Chapter XXVIII: Part II: Construction (5)

To use this instrument in measuring larger currents than it will safely carry, connect it in parallel with another resistance which will carry the larger part of the total current. The galvanometer can be calibrated with this resistance, which is known as a shunt.

How to Make Advertising Lantern Slides

Procure some old discarded photographic films and remove the gelatin coating by soaking them in hot water. When dry, write the desired words on the thin celluloid and place it between two pieces of glass, lantern-slide size, and bind them as in making a lantern slide.

With the use of a carbon paper a very nice slide can be made by writing the words on a typewriter, and it will serve the purpose of an expensive announcement slide.--Contributed by F. P. Dickover, Atkinson, Neb.

Utilizing Old Brush Handles

The handle cut from an old dusting brush, fitted with the brass end of a shotgun shell, makes a first-class tool handle. The handle is cut off at A and the wood cut down to fit tightly into the brass shell.--Contributed by James M. Kane, Doylestown, Pa.

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Tincture-of-iodine stains may be removed from clothing
or the skin by using strong ammonia water.

Preserving Paints and Pastes

White lead, thick shellac, and pastes that are used occasionally may be preserved by laying a piece of leather over the exposed surface. When these materials are kept in cans, cut a piece of leather from the upper of a heavy boot of such a size that it will drop freely into the container. Form a handle on the leather disk by driving a nail through its center from the under side. Press the disk down smoothly over the surface of the contents and a thin film of oil will soon form over the disk, effectually excluding the air. A loose cover is placed over the container, to keep out dust.--Contributed by Luther McKnight, Colorado City, Col.

A Burner for Soldering Small Work

As it was necessary for me to solder the joints of fine wires on electrical instruments, and other small work, I found myself in need of a blowpipe that gave a small but very hot and easily directed flame, was automatic in its operation and required no blast. I tried an ordinary acetylene burner on coal or city gas, and found it gave an intensely hot, nonluminous flame, due to the forced draft of air through the small holes. This flame will melt silver, copper and, also, silver solder. Its great advantage lies in the fact that it may be used for sweating together small articles rapidly and with great neatness. I always keep this blowpipe burning, as the gas it consumes is very small, and the burner is kept within easy reach by using a hanger, as shown in the illustration.

A single jet of flame is obtained by stopping up one of the tips, which is very useful in many ways. This flame may contain a small luminous spot on some city gas, but it does not interfere with the heat.--Contributed by Arthur Worischek, New York City.

A Safety-Match-Box Holder

A holder, as well as a tray, for safety matches can be made from any ordinary tobacco can. The metal on one side is cut as shown and the pieces bent up to form standards for holding the match box in an upright position. The openings left where the metal was raised are used for dropping the burned matches into the box. The hinged cover is used for emptying the tray.--Contributed by David B. Lutz, E. St. Louis, Ill.

Removing Ink Stains from Book Leaves

When the leaves of a book are accidentally stained with ink it can be removed quite readily by the following process: After removing as much of the ink as possible with a camel's-hair brush dipped in water, soak the stained parts in a solution of oxalate of potash, or better still, oxalic acid. This will remove all the ink. Treat again with water, as before, so that when it dries out no salt will appear on the paper. This process does not affect printer's ink.--Contributed by S. G. Thompson, Owensboro, Ky.

A Needle-Spray Nozzle

To make a needle-spray nozzle, either insert a 22-caliber cartridge in a small tube, or place a 45-caliber shell over the end of the tube and solder it in place. The end is perforated to make one or more small holes, as desired.

How to Make an Electrotype Stamp

The method described in the following produces a very good metal stamp for any name, initial, drawing, etc.

Procure a smooth and perfectly level sheet of brass about 1/16 in. thick and about 3 by 4 in. in size. Nickelplate the brass so that the copper deposit will not stick to it. If a small plating outfit is not at hand the piece may be plated at a local plating works for a nominal price. Dip the plate in melted paraffin until the coating is about 1/16 in. thick and see that no metal is exposed. Drill a hole in one corner and attach a wire.

Draw the letters or sketch desired, using a metal stylus having a sharp point, taking care to make the lines scratched in the wax clean and open to the surface of the metal (Fig. 1).

