MEDICAL SOLDIERS of our Army are up against a big job in carrying on their work of mercy in the rapid tempo of modem mechanized war. How they are meeting the challenge with new methods and equipment is an interesting story—illustrated by comparisons with the methods and equipment of the last war.
A Vivid Imagination Gets a New Twist on Propellers
Has the Answer to a Puzzler, But Now Wants a Spectroscope Model
We Were Just Too Modest About That Midget Radio
This Inventor Is Flying High on Thin Air
More Power to His Binoculars! Can You Help Him?
A Cipher Exponent Comes Up With an Explanation
Another Home Chemist Wants to Experiment on The Japs
We'll Spot Those Wolves Even in Our Ships' Clothing
Wanted: an Answer to This Bounding-Ball Baffler
He Hoards History in Headlines
I AM sixteen years of age and have quite an imagination. In your “Readers Say” I have read many wild, but good, ideas which, with a few changes, could be made practical and useful to Uncle Sam. I wouldn’t be surprised if some day I should see a plane with my idea on it.
ENGLAND’S TRADITION of always being able to “muddle through” her difficulties is again indicated by the news that she has found a substitute source for vitamin A. Prior to the war, she found it in the usual places—tomatoes, oranges, and other fruits.
SPOT-WELDING ITS FIBERS GIVES IT GREAT STRENGTH AND RESISTANCE TO WATER
KENNETH M. SWEZEY
BY INTERLOCKING the fibers and “spotwelding” them to each other, industrial scientists now produce paper that is amazingly strong when wet—a property which permits it to compete in many uses with burlap and cloth, releasing these materials for more urgent war needs.
PARACHUTE JACKETS, replacing the conventional seat and chest packs, are advocated as less bulky, more comfortable for the wearer, and as a means of contributing extra warmth through a revised method of folding. The jackets are sleeveless, reach to the thighs, and have a built-in harness.
Gunners Sight on Real Planes, But Gun Shoots the Other Way in Antiaircraft Training Aid
FIRING live shells at real planes gives realistic practice to antiaircraft gunners, without danger to the friendly pilots, in a system devised by James C. Karnes of Buffalo, N. Y. The fire-control officer tracks the plane through the left eyepiece of a special binocular telescope, giving gun data that are exactly correct as to elevation but 180 degrees wrong as to horizontal direction.
"DARK ADAPTATION" SOLVES QUICK ADJUSTMENT TO NIGHT VISION
THREE METHODS BY WHICH FLYERS' VISION CAN BE QUICKLY ADAPTED TO NIGHT FLYING
DO YOU know how to see in the dark? New scientific tricks enable you to do it better, and more swiftly. If you step from the street into a dark movie theater, it will take several minutes to see your way around, and half an hour before your eyes’ “dark adaptation" is complete.
LOTS OF THINGS ARE MADE OF PLASTICS—BUT What are Plastics Made Of?
GOLD, THEY SAY, is where you find it. A man may discover it or he may miss it; either way he has nothing to do with creating it. Plastics are just the opposite. Plastics are what you make them. You can make them hard or soft, light or heavy, rigid or flexible, opaque or transparent.
MALARIA, which kills more than 3½ million persons every year, is an aerial blitz inflicted on man by the Anopheles mosquito. It has a higher sickness and death rate than any other disease. Tropical medicine, operating against it in its favorite haunts, the Orient and the tropics, has developed scientific methods of prevention and cure.
HEAT GIVES SYNTHETIC RUBBER BOUNCE IT NORMALLY LACKS
WHAT puts the bounce in rubber, or causes it to snap back when stretched, is a fascinating subject to science and industry alike. The solution may mean still better synthetic substitutes with the elasticity necessary for tires, tubes, balls, and hundreds of other rubber products.
— from “Victory Through, Air Power," by Major Alexander P. de Seversky
THIS IS THE YARDSTICK AGAINST WHICH OUR ARMY PLANES ARE TO BE JUDGED
What You'll Want to Know About Our Army Planes
P - 40 VERSUS ZERO: HOW THE BEST-KNOWN U. S. FIGHTER LINES UP WITH THE JAP MITSUBISHI
EVOLUTION OF A GREAT FIGHTER
The Mitchell (North American B-25) Has Made History in This War
The Marauder (Martin B-26) Used Torpedoes at Midway
THE SELF-SUFFICIENT FORTRESS NEEDS NO FIGHTER ESCORT
THE TRUTH ABOUT THE FLYING FORTRESS AND THE LANCASTER
THE BRITISH SCRAPPED THEIR OWN PLANE FOR THIS U. S. TYPE
THE P-51 FIRST U. S. PLANE BUILT FROM WAR INFORMATION
HERE ARE SOME OF THE JOBS OF THE LOW-FLYING MUSTANG
WILLIAM S. FRIEDMAN
ARMCHAIR AVIATORS, high-altitude radio commentators, and literary strategists have, in the last few months, managed to throw the public mind into a dither of doubt as to the value of our military aircraft. Their chief weapon has been comparison—the quotation of figures which have made some of our planes appear third-rate.
