without injuring it.--Contributed by L. G. Burnand, Lyons, Iowa.

Spray Nozzle Made of Acetylene Burner

An acetylene burner makes a first-class spray nozzle, even though the lava tips are broken off level with the metal. The burner may be secured on a short piece of pipe, as at A, and this inserted in a hose, or it may be pushed into a hose and wound with wire, as shown at B.

Clamping a Wide Board on a Bench

Having occasion to cut a groove on the surface of a board too wide for the vise, I rigged up the arrangement shown to hold it. The board was laid on the bench with the edge slightly projecting, then I nailed a block firmly to the bench, close to the edge of the board, and placed a stick in the vise as shown. When the vise screw was turned up, the board was gripped solidly.--Contributed by S. H. Bosuston, Victoria, B. C.

Feeding Pan for Poultry

An excellent water or feeding pan for small chicks can be made of concrete. Take an old pan and place it in an inverted position in a shallow box, as shown in the sketch, then mix the concrete and pour it over the pan. When the cement sets, turn it over and a pan will be had that small chicks can climb out of, should they get into it.

Metal Floor Corners

The hardest part of a room or stairway to clean is the corners, and these always collect a good quantity of dirt. Instead of removing the dirt each time, a better plan is to fix the corner as shown in the illustration. A triangular piece of brass or copper, 2 in. on each side, is fastened into the corner with one nail through the center. These metal pieces are especially desirable in public buildings.--Contributed by Abner B. Shaw, N. Dartmouth, Mass.

Measuring Resistance with a Lead Pencil

BY JOHN D. ADAMS

There are very few electrical experimenters who can afford a Wheatstone bridge for measuring resistances, and yet, if one is to gain any knowledge from his experiments, it is very necessary to know what resistance is being used, particularly in handling 110 volts. The amateur will find the following method very useful.

There are several brands of lead pencils, the leads of which have a resistance of 200 to 300 ohms, while others have comparatively little resistance. Soak several pencils--preferably the large kind carpenters use--in water over night so that the leads may be removed without breaking. Connect up two 40-watt lamps in series and note how they burn. Then replace one lamp with a lead and note the relative intensity with which the remaining lamp burns. If the lead is of a sufficiently high resistance it will cut down the illumination about as much as the additional lamp.

Having selected a lead, mount it on a suitable board, holding it in place by clamping each end under a strip of brass held down with wood screws. Next screw in place two porcelain receptacles and place three binding posts in position, all as shown in the sketch. Connect up as indicated, and attach a short length of flexible cord, with a metal tip on the free end, to one terminal of the central receptacle. Procure a cheap 75-ohm receiver and connect it to the two ends of the pencil lead. Finally glue on a paper scale.

To operate, place a high-resistance lamp in the center receptacle--say, a 15-watt lamp--to prevent heating, and almost any lamp of known wattage in the other receptacle. From the rating of this lamp the resistance may at once be determined by Ohm’s law. Thus, at 110 volts, a 25-watt lamp will have a resistance of 484 ohms; a 40-watt lamp 300 ohms, and a 60-watt lamp, 200 ohms. Connect the unknown resistance, as shown in the drawing, and move the metal tip on the end of the flexible cord back and forth along the pencil lead until a point is reached where no sound is emitted by the receiver. This point will be very well defined, and as the connection is moved away from it in either direction the sound will increase rapidly. Note the reading on the scale, and then if a 40-watt lamp is used in the end receptacle, the unknown resistance will be

300 A
= -----.
B

The resistance of the center lamp does not enter into the computation, but by changing the lamp in the end receptacle, another set of figures may be obtained, and a means had to secure increased accuracy.

A Simple Motor Controller

The controller described is very similar in operation to the types of controllers used on electric automobiles, and its operation may be easily followed by reference to the diagrammatic representation of its circuits, and those of a two-pole series motor to which it is connected, as shown in Fig. 1. The controller consists of six flat springs, represented as small circles and lettered A, B, C, D, E, and F, which make contact with pieces of narrow sheet brass mounted on a small wood cylinder, so arranged that it may be turned by means of a small handle located on top of the controller case in either direction from a point called neutral, which is marked N. When the cylinder of the controller is in the neutral position, all six contact springs are free from contact with any metal on the cylinder. The contacts around the cylinder in the six different horizontal positions are lettered G, H, J, K, L, and M. There are three different positions of the controller in either direction from the neutral point. Moving the cylinder in one direction will cause the armature of the motor to rotate in a certain direction at three different speeds, while moving the cylinder in a reverse direction will cause the armature to rotate in the opposite direction at three different speeds, depending upon the exact position of the cylinder. These positions are designated by the letters O, P, and Q, for one way, and R, S, and T, for the other.