A large open-mouthed bottle or glass tank will be required for the plating solution, which is made by dissolving copper sulphate in water until the solution is saturated with the sulphate and then adding a few drops of sulphuric acid. Immerse the plate in the solution as shown in Fig. 2 and connect with the zinc pole of the battery. Put a piece of pure copper in on the opposite side of the jar and connect with the carbon pole of the battery, using care in each case to keep the connection of the wire and the upper part of the plate above the surface. One or two dry cells will be sufficient. If the current is right, the deposit on the waxed plate will be a flesh pink; if too strong, it will be a dirty brick color and the plate will have to be washed and the current reduced. When the desired thickness of metal is deposited, remove the plate and pour boiling water on the back. This will remove the thin copper shell and the nickeled plate may be laid away for future use.

Procure a flat pan and after placing the shell in it, face down, sprinkle a little resin or soldering flux on the back. Lay three or four sheets of the lead from tea packages on the back of the shell and heat it over a spirit lamp or on the stove until the lead melts and runs into the crevices on the back of the copper, thus making it solid and suitable for mounting. Mount as shown in Fig. 3 with small brass screws and after polishing the surface to remove dirt, etc., the stamp is ready for use.

An ordinary stamp pad will do for inking, but the best ink to use is printer's slightly thinned, as the ordinary rubber stamp ink is not suitable for a metal stamp.--Contributed by S. V. Cooke, Hamilton, Ont.

A Cover for a Bottle

If a glass medicine bottle is to be carried constantly in the pocket, it is best to cover it with leather or rubber. The sketch shows how to cut the pattern so that it will fit a square bottle. The bottle is placed on the leather, or a piece of paper as a pattern, and the outlines marked upon it. The leather or paper is then folded over four times and cut out as shown. This cover will prevent the glass from being scattered in the pocket should the bottle be accidentally broken. It always provides a means of distinguishing it from other bottles of the same type and size.--Contributed by James M. Kane, Doylestown, Pa.

Boring a Long Hole

The usual method of boring a hole through a piece of wood longer than the bit is to bore from each end. To make the hole straight by this method, split the wood or saw it in halves, then make a knife kerf in both pieces on a center line of the hole and glue the pieces together. The spur of the bit will follow the kerf from either end, and the result will be a meeting of the holes, almost perfectly in the center.--Contributed by Ernest J. Dickert, Niagara Falls, N. Y.

Covering for a Gas-Stove Top

While frying or cooking on a gas stove the grease will spatter over the top and make the cleaning rather difficult, especially where there are many crevices. A simple method of avoiding this trouble is to place a paper over the top of the stove, with round holes cut out for each burner a little larger than the pots and pans used in the cooking. This will keep the stove very clean with a minimum of bother. A paper cut to fit the under pan will keep that part clean.--Contributed by S. F. Warner, East Orange, N. J.

Homemade Skis

Not having a bent board suitable for a pair of skis, I proceeded to make the skis in the following manner: A cheese box was procured and two pieces cut out of the side, each 15 in. long and 3 in. wide. These were used for the upturned ends and two boards, 6 ft. long and 3 in. wide, served as the runners. A notch, 4 in. long and 1/8 in. deep, was cut in one end of each board to receive one end of the thin curved pieces cut from the cheese box, which were fastened with screws. The upper end of each thin piece was cut to a point.

A piece for the foot, 10 in. long and 3 in. wide, with a notch 1 in. wide and 1/4 in. deep, was fastened in the center of the runner. A strap is run through the notch for holding the ski to the foot--Contributed by Henry Meuse, Reading, Mass.

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To remove iron rust or ink stains from cloth, use a
warm solution of oxalic acid with a few crystals of
citric acid added. Repeat the washings until the stain
is removed.

How to Make a Dry Cell

The containing vessel for the cell should be made from sheet zinc. It should be cylindrical in form, approximately 2-1/2 in. in diameter and 6 in. long. This vessel is to form the negative terminal of the cell and a suitable connecting device, similar to the one shown in the sketch, should be provided and securely fastened to the upper edge of the vessel. The vessel should be lined with some heavy blotting paper, both sides and bottom.