OF THE 40-odd species of scorpions found in the United States, two are dangerously virulent to man; their venom can, and frequently does, cause death. As far as is known, the lethal varieties of these eight-legged little monsters, which are not insects, are confined to Arizona, principally the southern half of the state, although recent reports indicate that a few, or perhaps a new species, live in Texas and California.
NATURE makes rubies and sapphires by fusing aluminum oxide in her own laboratory, the volcano, under terrific heat and pressure. Man can do the same job by dribbling aluminum oxide into an extremely hot flame formed by the union of oxygen and hydrogen, and catching the melted droplets on the end of a pointed stick.
A MODEL of the famous P-39 Airacobra, with workable cockpit controls that manipulate ailerons, rudder, and elevator in exactly the same manner as in the actual aircraft, is now in manufacture at a price within the reach of any aviation student.
PUMPS INSTEAD OF PROPELLERS provide power for the newest of the U. S. Coast Guard’s fire boats, eliminating the danger of propeller damage by floating debris. These new boats, 101 of which are being built for the Coast Guard by an engineering concern in Ohio, are each equipped with four pumps powerful enough to deliver 700 gallons of water a minute through the fire hose at the same time they are maneuvering the craft.
"SWAMP GLIDERS" like that in the photo at right form an important part of the Army’s “Navy” at Langley Field, Va., where they speed to the rescue of flyers forced down in marshy areas which are impassable for both land vehicles and ordinary boats.
Swinging Pendulum Weighs the Earth to Find Its Mass
PUTS THE EARTH ON THE SCALES
CHAMPION weigher of the earth, Dr. Paul R. Heyl of the National Bureau of Standards, has just rechecked his last figure of 1930 with improved apparatus and slightly greater precision. By timing the swings of a horizontal or torsion pendulum between two heavy cylinders of known mass, he and an associate, Peter Chrzanowski, measured the constant of gravitation, which scientists call “g” for short.
PLASTIC MASKS PROTECT WORKERS IN WAR PLANTS Eyes, throat, and lungs are shielded against flying particles of metal and dust by this mask fitted with clear plastic lenses and a plastic respirator that is packed with several different filters for as many types of fumes.
IODINE IN SEALED GLASS CAPSULES, protected by plastic tubes and tipped with compressed absorbent cotton, are part of the first-aid equipment of the men in our armed services. Pressure on the tube breaks the glass, allowing iodine to saturate the cotton swab for immediate treatment of wounds, as shown below.
AUTOMATIC DE-ICING OF PLANE WINGS is accomplished now through the use of an electronic ice indicator. The sensing element is a plastic disk—shown above installed on a test section of the leading edge of a wing— set flush so as not to disturb the airfoil and connected both with an indicator and the power-supply unit of the de-icing mechanism.
PHOSPHORESCENT PAINT for the rims of the many dials needed in the steering and fire control of a ship is being advocated by Westinghouse engineers for use by the Navy. Prime value of this kind of paint is that it glows under black-light radiations — and would continue to glow of its own accord for several hours after an enemy bomb or torpedo had knocked out the lighting system.
V-Mail Letters Are Reduced to 16-mm. Microfilm, Flown to . . . . . . Destination, Enlarged Back to Reading Size, and Distributed
FASTEST, surest, and most patriotic way for folks at home to communicate with their soldier relatives and friends overseas is through the V-mail system which has been in use by the Army Postal Service since last June. The operation involved is a comparatively simple one.
GAS and tire shortages are bringing back some of these eight American carriages, selected for POPULAR SCIENCE MONTHLY by William Brewster, famous carriage maker, from his prints at the Metropolitan Museum of Art. These are a buggy, brougham, phaeton (lady’s), stanhope phaeton (gentleman’s), station wagon, surrey, tandem cart, and victoria.
SCIENTISTS have estimated that the loudest sound that could be produced would not reach more than 190 decibels. New York’s super air-raid siren atop the RCA Building, when operating at full throttle, reaches a horn volume of 170 decibels, and can be heard over 50 miles away.