Diagram of the Electrical Connections of a Controller to a Two-Pole Series Motor]

Supposing the cylinder to be rotated to the position marked O, the circuit may be traced from the positive terminal of the battery U, as follows: To contact spring E, to strip of brass L, to strip of brass M, to contact spring F, through the field windings VV, to contact spring D, to strip of brass K, to strip of brass J, to contact spring C, through resistance W and Y, to armature Z, through armature to the negative terminal of the battery. Moving the cylinder to the position P merely cuts out the resistance W, and to the position Q, cuts out the remaining resistance Y. The direction of the current through the armature and series field, for all positions of the cylinder to the left, is indicated by the full-line arrows. Moving the controller to the positions marked R, S, and T, will result in the same changes in circuit connections, as in the previous case, except the direction of the current in the series field windings will be reversed.

Upper-End View of the Controller, Showing the Manner of Attaching the Springs]

The construction of the controller may be carried out as follows: Obtain a cylindrical piece of wood, 1³⁄₄ in. in diameter and 3¹⁄₈ in. long, preferably hard wood. Turn one end of this cylinder down to a diameter of ¹⁄₂ in., and drill a ¹⁄₄-in. hole through its center from end to end. Divide the circumference of the small-diameter portion into eight equal parts and drive a small nail into the cylinder at each division point, the nail being placed in the center of the surface lengthwise and perpendicular to the axis of the cylinder. Cut off all the nail heads so that the outer ends of the nails extend even with the surface of the outer, or large-size, cylinder. Divide the large part into eight equal parts so that the division points will be midway between the ends of the nails, and draw lines the full length of the cylinder on these points. Divide the cylinder lengthwise into seven equal parts and draw a line around it at each division point. Cut some ¹⁄₈-in. strips from thin sheet brass and mount them on the cylinder to correspond to those shown in Fig. 1. Any one of the vertical division lines drawn on the cylinder may be taken as the neutral point. The pieces may be mounted by bending the ends over and sharpening them so that they can be driven into the wood. The various strips of brass should be connected electrically, as shown by the heavy lines in Fig. 1, but these connections must all be made so that they will not extend beyond the outer surface of the strips of brass.

A small rectangular frame is made, and the cylinder is mounted in a vertical position in it by means of a rod passing down through a hole in the top of the rectangle, through the hole in the cylinder and partly through the bottom of the rectangle. The upper part of the rod may be bent so as to form a handle. The rod must be fastened to the cylinder in some convenient way.

Make six flat springs similar to the one shown at A, Fig. 2, and mount them on the inside of the rectangle so that they will correspond in their vertical positions to the strips of brass on the cylinder. Six small binding posts mounted on the outside of the box and connected to these springs serve to make the external connections, and they should be marked so that they may be easily identified.

A flat spring, ¹⁄₄ in. wide, is made similar to the one shown at B, Fig. 2. Mount this spring on the inside of the rectangle so it will mesh with the ends of the nails in the small part of the cylinder. The action of this spring is to make the cylinder stop at definite positions. The top of the case should be marked so that the position of the handle will indicate the position of the cylinder. Stops should also be provided so that the cylinder case cannot be turned all the way around.

Miniature Push Buttons

A very neat and workmanlike push button may be made in the following manner: Procure an unused tan-shoe eyelet with an opening about ³⁄₁₆ in. in diameter, and at the proper point drill a hole into the board in which the button is to be set. Force the eyelet in flush, using a little shellac to hold it in tightly. For the button proper, polish off and round one end of a piece of brass rod of a diameter that will move freely up and down in the eyelet. Solder a small piece of sheet brass across the lower end to keep it from coming out, then adjust and fasten on the two contact pieces, all as indicated in the sketch. The larger piece should be quite springy so as to bring the button back each time. The connections may be made by slipping the wires under the heads of the two wood screws that hold the contact pieces in place.

As every experimenter knows, it is almost impossible to drill a hole in the varnished base of an instrument without leaving a raw edge. Under such circumstances, when it is desired to make an opening for conducting cords, and the like, simply drill a hole with an ordinary drill and then set in a small shoe eyelet, which immediately presents a very finished appearance.