Place into a glass jar a small quantity of chloride-of-zinc crystals, and pour over them 1/2 pt. of distilled water. Allow the crystals to dissolve at least one-half hour. If the crystals all dissolve, add more until some remain in the bottom of the jar, or until the liquid is saturated. Pour off the solution and dilute it by adding an equal part of distilled water. Add to this solution sal ammoniac, in the proportion of 1 lb. of sal ammoniac to every 2 qt. of liquid. Fill the dry-cell vessel with this solution and allow it to remain until the blotting paper is completely saturated.

Obtain a good size electric-light carbon, about 5/8 in. in diameter, and file one end down as shown. Drill a hole through the carbon and mount a terminal.

Make a mixture of equal parts of finely powdered carbon and manganese dioxide of sufficient amount to almost fill the vessel. Add to this mixture some of the solution and thoroughly mix them. Continue adding solution until a thick paste is formed.

Pour the solution out of the vessel and allow the latter to drain for a few minutes in an inverted position. Place the carbon rod in the center of the vessel and pack the paste down around it, being careful not to move the carbon rod from its central position. The vessel should be filled with the paste to within about 5/8 in. of the top. The lower end of the carbon rod should not be nearer the bottom of the vessel than 1/2 in. Over the top of the paste place a mixture of equal parts sand and fine sawdust and then, over this, a layer of pitch, which acts as a seal for the cell. A layer of blotting paper should be placed between the sand-sawdust mixture and the carbon-manganese mixture. The side lining of the vessel should be turned in before the sand-sawdust mixture is placed in the top of the cell. The outside of the cell should be covered with some heavy pasteboard, which will serve to insulate the negative terminal from the surface upon which the cell rests.

A Hose-Nozzle Handle

A handle for a garden-hose nozzle is easily made of a piece of wire and the wooden part of a package carrier. The wire is bent to receive the hose at A, and, after the handle is slipped on, the other end is formed to fit tightly over the brass nozzle at B. The hose nozzle can be easily carried with the handle, which will keep the hand dry.--Contributed by F. G. Marbach, Cleveland, O.

Guide for Cutting Mortises

After spending considerable time in cutting one mortise in a piece to make the settee described in a recent issue of Popular Mechanics Magazine, I devised the plan shown in the sketch which enabled me to cut all the mortises required in the time that I cut one in the ordinary manner. Two metal plates, one of which is shown in the sketch, having a perfectly straight edge, are clamped on the piece with the straight edge on the line of the mortise. A hacksaw is applied through holes bored at the ends and a cut sawed along against the metal edges.--Contributed by George Gluck, Pittsburgh, Pennsylvania.

Insect-Proof Poultry Roost

To protect the poultry from mites and other insects while roosting, I constructed a roost hanger, as shown, with oil cups made of empty shoe-polish cans. The cover of the box was nailed to the roost and the bottom, for holding the oil, on top of the roost support. A large nail was driven through the support from the under side and through the center of the can bottom, so that about 1-1/4 in. projected above the latter.

The can cover was perforated in the center and a hole, about 1/2 in. deep, was drilled in the roost so that the end of the nail would easily slip into it. The bottom of the can was filled with a mixture of kerosene, vaseline and carbolic acid and the roost set in place. Both ends of each roost are fixed in the same way. This makes it impossible for any insects to get on the roost.--Contributed by Rudolph Netzeband, St. Louis, Mo.

To Prevent Shade Rollers from Unwinding

Obtain a stick for the hem on the lower end of the shade that is 2 in. longer than the shade is wide. Place two small wood screws in the window casing below the shade roller in such a position that they will catch the ends of the stick when the shade is raised to the top.--Contributed by Harry E. Kay, Ossining, N. Y.

A Screen and Storm-Door Cushion

A good cushion that will prevent a spring door from slamming can be made out of material cut from an old rubber boot or, better still, from an old hollow rubber ball. Three strips of heavy rubber, 1-1/4 in. long and 3/8 in. wide, are cut and each fastened with two tacks so that the center will make a hump, as shown in the sketch. One cushion is fastened near the top, one near the bottom, and one in the center, in the rabbet of the door frame.--Contributed by D. Andrew McComb, Toledo, O.

Repairing a Coaster Brake

Anyone having a bicycle coaster brake that is apparently useless because it will not brake, can easily repair it in the following manner: Remove the inner hub by unscrewing the cones and insert a piece of clock spring, about the same width as the brake shell and almost as long as its inside periphery. Replace the parts and the repair will render the brake quite as efficient as a new one. The spring serves as a braking surface for the expanding steel shoes of the brake.--Contributed by Heber H. Clewett, Pomona, Cal.