ELECTRONS, NATURE’S FUNDAMENTAL BUILDING BLOCKS, ARE WORKING NEW MIRACLES IN SCIENCE AND INDUSTRY
What Is an Electron?
MATTER IS MADE OF ELECTRONS, PROTONS, AND NEUTRONS
HOW ELECTRONS FORM CHEMICAL BONDS BETWEEN ATOMS
HOW ELECTRONS ARE PUT TO WORK IN A VACUUM TUBE
GRID ACTS AS SHUTTER CONTROLLING THE FLOW
AN ELECTRON is a subatomic particle of negative electricity so small that a billion billion billion would weigh less than an ounce. Singly, its power is insignificant; more than two million million million electrons must pass a given point in the filament of a 100-watt lamp each second in order to heat the lamp to normal brightness.
NEW MATERIALS, PLUS ECONOMICAL USE, EKE OUT OUR SUPPLY OF IMPORTED CORK
HINTS ON THE PROPER CARE AND HANDLING OF CORKS
TO GET LONGER USE IN THE KITCHEN AND LABORATORY
"THERE’S enough cork for two to five years, with more still coming in on neutral ships; no need to worry yet.” That’s what the cork experts say, but in times like these “enough” has a special meaning. There isn’t enough for unlimited civilian use.
TEN YEARS of mathematical calculation, following more than a year of extensive observation by astronomers of 15 countries, have established the distance from the earth to the center of the sun at 93,005,000 miles. The new determination, which replaces the previous best value of 92,900,000 miles, was obtained by methods basically similar to the triangulation used by mundane surveyors, and is accurate within 9,000 miles, an uncertainty which corresponds to the apparent breadth of a human hair at 10 miles.
SCALE models, accurately reproducing the appearance of principal types of German and American tanks, are helping to train U.S. soldiers in instant recognition of friendly and hostile armored vehicles. In the hurly-burly of a modern tank engagement, the lives of men and the outcome of battles may depend on split-second decisions as to whether mechanized units glimpsed fleetingly under varying conditions of distance and light belong to our own forces or to those of the enemy.
BIG BOMBS used by the Nazis have been reproduced by property men of Columbia Studios for exhibition in Los Angeles by the Office of Civilian Defense. The mammoth death dealer being embraced by the two girls in the photograph at the left is a replica of a 2,500-kilogram (about 5,500-pound) bomb nicknamed Max, which is said to be capable of demolishing buildings over an area six city blocks square.
THIS COMPACT GAS GUN is called the first self-firing, self-extinguishing acetylene torch to be put on the market. The trigger mechanism strikes a spark from a flint when pressed, causing the gun to blaze immediately. Small and easily maneuverable, this automatic torch is used for soldering, light brazing, and lead burning in cramped quarters.
A 200-TON BENDING PRESS has been especially designed and built to handle hydraulic pipe required in a variety of shapes by the war effort. Production experience has demonstrated that, because of the tremendous power of this machine, most pipes can be bent in it without preliminary heating or other special treatment.
FINISHING OF SMALL GEARS is facilitated by this new rapid-finishing machine, which operates by the crossed-axis principle of gear shaving. Designed for work on gears less than 4" in diameter and under 1" face width, the machine is especially handy in producing gears for instruments, control mechanisms, and other precision devices in which high accuracy must be combined with correct tooth formations.
MANY of the problems of administering first aid at the scene of war attacks or industrial accidents are lessened with the aid of this nurse’s kit, worn as a back pack that can be swung around to the front where it will serve as a handy instrument and medicine “table.”
How America has Developed the World's Best Automatic Weapons
YANKEE INVENTIVE GENIUS, PLUS THE LESSONS OF THE WAR, GIVE US THE LEAD IN THE ARMS THAT ARE MAKING HISTORY
.30 LIGHT MG.
.30 HEAVY MG.
EVOLUTION OF THE MACHINE GUN: FOUR STAGES IN ITS DEVELOPMENT
.50 LIGHT MG.
.50 AA MG.
BROWNING AUTOMATIC RIFLE
JOHN H. WALKER
AUTOMATIC weapons made history and changed the entire nature of warfare between 1914 and 1918. Autoarms are dominating the present war even more completely, and have undergone superb technological development, ranging in size from the toylike .25-caliber dress pistols worn by staff officers in some European armies up to bulky quick-firing antitank and antiaircraft guns of 40 or 50 millimeters.