* * * * *

¶Vaseline, with a little powdered gum camphor added and heated over a
slow fire, makes an excellent rust preventive for tools.

A Quickly Made Toy Electric Motor

The illustration shows a small electric motor of such simple construction that it can be easily made from odds and ends to be found in any amateur workshop. Cut six strips, ¹⁄₂ in. wide and 3¹⁄₂ in. long, from an old tin can, and bend them together into a U-shape. This forms the magnet A. The outside piece should be a trifle longer than the others so that its ends can be turned over the other ends to keep them all in place. Screw this down on a small wood base. At one side of the wood base, fix an upright, B, and on top, a light wood bracket, C, to take the upper bearing of the motor. The shaft D is simply a wire nail with the head filed off and filed to a point. Drive it through a 1¹⁄₂-in. length of the same kind of material as used for the magnet. This forms the rotating armature E.

Make a slight indentation with a center punch, or strong nail, exactly in the center of the base portion of the magnet to take the lower end of the shaft. For the upper bearing file the end of a brass screw off flat and make a similar indentation with a center punch, or by a few turns of a small drill. This screw should be adjusted in the bracket until the shaft rotates freely with the armature just clearing the tips of the magnet. Wind about 40 turns of fairly thin cotton-covered copper wire--No. 24 or 36 gauge is suitable--around each limb of the magnet, first covering the latter with paper, to prevent the possibility of short-circuiting. The windings should be in opposite directions so that the connecting piece of the wire from one coil to the other passes across diagonally as shown in the illustration.

The brush F is formed by doubling up one of the free ends of the windings after removing the cotton covering and fixing it firmly with two screws to the side of the upright. After attaching, it should be bent until the outer end bears lightly on the shaft. Remove the shaft and at the point where the brush touched, file two flat surfaces on opposite sides of the nail in a direction at right angles to the longitudinal center line of the armature. On replacing the shaft the brush should be adjusted so that it makes contact twice in a revolution and remains clear at the flat portions. Connect up to a battery, one wire to the screw at the top of the motor and the other end to the open end of the windings. Give the armature a start and it will run at a terrific speed.--Contributed by Morris G. Miller, New Rochelle, N. Y.

Gauge for Woodwork

A convenient gauge can be quickly made by using a block of wood and an ordinary nail, or several nails for different widths can be placed in one block. Drive the nails straight into the block until the distance between the head and block is the required distance to be gauged. The rim of the nail head makes the mark as the block is drawn over the wood surface--Contributed by E. P. Haldeman, Balboa, Canal Zone.

BY JOHN D. ADAMS]

Where a high degree of accuracy is neither desired nor necessary, a very satisfactory ammeter may be made at the cost of a few cents, and without using hairsprings, permanent magnets, or other articles usually not at hand.

The actuating device consists of a small coil of coarse, insulated wire, with a bundle of soft-iron wires for a core, which attracts a curved, soft-iron, wedge-shaped armature. The moving system is so balanced that the armature will hang as illustrated when no current is passing. On account of its shape, the higher the armature rises, the more iron it presents to the influence of the magnet, and, on the other hand, the greater will be the effect of gravity. The advantage of this type of control is the elimination of the irregular readings of the scale, due to the law of inverse squares, that usually follow when any method depending upon a variable distance is used. Further, the readings can be had as desired by altering the taper of the armature, its thickness, or its distance from the magnet, and also by adding a small weight of nonmagnetic material at the bottom. As most commercial circuits supply alternating current, the friction of the bearings does not affect the readings, since the alternations set up a decided vibration in the entire moving system, thus eliminating static friction.

In view of the variations above referred to, it will be evident that it is not very essential of what dimensions the apparatus is made. The instrument that I use has a base measuring 2¹⁄₂ in. by 5 in. The coil is built on a tube of glued paper, and contains about 15 ft. of No. 16 gauge wire. The terminals consist of the brass bolts taken from discarded dry cells. A steel sewing needle serves as a shaft, and a piece of wire for the pointer. The various joints are made with soft solder, and suitable stops are provided to keep the armature from shifting laterally. In calibrating, a blank scale should be glued in position and as many 55-watt lamps as possible arranged so that they can be placed in the circuit, one at a time. On a 110-volt line, each lamp added will mark a half-ampere point. If a sufficient number of lamps to carry the scale high enough cannot be secured temporarily, a resistance of some 20 or 30 ohms should be placed in the circuit without any lamps. Note the reading in amperes on the scale thus far constructed, and then begin adding the lamps again, making a mark on the scale as each lamp is added. In this manner a scale may be built up sufficiently accurate for all practical purposes.