Flypaper Holder

The ordinary method of using sticky flypaper is quite annoying, as it cannot be easily removed from anything that may come in contact with its sticky surface. The best way to avoid this trouble is to make a holder for the paper, and one can be constructed of a piece of wire and a metal cover taken from a jelly glass. The wire is threaded at one end on which the cover is clamped between two nuts. The upper end of the wire is shaped into a hook for hanging it wherever desired. The paper is rolled with the sticky side out and tied with strings, then slipped over the wire and set into the inverted cover. The cover prevents any of the sticky substance from dripping onto the floor and the wire holds it from being blown about the room.--Contributed by Percy de Romtra, Cape May Point, N. J.

A Fish Rake

The fish rake can be made in any size, for minnows or salmon, but it is especially adapted for fish that run in schools, like smelt, herring and minnows. Procure a piece of wood, 7 ft. long, 4 in. wide and 7/8 in. thick, and make a handle 3 ft. long on one end. Dress the other end to an edge, rip off a 1-in. strip and drill holes to receive nails or pieces of wire from the back, through the edge, and projecting about 4 in. The strip is then replaced and fastened with screws. The handle can be cut from the blade and jointed by using tubing. This makes it handy to take apart and pack.--Contributed by L. W. Pedrose, Seattle, Wash.

To Harden Small Blocks of Wood

Small blocks of wood can be hardened so that they will not split so easily when small screws are inserted by boiling them in olive oil for about 10 minutes. The olive oil can be kept for future use. If it is desired to waterproof the blocks after hardening them, they should be placed in melted paraffin and allowed to cool in the solution. This gives the block of wood a good appearance and makes it nonabrasive and waterproof.

Homemade Clothesline Reel

It is much better to make a small reel, like the one shown, for a clothesline than to wind the line on the arm, the usual method of getting it into shape for putting away.

The reel consists of two strips of wood, 16 in. long, 3 in. wide and 7/8 in. thick. These are joined together with two pieces of broom handle, allowing a space of 9 in. between the sides and an extending handle of 5 in. on opposite sides, as shown.--Contributed by Bert Longabaugh, Davenport, Iowa.

Gear-Cutting Machine

Perhaps the last thing that would be thought within range of the amateur who lacks a full equipment of machinery is the cutting of gear wheels. The device shown in the sketch is very practical, and, with the most ordinary assortment of iron-working tools, will serve to turn out an accurate gear.

No system of supports is shown, as they are easily supplied. A flat, square board, B, as large as can be obtained--2 ft. on a side being the safest minimum--is used for a dial. A sheet of paper is pasted over the entire board and a large circle drawn on it. This circle is divided into as many parts as there are to be teeth in the gear. A depression is made with a prick punch at each division. A shaft, C, is run through the center, to which an arm, A, is firmly attached. A nail, N, is placed at the end of the arm so that the point can enter each of the punch marks on the periphery or circumference of the circle. A blank wheel, W, is attached to the shaft C, in the position shown, and resting on the iron plate or strap F. A cutting tool, D, works up and down in a slot in F. This cutter is held away from the blank wheel by the spring S, and moved up to it by the screw G, acting through the sliding member H. A stove bolt may be used for G, with the nut firmly fastened to the strap F. The cutter is actuated with a handle E, whose motion is limited by the pegs as shown. In Fig. 2 is shown a top view of the strap E, with a cross section of the cutter and the slot in which it works.

The operation of the mechanism is as follows: With the blank wheel in place set the nail N in one of the punch marks and move the handle E downward. This will make a slight cut on the wheel. Then give the screw G a turn or two, which will make the cutter take a deeper bite, and push the handle down again. This operation is repeated, screwing G constantly deeper, until it is stopped by the locknut J, which regulates the depth of the cut. Move the nail N to the next punch mark and repeat. The operations are very quickly performed and the circle will be closed almost before you know it.