CASTER, CAMBER, TOE-IN, AND TOE-OUT ALL CONTRIBUTE
WHY FRONT WHEELS TOE OUT FOR TURNING CORNERS.
SCHUYLER VAN DUYNE
WITH the first two-wheeled cart came the problem of steering geometry. If the wheels were not parallel, one or both would have to skid as the cart moved. It is a vastly more complicated task for geometricians to figure out the relative position of the four wheels of a modern automobile, with the front ones pivoted, with all on springs attached to a rigid frame, and with numerous other factors necessary to skidless operation to be considered.
1 WHITE PAINT ON THE GARAGE FLOOR will reflect light upward and be of immeasurable help the next time you have work to do on the underside of your automobile. One mechanic keeps calcimine in the garage, and paints a spot on the floor a little larger than the area covered by the car.
2 TO MAKE YOUR OWN RUBBER MALLET for a useful addition to the tool kit, slip a rubber tip from a crutch or cane over the face of a ball-peen or other hammer. This makes it unnecessary to carry more than one hammer in the kit. Rubber tips are available for a few cents at drug and ten-cent stores and at physicians’ supply houses.
3 A WOMAN'S PURSE that has been discarded will serve as a handy case for small tools. These pocketbooks, especially the plain, rectangular ones, will hold a surprising number of socket and straight wrenches, screw drivers, pliers, chisels, punches, files, and small hammers.
4 REVERSING THE HANDLE on the door next to the driver’s seat will often save tearing a coat pocket or sleeve when getting in or out of the car, or making hard turns such as in parking in close places. With the handle pointing toward the front, it is pulled back instead of being pushed down to unlatch the door.
5 SKID CHAINS GO ON WHEELS EASILY if one end is attached first to a piece of heavy wire, shaped as shown in the drawing, and the car backed over the chain until the two ends meet. Then it is a simple job to hook the ends together. Put the curved-wire tool through one of the chain-strap openings on the wheel, and remove it after the job has been completed.
6 FREEZING OF A CAR-DOOR LOCK can be prevented by forcing a small amount of alcohol into the keyhole with an eye dropper. If the lock is already frozen, thaw it first with the warmth of the hand or a match flame. Alcohol containing a rust inhibitor is preferable, and one application should last an entire winter.
7 A FISHING-ROD RACK under the roof of your car can be made in a few minutes with three pieces of stout elastic band and half a dozen safety pins. Pin two of the bands at one end so that the reels will fit between them, and then attach the third at the far end to allow about four inches of the rods to extend beyond it.
A BRUSH-ON COATING that promises to add to the life of your tires is the latest rubber-conservation device. A paintlike liquid, it penetrates the pores in the surface of the tires, and forms a tough, solid mass without lessening resilience.
GASOLINE IS PROTECTED from theft with this perforated tube that fits into the filler pipe of a tank and bars insertion of siphons. Its connecting spring wires snap it in place so that it can’t be removed during the life of the car. This lock is made so that it will fit any automobile tank.
DIM-OUT MASKS for driving at night in dimmed-out coastal areas are now available for motorists who do not want to paint their headlights black. The masks are really slip covers of black, water-repelling fabric, and contain small slots, as shown above, through which enough light for driving will reach the roadway.
A NEW STORAGE AID—this one for the outside of your car—is a sturdy kraft paper cover that fits completely over the top and sides of the body. This protects the finish from dirt, scratches, and other minor blemishes that occur in even good storage.
OLD Silas Barnstable drove his sedan into the Model Garage looking even more than usual like a shopworn bantam rooster. “Gosh dang it, Gus Wilson,” he snarled, “my clutch is out of whack again. ’Tain’t six months ago I paid good money for you to fix it.
SNOW and winter are a photographer’s paradise. Blue sky, crisp air, and trees sagging under heavy burdens; roof tops and church steeples white, fences and bridges encrusted, and brooks partly frozen; bundled-up passers-by—these are the rewards.
THIS COMPACT CAMERA CASE holds flash gun, spare batteries, reflector, and flash bulbs, in addition to a 35-mm. camera, which is locked in place. Measuring 7" by9½" by 5½", the case is constructed of three-ply wood, covered with tan leatherette, lined with maroon plush, and equipped with a carrying handle.
A NEW TITLING KIT made entirely of nonstrategic materials promises to aid home movie makers. A piece of felt stretched over a wood panel serves as the background. The letters and numbers have thin felt glued to their backs so that they adhere to the background wherever they are placed, much as two brushes will cling to one another if tightly pressed together.