If two identical coils are made in place of one, the additional coil can be placed in parallel with the instrument as a shunt, thus doubling its capacity and making it necessary, of course, to multiply all readings by two.

Footstool

The material necessary for the footstool shown in the illustration is as follows:

2 end pieces, 1 by 10 by 15 in.

3 cross braces, 1 by 4 by 12 in.

2 end braces, ⁷⁄₈ by 4 by 8 in.

1 top board, ¹⁄₂ by 10 by 14 in.

1 piece of leather, 11 by 16 in.

Round-head wood screws and nails.

The two end pieces should be marked to a suitable pattern, and may be cut out with a scroll or coping saw, or, if these are not available, with a keyhole saw. The center opening should first be bored at one end and then cut out with the saw. The three long braces should be accurately squared and finished at the ends; the rigidity of the stool depending on this work. The seat consists of a box form with the open side down. The top is a ¹⁄₂-in. board, 8 in. wide by 12 in. long; the sides are formed by two of the long braces, and the ends are the short braces. This box is securely put together with nails, and then screwed in position with round-head wood screws so as to be flush with the top edge of the end pieces. The lower brace is secured in place with screws. In putting on the leather top, ¹⁄₂ in. should be turned under at each end, and 1¹⁄₂ in. brought down on each side. This will provide sufficient looseness to pad the seat properly. Large round-headed brass nails can be used, producing a neat appearance. The stool is then ready for a suitable stain or finish.--Contributed by Stanley B. Furbeck.

Stopper for a Bunghole

While we were filling our barrels at the cider mill it was discovered that one barrel had no stopper. This did not bother the cider-mill man, who took up a sound apple of about the dimensions or diameter of the bunghole and squeezed it in, tight as a cork, then shaved it off flush with the barrel staves. We started Home and rolled it around a great deal with the other barrels, yet it held as tightly as any wood stopper.--Contributed by A. A. Kelly, Frazer, Pa.

* * * * *

¶An open umbrella placed on the floor upside down makes an excellent
receptacle for catching dirt and plastering when installing electric
fixtures.

A Woven-Reed Footstool

BY CHARLES M. MILLER

[The various materials referred to in this article by number or size
were described in detail in an article on “A Reed Basket,” in the Boy
Mechanic, Book 2, page 257.]

Reed furniture has become very popular within the last few years, and the newer designs and methods have been so attractive as to place this constructive effort among the handicraft series of modern art. It is possible so to analyze, simplify, and illustrate this work as to make it feasible for amateurs, and at the same time there are possibilities which involve problems that may try the ability of the skilled workman. In other words, there are possibilities of progress in this kind of furniture making. There are places where careful weaving is the principal aim; again particular attention will be given to corners, or, perhaps, a nicety of modeling will be found necessary to bring out the proper curves involved.

Each piece of reed furniture has a framework, usually of dowels, but it may also be made of boards in such models as small tables, dressers, bedsteads, chests, etc. The board construction is more often covered with flat reed. In footstools there are both kinds of framework. The illustrations show the same parts marked with the same letters throughout the series of sketches.

The framework of the stool is shown in Fig. 1, in which the rails and posts are made of dowels, ³⁄₄ in. in diameter, and the braces of dowels, ⁵⁄₈ in. in diameter. It will be noticed that the posts extend to the top of the frame for strength in this manner of construction. If the rails rested on top of the post S, the nails would have to be driven into the end grain of the wood, which makes the strength depend entirely on the holding power of the nail in this position, as there is no binding of the upper part to the posts in the weaving. With the post extending to the top, the nail passes through the upper part of the post and into the end grain of the rails, and the rails are bound together horizontally by the weaving.

The material for the frame consists of the following dowel stock: two pieces for rails, ³⁄₄ in. by 14 in. long; two pieces for rails, ³⁄₄ in. by 9 in. long; four posts, ³⁄₄ in. by 7 in. long, and two braces, ⁵⁄₈ in. by 17 in. long. These pieces are shown in Fig. 2. If notches are cut with a small saw, a coping saw preferred, in the ends of each rail and in the braces, as shown in Fig. 3, they will fit to the posts better and make a stronger joint. While different makers use a finishing nail; a barbed or corrugated, nail; or a cemented, or glue-coated, nail, I find the best to be an ordinary 4-penny nail, which answers the purpose well. Do not drive the nail through the posts without first drilling a hole with a ¹⁄₁₆-in. drill. A small hand or breast drill will be needed for this work.