There are several points to be observed. The accuracy depends upon three things. First, the slot through which the cutter passes must be tight-fitting, even at the expense of working hard. Second, the shaft C must fit tightly in the holes made for it through B and F, also the arm A must be firmly attached, the shaft being filed flat at the point of attachment. The blank wheel should be keyed on the shaft or securely fastened with a setscrew. Third, the nail N must enter the punch marks accurately. As the grinding circle is so much larger than the blank, any error here is greatly reduced in the finished wheel. Once in a punch mark the nail must not be allowed to slip until the tooth has been cut.

In practice, it will be found better, after each stroke of the handle, to give a quarter turn outward to the screw G, thus avoiding the scraping of the tool on the up stroke. The cutter can be made of any suitable steel with the cutting point ground to give whatever shape is desired for the tooth. The best shape for any particular purpose can be found by reference to a book on gears.

This cutter is adapted, of course, only to the softer metals. For experimental purposes a blank cast in type metal is excellent and will last as long probably as required. The mechanism here described will cut brass perfectly well and a gear made of this more durable metal will answer for a finished construction. Type-metal blanks commend themselves because they are so easily cast, any flame which will melt solder being sufficient, and the molds, of wood, plaster of Paris or any easily worked material, being quickly constructed.--Contributed by C. W. Nieman, New York City.

A Potato Peeler

The guard is made of a piece of wire about 1 in. shorter than the blade of an ordinary table knife. The ends of the wire are turned into a coil to resemble a coil spring with coils close together. Allow enough wire to project on one end to be flattened and pointed for an eye extractor.

When this device is placed on the knife, the contrivance works on the same principle as a spokeshave. The first setting peels the potato without any appreciable waste, the other setting may be as desired for cutting slices.--Contributed by H. W. Ravens, Seattle, Washington.

An Easy Way to Develop Roll Film

This is simply a different motion to the tiresome seesaw one usually employs when films are being developed. In wetting them down previous to immersion in the developer, do not keep them in the water long enough to become limp, but remove them after a few quick dips, says Camera Craft, They will then retain some of their curling tendency, so that by taking one end in one hand and gradually lowering the film into the dish of developer and then raising it out of the dish, it will be found that the film will roll and unroll quite readily, much as one would let out or wind in a reel. This method will result in quicker development, because the roll is nearly always immersed in developer. The method necessitates using only one hand, making it possible to develop a second strip at the same time with the other. The illustration shows quite clearly just how the film will behave.

A Shoe Hanger

An inexpensive shoe hanger can be made of a strip of tin, about 1/2 in. wide and as long as the space will permit. Cut notches along one edge and bend the tin and tack or screw it on a strip of board or to the inside of the closet door. The shoes are hung up by the heels with the toes down.--Contributed by C. R. Poole, Los Angeles, Cal.

How to Make a Small Vertical Drill

A small hand drill with a three-jaw chuck that will take the smallest drill can be purchased very reasonably. For ordinary work these drills do very well, but for comparatively deep holes, or when using long, slender drills, some sort of a stand should be made, if for no other reason, to avoid breaking the drills, which is almost invariably due to the side motion of the hand. There are other reasons, however, for making such a stand, and these lie in the fact that it is impossible to drill by hand at right angles with the surface of the metal, or to hold such a drill sufficiently steady to avoid widening the hole around the top.

As each make of hand drill will require a somewhat different form of stand, no detailed description need be given of the one illustrated. The principal point is to have the base and standard securely set at right angles to each other, and then provide a smoothly sliding piece to which the hand drill may be clamped. The edges on this slide and the corresponding guides should be planed off to an angle of 45 deg. One of the guides should be adjustable, which may be arranged by elongating the screw holes and placing small washers under the heads of the screws that hold this guide to the main standard.

A neat little hand drill, arranged in this manner and firmly secured to the bench, may also be used for finishing the ends of small shafts, either flat or pointed, for polishing screw heads, etc., to all of which it gives that workmanlike appearance that can only be had when things are polished with a true rotary motion.--Contributed by John D. Adams, Phoenix, Ariz.

Decorating Candles

Candles can be easily decorated by the following method: The designs can be selected from paper prints which are tightly wrapped around the candle with the design in contact with the wax. Strike a match and play the flame over the back of the paper. Allow time enough for the melted wax to harden and then remove the paper. The print will be transferred to the wax.

Select designs that are not larger than the circumference of the candle. A good impression of ink on thin paper works best.--Contributed by J. J. Kolar, Maywood, Ill.