FOR EXAMINING SLIDES, a new viewer has been designed of wholly wood and glass construction. It takes 35-mm. slides and is compact enough to fit into an accessory case or a coat pocket. Its lens, slide, and light source are so well balanced that pictures viewed through it appear to be three-dimensional.
DO THE extension outlets on your flash gun accommodate standard electric plugs? If not, you can use an extension by splicing it right into the synchronizer wire, thus equipping the synchronizer plug for double duty. Just splice a short length of wire to the synchronizer lead, and to the free end attach a female radio plug, which is smaller and lighter than standard 110volt plugs.
USING oil or grease on a camera is not advisable, but some lubrication on the bellows slide and the slide that locks the back will be found helpful. A good way to provide this is to use a lubricating stick made for taking out squeaks in auto-door hinges.
IF GREATER magnification is wanted without raising an enlarger higher from the easel, as in blowing up very small negatives, slip a portrait attachment over the enlarger lens. This shortens its focal length and increases the image size.
TO KEEP a fine point on your retouching pencil, place a folded sheet of fine sandpaper inside an envelope. Twist the pencil while holding the point from the outside. The scrapings will stay in the envelope.
Towel Rack Fastened to Bench Proves Handy in Darkroom
C. H. COLES
A RACK attached to your darkroom workbench will keep a towel always handy. This rack consists of a piece of wood 1" by 4" by 18", having a rounded top edge, fastened 2" from the bench with blocks 1" by 2" by 4". A strip 2" by 16" is cut out of the center of the rack to be used as a towel locking piece.
AN EASY way to give prints a professional-looking embossed border is to use two strips of heavy cardboard, such as mounting board, to guide the tool. These strips must be slightly longer than the picture, cut perfectly straight, and hinged together with gummed cloth, paper, or cellulose tape at one end.
A BRUSH-MOISTENING solution that makes color stick to glossy surfaces will help you in spotting photographs. It consists of one part 1-percent Aerosol or other wetting agent, three parts methanol, and six of water. Saturate your brush with this solution before taking up the water color.
IN THE process of keeping your home livable for the period of scarcity ahead . . . or of remodeling it to provide living quarters for war workers, if yours is a defense area ... or of providing an extra bedroom for your married daughter and her baby while her husband is in uniform, wall board seems almost to be item number one among necessary materials.
Poultry Watering Stand Built with Slatted Wooden Top
RAYMOND T. PARKHURST
BECAUSE wood must replace metal and wire wherever possible on the farm, the poultry and agricultural engineering departments of the Massachusetts State College, at Amherst, have devised a watering stand that dispenses with the usual wire top.
Model-Airplane Dope Conceals Scratches on Bicycle Frame
IF YOU leave scratches on your bicycle, the metal is likely to rust. However, scratches can easily be touched up by wrapping cellulose or adhesive tape around the frame about beyond each end of the damaged area and applying model-airplane dope of the right color.
THIS sturdy folding stepladder stool has several features that are not found in any other stool of its type. Built for long life and designed so that it will remain free from wobble, it should find favor with housewives in performing their usual tasks about the home.
YOU can no longer buy new lamp cord freely, and as it becomes more scarce it will be more and more difficult to operate electrical appliances. Lamp cord is really indispensable. The one certain way of making the cords you already have last for the duration is to take care of them.
BROUGHT up-to-date, this roller-skate scooter has convincing naval lines and is light enough for speedy “cruising.” The chassis consists of a 40" length of 1⅛" by 4" stock such as pine. It is pointed at the bow, rounded at the stern, and hollow between decks forward, with linoleum “planking.”
CAMELOT, the popular modern game invented by George S. Parker, suggests in its play no less than in its name the tournaments and wars of medieval times. Two opposing forces, each consisting of ten men and four knights, face each other in the middle of the field between their “castles”—the two starred squares at each end of the board.
Plaster of Paris casts should be left to dry for several weeks before being antiqued. Then give the surface a coat of white shellac. Let this dry and apply a second coat of shellac. Obtain a tube of artist’s burnt-umber oil paint and thin with turpentine until it flows readiy.
OLD upright pianos, no longer good for batting out martial airs, are going to drop out of the skies in quantity on Berlin and Tokio if a program developed by the Hoosier Home Workshop Club in Indianapolis, Ind., spreads to the rest of the country.
DIAMOND dressing tools, used for truing grinding wheels, leave the surface so smooth that for certain types of work it cuts too slowly and causes overheating. This difficulty can be overcome by using a mechanical dresser or star wheel—a tool consisting of a number of notched disks—to break away or open up the surface.
