ANYONE who has done much house painting knows how difficult it is to make paint stick to galvanized iron surfaces such as down spouts and eaves troughs. With a new chemical primer now on the market, however, the problem is simplified. Sold as a liquid, it is either painted or sprayed on the cleaned galvanized surface.
Q.—Is THERE any quick way of removing old putty from window frames?—R. F. S., Worcester, Mass. A.—PUTTY is usually cut out cold, special "hacking" knives being sold for the purpose. Another method, however, which is said by many painters to be a time saver, consists of heating an iron rod, such as a poker, and applying it to the putty to soften it.
THE largest and in many respects the most remarkable clipper ship ever built in the United States was the Great Republic. For those who wish to build a model of her, we are offering a construction kit that contains all the necessary raw materials and full-size blueprints.
FOR the last two years, I have been a constant reader of your magazine and consider it to be excellent. I have followed the Model-of-the-Month page and now have to my credit models of the Normandie and U. S. S. Saratoga. I have written to you for two reasons.
PROJECT your mind a hundred years into the future; imagine yourself in the year 2036. A century has passed since the 200-inch telescope mirror for the California Institute of Technology came from the annealing oven, since the China Clipper spanned the Pacific on its first flight to the Orient.
Scientific Prospectors Use Strange New Instruments To Make Rocks Glow with Weird Light, Disclosing Presence Of Ore Veins that Contain Rare and Valuable Substances
MAGIC black light that makes rock appear to burn with living fire, now is being used to trace lost ore veins, to sort metalbearing materials, and to detect the presence of valuable minerals in what seem to be merely pieces of dirty, worthless rock.
WHILE an observer watches the process, the tiny cells of which living matter is constituted may now be whirled to destruction in a remarkable new research instrument called the centrifuge microscope. Material for study is placed in a small glass chamber, rotated at speeds up to 10,000 revolutions a minute, and illuminated by a momentary flash of light at each revolution.
TO GUARD workers against inhaling particles of lead, considered one of the most dangerous of industrial dusts, a mask of new design has been introduced. By inhaling through a filter bag, which has a sufficiently large area to avoid interference with easy respiration, the user is protected against lead dust formed in certain industrial processes.
CAPABLE of making ninety miles an hour on land and fifteen miles an hour in the water, a speedy amphibian automobile constructed by an inventor of Darmstadt, Germany, recently demonstrated its sea-worthiness in trials on Lake Muggel, near Berlin.
DESIGNED for mapping from a higher altitude than has ever before been practical with multi-lens equipment, a giant nine-lens camera just completed for the U. S. Coast and Geodetic Survey embodies several radical innovations in aerial photography.
HOME gardeners are now offered a portable, electrical soil-heating kit for stimulating and controlling plant growth, enabling them to enjoy the same advantage as commercial florists and market gardeners employing large-scale installations of this type.
How "plane," or flat, mirrors can be used to produce a stereoscopic illusion, giving ordinary pictures a three-dimensional effect, has been demonstrated by a Bridgeport, Conn., inventor. A flat mirror, split into two sections that are mounted at a slight angle to each other, is placed at a forty-five-degree angle to the user’s line of vision and the picture is viewed through it.
GERMAN engineers have just equipped a Berlin stadium with a novel public-address system, eliminating queer "echo" effects that often bother spectators listening to an announcer’s voice coming from main and secondary loudspeakers at once.
REPRODUCING the ups and downs of an actual seismograph record, a paper "cam" on a new testing mechanism devised at the Massachusetts Institute of Technology, Cambridge, Mass., can recreate in miniature any recorded earthquake of the past.
DETACHABLE code numbers furnished with a new-type automobile key simplify the problem of obtaining a duplicate when the original is lost. The numbers, stamped on a projection which can be detached from the key and filed by the owner, give a lock-smith the needed data.
A GIANT wind indicator of novel design erected at an English airport is sixty feet long and twenty-three feet wide. Made of galvanized steel, the huge rotating arrow points into the prevailing wind to show pilots, even when still at a high altitude, the direction of the ground wind and enables them to maneuver for landing.
A TANGLED mass of interlocking wire strands screens the workman examining an undersea communication cable in the odd photograph reproduced at the right. The cable, containing telephone, telegraph, and radio-broadcasting circuits, is being laid across Bass Strait, a body of water separating the island of Tasmania from the mainland of Australia.