Homemade Hacksaw Frame

A home workshop not having a complete set of tools may be supplied in many ways with tools made by the owner. The hacksaw frame illustrated is one of these. The frame is made of hard wood. The saw end is inserted in a slot sawed in the handle end, and a screw or small bolt holds it in place. The other end is equipped with a bolt having a sheet-metal head, as shown at A. The blade is kept from turning by a projection of the sheet metal which fits in a saw cut made in the frame.--Contributed by W. A. Henry, Galesburg, Ill.

Drill Press on an Ordinary Brace

As the greater part of the energy required for drilling metal by hand is used for feeding the drill, I made what I term a drill box in which the brace is held perfectly true and pressure is applied by a weight. The feed can be changed for the different metals and sizes of drills, also for drilling the hard outside of castings and relieving the drill for the softer body. The constant feed will cause the drill to turn out a long chip, and a number of holes may be drilled to a uniform depth by using the same feed and counting the turns of the brace handle.

To build the box, first find the dimensions of the brace, as shown in Fig. 1: the diameter of the head A, the clearance B from the top of the head to 1/4 in. above the top of the handle C, and the over-all length D when the longest drill is in the brace. Make a box having an inside length equal to the dimension D, plus whatever additional height may be necessary for the work. Make the inside width twice the distance C, plus 6 in. for clearance; and the inside depth the length C, plus one-half of the dimension A, plus 3 in. Use material 7/8 in. thick and nail the parts together to form a rectangular frame. Cut a piece of broomstick as long as the dimension B, and two pieces of wood as long as the inside width of the box and as wide as the dimension B. Cut two pieces 1/16 in. longer than the dimension A and as wide as the length B. Nail these latter pieces together as shown in Fig. 2, leaving a square space in the center. This frame is to be nailed inside of the top of the box flush with the front, but before doing so lay it on top of the box to determine where the center of the square space will come, and bore a hole, large enough for the round stick cut from the broom handle to slip through easily, then nail the frame on the under side of the top piece.

Procure a tough piece of wood, 1-1/2 in. square and long enough to project 2 in. over the right and 10 in. over the left side of the box top, and when in this position, locate the hole bored for the round stick and bore a hole in the square stick, 1/8 in. deep, to coincide with it. Place the head of the brace in the guide and push it up until it touches the top of the box and block it up in this position, then drop the round stick through the hole and rest it on the head of the brace. Place the socket in the lever over the top of the round stick. Make a loop, 8 in. long, of heavy wire and hang it over the right end of the lever and mark the box at the lower end of the loop. Turn in a large screw 1/2 in. below this mark allowing it to project enough to hook the loop under it. Remove the round stick and put a screw at the point the bottom of the loop reaches when the lever is flat on the top of the box. Another screw turned in between these two will be sufficient to hold the lever in position. Different-sized weights, of from 5 to 10 lb., are used on the lever, but for small drills the weight of the brace alone is sufficient.--Contributed by Maurice Coleman, W. Roxbury, Mass.

Homemade Picture-Frame Miter Box

Any person wishing to make a picture frame, or to cut down an old one, requires a miter box for that purpose, so that the molding may be properly held while sawing it, and also for nailing the corners together. I made a miter box, as shown, and found it to be just the thing for this purpose. It is built on a base similar to an overturned box, the saw guides being held on the ends of a piece, constructed as shown at A. Holes are cut in the top, as shown at B, for one of the guides and for the two wedges. Two pieces, C, are fastened with their outer edges at perfectly right angles on the top.

The frame parts are clamped against the pieces on top with the wedges driven in between the frame parts and the brackets DD. After cutting the frame parts they are tightly held in place while fastening them, in any manner desired.--Contributed by A. S. Thomas, Amherstburg, Can.

Tank-Development Methods Used in Tray Development

If there are a number of plates to be developed, place a rubber band, about 1/8 in. wide, around the ends of each plate and put them together in a tray. The bands keep the plates apart. The developer is made up as for a tank and poured over the plates, then another tray, or dark covering, is placed over the top. Allow this to stand, rocking the tray from time to time, the same length of time as is required for tank development.--Contributed by Earl R. Hastings, Corinth, Vermont.