BICYCLE racers and other cyclists who take long bike trips know the advantages of having toe clips or rests on their pedals. The trouble is that most of the toe clips on the market are designed to fit on metal pedals, while the ordinary bike is equipped with large rubber-surfaced pedals.
Although less familiar than the customary plating metals, tin, iron, lead, cobalt, antimony, and arsenic are sometimes useful in special applications, such as for decorative work. Tin. This forms an excellent protective surface, particularly for iron and steel.
HEAT-REFLECTING RADIATOR SHIELDS, usually made of aluminum, are now available in efficient composition substitutes. Foil reflectors come in rolls of four sheets, enough for two average-sized radiators, at a cost of only a dollar a roll.
PREFABRICATED CABINET SHOWERS now on the market dispense almost entirely with critical metals. The model illustrated below is made of precast concrete and waterproofed fiber board, and comes fully equipped.
GALVANIZED ROOFING NAILS are conserved by a new “spot-welding” method (not illustrated) for the application of asphalt shingles, roll roofing, and the so-called “split-sheet” and built-up roofings. It was developed on the West Coast to meet the shortage of roofing nails.
HOLD-DOWN BRACKETS now on the market will prevent escape of light around the edges of ordinary window shades. They come complete with washers and nails and are fastened on the sill in such a position that they catch the folded-over hem of the shade when it is brought down a little farther than usual.
UTILITY KITS containing an assortment of screws with the recessed-head design, and special drivers to fit them, are now being sold in hardware stores. This new type of screw, in addition to being more decorative, eliminates the burring that mars slotted heads, prevents slipping, sets up tighter, and is self-centering, requiring the use of only one hand to start and drive.
A WEATHERSTRIP THRESHOLD made of unbreakable plastic, highly efficient as a fuel saver, can now be obtained in any length desired, complete with interlocking hook, nails, and screws. Its deep brown color blends with typical flooring materials and finishes, and under conditions of ordinary traffic its plastic composition is practically indestructible.
THIS NEW BULB, one of many varieties developed for blackout use, operates on only two watts and can be kept lit during a blackout even with unshaded windows. Dispensing with the filament wire used in bulbs of standard construction, it resembles the fluorescent type of lighting.
THE BLACKOUT SHADE shown at right is now available at low cost in many department and chain stores. It is made of heavy midnight-blue crepe fiber and is as easily installed as an ordinary window shade. In addition to being lightproof, the shade is impervious to fire unless water-soaked.
KITCHEN modernization is an old story, but war conditions have put a new obstacle in the way—and this provides an opportunity for the amateur woodworker to help himself. We cannot now go out and buy steel cabinets; even good wooden ones are comparatively hard to get.
REMEMBER the one-horse barn common in the days when Dobbin provided the family transportation? This toy barn may well awaken old memories in many of us— and what child won’t enjoy hitching and unhitching the horse, filling the hayloft, locking up for the night, and so forth?
This article is based upon one of a series of 16-mm. sound films prepared by the U. S. Office of Education for training war workers and distributed for the Government by Castle Films. For the machine-shop student or beginner, the value of these motion pictures cannot be overstated. They explain in the simplest and most graphic manner the operation of the standard tools and machines used in industry. Make every effort to see these films if they are being shown in your community or in the plant where you work. IF YOU were building a machine and accidentally bored a hole in a certain part .010" oversize, you could perhaps save the part from the scrap pile by turning the shaft or other piece that is to fit the hole also .010" oversize. However, if the shaft were to be made by another operator, working from a blueprint, he would presumably turn it to the size specified, and it would not fit.
Centering Work in Your Lathe to Get Surface Running True
J. S. MORREL
CENTERING finished bar stock or previously turned work so that the finished surface runs exactly true is virtually impossible by the usual punch-mark and center-bit method. It can easily be done as follows: Grip one end in the chuck and adjust it to run true.
Draftsmen Aided in Detailing by New Type Angle Guide
SPEED in drafting can be increased by using a guide with fixed angles on both sides of the vertical to draw small details such as hexagonal nuts, small polygons, and symbols. Ordinary triangles must be constantly lifted and reversed, but the handy all-purpose angle of which two types are shown above will draw 30-deg.
DRAFTSMEN who occasionally drop or mislay their instruments will find the magnetic holder shown at the left a real convenience and a timesaver when a rush job is to be turned out. It consists simply of a large horseshoe magnet (obtained from an old-style radio loud-speaker) clamped to a baseboard by a metal strip and two wood screws.