Before nailing the frame together, the holes for the spokes in weaving should be drilled in the rails. The spokes may be No. 4 and the weavers No. 3 reed. The No. 4 reed requires a ¹⁄₈-in. hole. The hole for the top and end side spokes may be combined, as shown in Fig. 4. The dotted lines show the vertical and horizontal diameters, and E the outside and F the inside of the rail, one hole being represented as sawed in two. The spokes for the top extend down and out at the ends, and each may be of one piece, 32 in. long. As there are no spokes at the top extending to the side pieces, short spokes must be inserted at the right time for the side weaving. The location of the holes in the side rails is shown in Fig. 2. The holes in the side rails may be drilled straight in the wood.

The pieces may now be nailed together to form the frame, as shown in Fig. 1. If the top of the side rails A are set about ¹⁄₁₆ in. below the tops of the posts, the weaving will be almost level, as the winding reed is thinner than the round reed. The braces D are halved at the center, on a slant, to bring their upper surfaces on a level when they are in place. The length of 17 in., as given in the material list, is not accurate, as sufficient length is given to allow the ends to be cut, in fitting them in place after the frame is assembled. The posts should stand vertical and square. Try the braces before nailing them in place, to see that they do not draw the frame out of shape.

The first operation in weaving is to cover the tops of the four posts, which is started as shown in Fig. 5. A short piece of winding reed, G, is first tacked in place. A round reed can be split if one is careful, in case winding reed cannot be obtained. Tacks used by shoemakers are just the thing for fastening these weavings in place. After fastening the weaving G in place, another, H, is put on in an opposite direction, whereupon J is fastened on the same as G, and so on, until the post is covered, as shown in Fig. 6. Perhaps a better way to cover the posts would be to tack all eight pieces on the post part C, and then weave them down together. It may not be necessary to tack them all on the rails.

After the corners are all covered, the end rails B are wound with the winding reed, the start being shown in Fig. 7, where the frame is shown in an inverted position. The reed is tacked, at K, to the side rail, and whenever the winding comes to a hole, a pencil mark is made to locate the hole later. This mark is shown at L. When the two end rails are wound, push a bodkin, or other steel point, in between the windings where the marks are located, to make way for the insertion of the spokes. It may appear to an observer that the spokes could be put in before the winding, but the winding cannot be properly done after the spokes have been inserted, as the windings would separate too much around them. The hole must be opened up through to the opposite side of the rail. Single spokes go through the rail, and they are only put through one end rail at first, as the weaving is much easier with one end of the spokes free, but, of course, they must be inserted in the other end before the weaving gets within 2 or 3 in. of that end. An extra spoke is inserted beside each spoke, as the weaving proceeds and after a strip has been woven ³⁄₄ in. wide. These short spokes are cut just long enough to fit in between the end rails. The weaving is done with a single weaver, and it is passed over and under double spokes as if they were one. When the weaver comes to the side rail, it is wound twice around the rail, to take up the space for the two strands across. If the weaver does not go twice around the side rails each time, either the weaving will take a curve or the side winding will be loose. The starting of the weaving is shown in Fig. 8, where the extra spokes are inserted along the side of each spoke that runs through the end rails.

After the spokes have been inserted in the opposite end rail and the weaving in the top completed, the braces and posts should be wound. Where the braces D connect to the posts C, three strips of the winding reed are passed around the post and tacked on both sides of the braces, as shown at M, Fig. 9. Where the braces cross, the winding passes around both pieces for a short distance, as shown at N. It is quite appropriate to use the brass caps O on this model, but on many stools their use has been discontinued and the winding continues down to within ¹⁄₈ in. of the bottom of the post. In case the brass cap cannot be obtained, the winding may be used also on this model.