A Pushmobile Racer for Ice

The pushmobile shown in the illustration takes the place of the one with rollers that is now so popular with the boys. The materials required, usually found about any home, consist of a foot board, 1 in. thick, 2-1/2 in. wide and 2 ft. long; two pieces of wood, each 3/4 in. thick, 2-1/2 in. wide and 9 in. long; one steering post, 1 in. thick, 1-1/2 in. wide and 30 in. long; one handle, 6 in. long; one small hinge; one carriage bolt, 1/2 in. in diameter and 2-1/2 in. long; two 1/2-in. washers; a few screws, and a pair of discarded ice skates.

One of the 3/4-in. thick pieces is fastened solidly to one end of the foot board with the ends flush. The other piece is swiveled with the bolt at the opposite or front end of the foot board so that at least one-half of the piece projects beyond the end. The steering post is hinged to the projecting end. The skates are fastened to the 3/4-in. pieces for runners. The manner of propelling the racer is the same as for the pushmobile.--Contributed by W. E. Crane, Cleveland, O.

Homemade Ellipsograph By Chelsea Curtis Fraser

An efficient ellipsograph is the only device that will make true ellipses of various sizes quickly, and such a machine is in demand on some classes of work in a drafting room. Its cost, however, is prohibitive where only few ellipses are to be drawn, but a person handy with tools can make an apparatus that will do the work as well as the most expensive instrument.

The completed ellipsograph, herein described, will appear as shown in Fig. 1. It consists of two main parts, the base and the arm. The former is a hardwood piece, A, Fig. 2, to the side center of which is attached another hardwood piece, B. This latter piece may be dovetailed into A, but an ordinary butt joint will suffice, as a one-piece base, C, also of hard wood, is glued to the bottom surfaces of the pieces A and B, thus securely holding them together. Before gluing, however, care must be taken to see that the piece B is exactly at right angles with the piece A. This can be done with a try-square. Dimensions are given in Fig. 2. The same letters are used throughout for the same parts.

A 1/16-in. groove, H, is cut out at the juncture of A and B, to admit the flange of the minor-axis swivel head. Another groove, J, is made along the longitudinal center of the piece B, to receive the spine of the major-axis swivel head. Sheet brass plates, D and E, are cut from 1/16-in. stock and attached to the top of the piece A with screws. The plates F and G are of the same material and fastened in a like manner to the upper surface of the piece B. All plates project slightly where they touch the groove borders, as shown. This is to provide a bearing for the projections on the sliding parts against metal instead of wood. A piece of thin celluloid or brass plate, K, is inserted in the bottom side of the base C so that the point will be exactly in line with the center groove J, and extend outward 1/8 in. This point indicates the center of all ellipses to be drawn. In the bottom of the base C, at each end, drive an ordinary pin and cut it off so that a part of it will project beyond the surface of the wood. These extending ends are pointed with a file, and serve to keep the instrument from slipping when in use.

The arm L is shown in Fig. 3. It is made of either maple or birch. Follow the dimensions given, cutting a slot through it longitudinally, as shown at M, narrower on the upper side than on the lower, the upper being 1/4 in. wide. An octagon-shaped piece of wood, N, 1/2 in. thick, is glued to the end, to give a good seating for the sleeve O, which is a piece of 1/2-in. solid-brass rod, 2 in. long, drilled to receive closely the pencil sheath. The latter, P, can be made from a section of brass tubing such as is used in a bicycle-pump valve. The upper end is notched to receive a rubber band, and an ordinary pencil can be cut down to fit closely into the other end. The piece O fits tightly in a hole bored through N and L.

The detail of the minor-axis swivel head is shown in Fig. 4. This swivel head consists of two pieces of brass, one, marked Q, being 3/8 in. square by 3/4 in. long and the other, R, 7/8 in. square by 1/2 in. long, with a notch cut out as shown. These parts, as well as the somewhat similar ones for the major-axis swivel head, can be cast cheaply, or block brass may be cut with a hacksaw and filed to the right shape. A shortened dry-cell screw, S, with washer, to fit a tapped hole drilled in the piece Q, serves to bind the head where desired on the arm. The flange T is a piece of 1/16-in. brass driven into a slot cut in the piece R. The piece R is pivoted to the piece Q, as shown, by means of a piece of wire nail which engages Q, by friction, the lower end being fitted with a washer and riveted loosely so that the parts will turn freely.