THE first home workshop to win the “M” award and the “Victory Fleet” pennant of the Maritime Commission for outstanding war production is that of William T. Morris, of Oceanside, Long Island, N. Y., a POPULAR SCIENCE subscriber. He was presented with these at his home by Rear Admiral H. L. Vickery, vice-chairman of the Maritime Commission, in the presence of Assistant Postmaster General Walter Myers and 2,000 neighbors.
HOMEMADE EQUIPMENT NEEDED IN QUANTITY BY RED CROSS WORKERS
CHARLES HENRY HUNT
THOUSANDS of women are working in the production rooms of Red Cross chapters making surgical dressings, gowns, kit bags, and other supplies for our armed forces. Simple equipment built by home craftsmen or school shops can render their task easier and increase production of these much-needed articles.
OFTEN temporary markings, such as dates of revision or quantity designations, are needed on blueprint tracings. Since ink erases badly from a tracing, these markings are usually made directly on the blueprint, but this is a nuisance if several copies are involved.
A LITTLE WOOD GOES A LONG WAY IN MAKING THESE TWO ATTRACTIVE PROJECTS DESIGNED BY ERNEST R. DEWALT
BREAKFAST SHELF. This decorative hanging unit makes it possible to group together the related dishes for breakfast for four persons. Not only does it save space, but the rack can be placed at whatever spot is most accessible in the kitchen.
MANY who have wished to make their own skis have hesitated because of the difficulty of bending solid tips. However, very satisfactory skis can be made by laminating the tips, and no boiling or heating is necessary with this type of construction.
SIMPLE METHOD OF SCALING OFF DIMENSIONS FROM ANY FIREARM
CARL G. ERICH
MEASURING a gun or pistol is a simple procedure. Once certain key points are fixed, a drawing can be made or a blank cut out for a whittled model. A yardstick, one or more try squares, and calipers are the only tools needed. Clamp or otherwise fasten a yardstick to the bench or table.
Finishing Nails Used to Bind Magazines into Neat, Serviceable Volumes
ATTRACTIVE, durably bound volumes, each containing three issues of POPULAR SCIENCE, may be made simply by nailing them together with 1" finishing nails. This method requires no press and is much easier than the conventional one, yet gives surprisingly neat results provided you are very careful to keep the magazines aligned.
Flat Steel Snaps on Ring Permit Keeping Keys in Groups
R. L. WHITMAN
ANY key ring can be fitted with flat key snaps bent from spring steel as shown at the right. These will allow even a good-sized bunch of keys to lie flat in the pocket. Furthermore, a group of two or three keys, such as automobile ignition, tank, and trunk keys, can be taken off the ring together and as easily replaced when no longer needed.
Platform Hooked on Ladder Rung Provides Secure Footing
ALLEN G. BROWN
A HANDY ladder platform may be made from two pieces of band iron, each 1/4" by 1¼" by 48", and a short board. Such a platform is safer and much more comfortable to stand on than ladder rungs, and is especially valuable when installing eaves troughs and the like, since it brings one alongside his work rather than underneath it.
GLASS COFFEE MAKERS now on the market will be of interest to housewives who cannot replace old metal coffee brewers. The model illustrated at the left, one of several types now being made, works on the extractor principle. For those who prefer the other traditional methods of brewing coffee, percolators, drip, and vacuum brewers are made
PLASTIC PICTURE CORD has been introduced as a nonmetallic product to take the place of orthodox steel picture wire. Of great tensile strength and readily cleaned, this new cord will serve as leaders for fishing lines and for general mending wherever steel wire is usually needed
A CARPET-CLEANING POWDER (left) is being made which dispenses with water and allows the carpet to remain where it is. The powder is simply sprinkled on the rug, brushed in, and removed in about one hour with a vacuum cleaner. After treatment a soiled rug turns several shades lighter
THIS NEW KNIFE SHARPENER, equipped with a high-grade bronze-bearing and selflubricating hone, is designed so that the guide slots automatically hold the knife blade at the correct angle for sharpening. Available in ivory, white, red, and green enamel finish, it is handy in the kitchen
A PAPER BALER for use in conserving waste paper and magazines may prove a great help to the busy housewife who has no handy corner or cellar space for storage. The model shown above comes with a spool for string or cord, and has a guarded holder for a single razor blade or other cutting instrument.
THE LIBRARY OF GAMES from which the above samples were taken contains 18 "volumes" in all, including many of the games of chance and skill that most adults enjoy. Designed on a pocket-size scale to look much like books, the games are ideal for travelers or men in the armed services.