FIG. 2

FIG. 3

FIG. 5

FIG. 6

FIG. 4

FIG. 7

FIG. 8

FIG. 9

Details of the Dowel Pieces, Showing Dimensions for Drilling the Holes to Admit the Spokes of Reed, Manner of Building the Framework, and How the Top is Woven]

The side weaving is called the apron, and in this case the pairing weave is used. The short spokes will have to be inserted in the under side of the side rails, and the extra spokes are added after the weaving is started and a small strip woven. The pairing weave is shown in Figs. 10, 11, and 12. The two weavers are represented by the letters P and Q. The weaver P passes back of spoke T and out between T and U. The weaver Q is then used in the same manner, and so on, around the stool. When the post is approached the weaver that comes out between the last spoke and the post is passed around the post and in behind the next spoke on the other side. It will be seen in the pairing weave that the weaver behind is always thrown over the other weaver. This gives the appearance of a rope twist to the weaving, and also cinches it to the spokes and prevents slipping. Always pass the one weaver around the post twice to take up the space for the one that cuts across the corner. The weaving of the sides or apron is done with the object turned upside down, where it is in a good position for finishing off, which is sometimes called breaking down.

If the weaving has been carried far enough, the extra spokes are cut off even with the weaving, and the breaking down may be done as follows: The spoke R, Fig. 13, is shown turned down back of the spoke S, and S back of T and out. The spoke R, as shown in Fig. 14, is back of S, in front of T, back of U, and out between U and V, but as R is brought out, the spoke T is brought down back and parallel with R. Likewise the spoke S passes back of V, and U is brought down with it. The spoke T is brought back of W and V is brought down back of it. The short end of R is inserted under the roll, between the roll and the weaving, and is left extending on the inside. If it is too long, it can be cut off close to the inside of the weaving. In Fig. 15, all the short ends are shown brought through to the back as far as the weaving is illustrated. At the corners, the posts are used as spokes. To finish the roll, the spokes will have to be inserted through the roll, to correspond with the rest of it; hence, the beginning of the roll should be left loose, as in Fig. 13.

FIG. 11

FIG. 15

FIG. 12

FIG. 13

FIG. 14

The Weaving of the Apron is Done in the Same Manner as in Making a Basket, with the Break Down to Form the Edge]

In weaving, the weavers should be kept wet, but not the spokes. Do not put the reed in water and leave it for any length of time, as it will become discolored. About 15 minutes will be sufficient to make the reed pliable, then it is best to have a sponge and bucket of water at hand, to dampen long weavers frequently by drawing the reed across the wet sponge. Besides being more workable, the wet reed, held in place until dry, stays curved in the form woven much better. Some workmen leave the reed in water for a long time and depend on bleaching to whiten it, but so much of the bleached work looks like a poor job of painting that it is much better to keep it white from the start. In case bleaching is found necessary, a little chloride of lime in water makes a good bleacher. Avoid making the solution too strong. It should be put on with a brush, so as to get it into the interstices of the weaving, whereupon the work is placed in the sunshine to dry.

Any kind of reed used will have some of the small hairlike fibers sticking out after the weaving is complete, and this should be singed off with a gas flame. A blowtorch is good for this purpose. Be careful not to scorch the weaving.

A Homemade Ellipsograph

BY J. A. SHELLY

The instrument illustrated was designed to take the place of the two nails and a piece of string for drawing ellipses of different sizes. It is made of hard wood, preferably maple or beech, and consists of a bar with one fixed and one sliding head, the latter having a wedge clamp to hold it at any point desired on the bar.

In the ends of the heads are driven two coarse needles that have been broken off about ⁵⁄₈ in. from the eye end. These ends should be placed ¹⁄₈ in. from the inside of each head and the same distance from the bottom, and driven in until the eyes are each ¹⁄₈ in. from the surface. A piece of linen thread is run through the eye of the needle that is in the end of the sliding head and knotted to prevent its pulling out, and the free end is run through the needle eye on the fixed head. The thumb tack in the fixed head is to secure the free end of the thread. The tack is driven in at an angle so that one edge sticks up enough to allow the thread to be pulled under it.

To operate the ellipsograph lay out the length of the major axis on a center line, then bisect the distance between these points and erect a perpendicular. On this line lay off half the minor axis, measuring from the center line; then from this point locate the foci by setting the dividers to half the major axis and scribing arcs of circles to cut the center line. Set the heads of the instrument so that the projecting needle ends will be the same distance apart as the foci, and clamp the sliding head with the wedge. Set the instrument so that the needle eyes will be exactly over the points where the foci are on the center line. A pencil, with a little groove filed ¹⁄₈ in. from the point, for the thread to run in, is set to half the minor axis and the thread is pulled taut and secured by the thumb tack. The pencil should be held perfectly perpendicular while scribing the line. The instrument must be reversed to draw the other half of the ellipse.