The major-axis swivel-head detail is shown in Fig. 5. The piece U is the same size as Q, Fig. 4, with its screw set a little farther forward to make room for the pivot V, which loosely joins U and W together. The pivot is made of a wire nail, riveted on both ends. The piece W is of brass, 1/2 in. thick, 3/4 in. wide and 7/8 in. long. The spine X is made just thick enough to pass freely in the groove J, Fig. 2. A screw taken from a discarded dry-battery cell is used to bind the head to the arm.

To operate the ellipsograph, draw a line, Y, Fig. 1, on the paper, which is to mark the major axis of the ellipse. About midway of its length make a point to represent the center. On the latter set the point K, Fig. 2, and adjust the bottom forward edge of the base C parallel with the line Y. Set the minor-axis swivel head at such a point on the arm L that, when the latter is directly on top of the piece B, the pencil will touch the paper at a distance from the center, marked by K, equal to half the minor axis of the proposed ellipse. To secure the major axis swing the arm until it is parallel with the piece A, leaving the major-axis swivel head unset, and set it when the pencil point has been adjusted to the proper major radius.

Grasp the arm with the right hand between the swivel heads and bearing down, swing the pencil end from right to left. The rubber band will keep it constantly on the paper with even pressure. When half of the ellipse is completed detach the rubber band and reverse the instrument to the opposite side of the longitudinal line Y and draw the other half in the same manner.

Protector Cap for a Chisel Handle

The ordinary chisel handle will soon split and break under the continuous blows of a mallet. A very good and inexpensive method of preventing this is to procure an ordinary patent bottle cap and place it on the end of the handle. It is advisable to shape the end of the handle like a bottle top in order to firmly hold the cap in place.--Contributed by Bert Verne, San Diego, Cal.

Sweeping Compound

A good sweeping compound may be made as follows: Mix 1/2 pt. of warm paraffin oil with 2 oz. of melted paraffin wax and add 2 oz. of artificial oil of sassafras. Then pour the mixture into 10 lb. of sawdust and work the whole thoroughly together. Add to this mixture 4 lb. of clean sand and 1/2 lb. of coarse salt. Each article mentioned is comparatively cheap, and the compound can be kept in an open container.--Contributed by Loren Ward, Des Moines, Iowa.

Freezing a Basin to a Chair

Fill a basin or pot half full of snow, and secretly put a handful of table salt in it and place the vessel on a chair or table, wetting the space where it is to be set. After holding the basin in place for about two minutes, continually stirring the contents, it will freeze to the chair so solidly that when the basin is lifted the chair will come along with it.

This experiment is quite interesting to an audience and can be performed at any assemblage with success. If the instructions are carried out closely, the trick will always succeed and the audience will consider it magic. Even if performed in a warm room, the combination of snow and salt will reduce the temperature below the freezing point where the bottom of the vessel comes in contact with the chair seat.--Contributed by Harry Slosower, Pittsburgh, Pa.

An Envelope and Stamp Moistener

A moistener for postage stamps or envelopes can be easily made from a screw-top jar. A strip of felt cut as wide as the jar is deep and made into a roll large enough to fit the neck of the jar serves as a wick. The metal top is perforated, and, after filling the jar with water, it is screwed into place. This makes a very inexpensive moistener for the library desk.

A Homemade Drill Press

An ordinary breast drill is used in the construction of this drill press, it being rigidly secured to a piece of oak, A, 2 in. square and 18 in. long, which is a sliding member on the pipe B. In attaching the breast drill to the wood, a bolt, having a hook on the head end, was used at the top, at C, and a stud at the bottom D. Pipe clips, EE, were attached on one side of the block to fit loosely over the pipe B. The vertical part of the pipe is supported by two horizontal pieces, FF, which are fastened to a post. A feed lever, G, is pivoted at the top of the vertical piece of oak A and fulcrumed on the post with a bolt through a slot, the extending end carrying a weight as a counterbalance. The illustration clearly shows the construction of this very useful drill press.--Contributed by W. A. Ready, Boston, Mass.

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A pair of bicycle trousers guards makes excellent
sleeve bands when the cuffs are turned back and rolled
above the elbows.

Arts-Crafts Leather Work By Mary C. Scovel