DISCOLORATION on the inside of pots and pans can be removed by boiling a solution of cream of tartar (left) in the utensil for a few minutes. The brightness of the metal is restored by polishing with a very fine steel-wool scouring pad. If the inside of your teakettle is coated with lime deposits, heat the kettle gently without water, then tap the bottom lightly with a wooden mallet or spoon until the coating is loosened (below, left).
IT IS said that it costs $75 in hand labor to use up 75 cents worth of sandpaper. Sanding is certainly an irksome task, for it is hard, time-consuming work, and much of it must be done just when a piece of furniture is nearly ready for finishing.
THESE modernistic individual salt shakers give plenty of practice in sanding small pieces to size. Each shaker is built of three pieces, the middle one having a square hole scroll-sawed out of it. Sand the parts to thickness and square them, afterward rounding the corners by rolling them against a sanding disk or belt.
ALTERNATING-CURRENT motors having windings on both rotor and stator, and carbon brushes bearing against a commutator, are of the repulsion-start induction type. Such a motor is capable of starting machines under heavy loads, such as pumps and compressors.
DISTINCTIVE Gift Jewelry MADE FROM SCRAPS OF PLASTIC
IF YOU enjoy working with plastics but find new material costly or hard to get, why not use up those left-over bits in your scrap box by making jewelry of them? Very small pieces can be turned into attractive articles, and the work is fully as interesting as that of making larger projects.
PARENTS like to keep a permanent record of the growth of their children, and children, too, are much interested in looking at the marks which show their height at various ages. Often this record is made in pencil on some door jamb, only to be obliterated when the room is repainted or lost when the family moves away.
TWO-RAIL operation is the present achievement or the ultimate goal of a majority of model railroaders, and there is much to be said in its favor. It eliminates the third rail, thus (1) reducing the cost of materials, (2) saving a great deal of trouble at the switches, and (3) greatly improving the appearance of your pike.
CIVILIAN-DEFENSE wardens of Area 463 of Oakland, Calif., have built five firefighting carts as part of their emergency preparedness program. Each of these cost about $75 fully equipped. The work was done in the writer’s home workshop and in nearby garages.
BUILDING and operating marionettes is a fascinating hobby, but suitable stages for presenting them are a problem. Most stages are heavy, cumbersome, and expensive, and take too long to set up and knock down, especially at Army camps where conditions are often not ideal.
THEIR ESTERS USED FOR MAKING SOAP, SCENTS, AND EXPLOSIVES
KENNETH M. SWEZEY
KITCHEN-FAT salvage is turning American homes into an important source for war materials. Fats make soap and, more important, the glycerin needed in nitroglycerin dynamite, compasses, recoil and depth-charge mechanisms, gears, and hydraulic equipment.
ELECTRIFIED BUBBLE EXPANDS. To show that electrified particles repel each other, join together short pieces of metal and rubber tubing, and blow a soap bubble on the end of the metal tube, pinching the rubber to keep in the air. Electrify a hard-rubber comb by rubbing it briskly on wool, then touch the comb to the metal.
ANY amateur experimenter will enjoy using the homemade spectroscope shown here. A cheap equilateral prism, costing about $1.50, is all that need be bought. An 18-inch mailing tube, blackened inside, forms the body. Chip a small mirror to fit the tube, and draw a line with a sharp knife through the silvering.
COST and utility make it well worth your time to build your own loop antenna to modernize your old radio and get rid of unsightly tangled wire strung along the floor or hanging out the window. The cost is but a few cents, very little time is needed, and you can design the new antenna to fit your individual cabinet.
BATTERY-OPERATED UNIT BUILT FOR SIX TYPES OF PRONGS
ARTHUR C. MILLER
THIS tube tester is compact enough for the serviceman’s brief case or tool box and simple enough for the radio owner who does his own servicing. It will handle 80 percent of all tubes made, and, with slight alterations, can be adapted for others.
FM ANTENNA DESIGN takes a big step toward simplification with the circular type shown at left, which was developed by General Electric engineers for ultra-highfrequency transmission. The new antenna is said to have the advantage of radiating a substantially uniform energy in all directions without employing a complex and comparatively costly structure.
FOR home owners who can’t get fuel oil but have plenty of cheap wood available, a homemade gas generator developed by the Connecticut Agricultural Experiment Station at New Haven, Conn., and the Mason Laboratory of Yale University may solve the heating problem.