WHEN a camper found a specimen of a rare type of glowworm in the woods near Sumneytown, Pa., he took the odd photograph above. The picture was snapped in the darkness, with no light except that given off by the luminous insect itself. The greenish glow radiating from the body of the worm proved sufficient illumination to register upon the photographic film, with an exposure of thirty seconds.
DESCRIBED as "quicker than lightning," a recording device perfected by General Electric Company engineers has the ability to remember and photograph past happenings. Called a pre-recording oscillograph, the machine translates the electrical impulses that travel along a power-transmission line into visible, wavy lines upon a screen.
AUTOMATIC bowling alleys recently introduced require no attendants. When a pin is struck, it is knocked loose from a magnetic plate embedded in the alley, permitting a spring to hoist it into a receptacle above. When the pins are to be set up again, an electric control lowers and raises the bank of receptacles, leaving the pins in place.
USING less energy than is required to light a pocket flash light, and employing aerials less than an inch long, a microray radio service across the English Channel aids private planes flying between England and France. By means of ingenious ten-foot aluminum reflectors, the tiny radio waves are concentrated like light into directional beams which carry the messages between the two stations, one at Lympne, England, the other at St.
TO TEST the practical value of cast iron as a highway surface, Prof. E. W. Davis of the University of Minnesota is conducting experiments with an odd automobile treadmill. Actual road conditions are simulated by using a stationary auto whose tires rotate on a whirling artificial pavement formed by two 1,000-pound wheels of corrugated cast iron.
A RECENT survey of the United States’ helium supply shows ample reserves for years to come. This country holds a virtual monopoly of the valuable gas, which replaces inflammable hydrogen for filling airships and balloons.
DOUBLE doughnuts, composed of rubber and hair cloth, form the latest innovation in automobile upholstery. Looking in cross section like rows of tiny figure eights standing on end, these cloth-and-rubber springs form two honeycomb layers between the regular steel springs and the top fabric of the seat.
BY RECORDING automatically the length and width of a hand, a new instrument insures perfectly fitting gloves. The device is the invention of Prof. A. C. Davis, of Cornell University, Ithaca, N. Y. When a purchaser inserts his hand through an adjustable metal loop at the bottom of the instrument, the middle finger comes in contact with a movable button which is pushed forward a distance corresponding to the length of the customer’s fingers, while the loop is tightened to measure the width of the hand.
WAR GASES may lose some of their terror if the claims of a French chemist, who announces the discovery of a chemical preparation that has the property of neutralizing their toxic effect, prove to be justified. An advantage of this anti-gas agent is the simplicity of its use.
JUSTIFY mountain terrible unseen. CPRXD VLMTP. These are not delirious ravings, followed by a jumble of spilled type. The first four words, in an old-style cable code, mean: "Motor breakdown. Send your nearest technician at once." And "CPRXD VLMTP" is a shorter, up-to-the-minute way of saying the same thing! It is from one of the newest codes, of artificial five-letter “words,” built according to the very latest international rules which in the last two years have been changing the cable language of the world.
WHETHER or not the same gun fired two bullets is shown by a "comparison camera" developed by a University of Wisconsin scientist. When its two lenses are focused simultaneously upon a bullet picked up at the scene of a crime, and a test bullet fired from a suspect’s gun, a composite photograph is obtained, consisting, for example, of the top half of one bullet and the bottom half of the other.
WHEN a movie actress appears to be gazing soulfully into the eyes of a dancing partner while gliding around the floor of a ballroom, she may actually be going through the motions of a fox-trot or waltz with a camera on wheels. A "dancing camera," devised in Germany for obtaining such close-up shots, is attached to the performer by a leather belt strapped about her waist, while her arms rest on supports and maintain a realistic pose.
A NEW attachment operated by a foot pedal sets a typewriter carriage back for another line without the hands being lifted from the keyboard. When a typist comes to the end of a line, she presses her foot on the floor pedal; this is connected to an automatic spring mechanism on the rear, righthand side of the machine which pulls the carriage back to starting position and spaces the paper for the next line.
BINOCULAR and compass are combined in a single instrument developed in England. When the user sights through the field glasses, he sees the image of a built-in compass dial, projected into the field of view as shown in the drawing above. Thus he can readily view objects whose bearings he has ascertained from a chart, or obtain the bearings of a distant target to identify it on the map.
RIVERS of icy wind fifty miles wide and hundreds of feet deep, howling across the frozen wastes of the antarctic at seventy feet a second, will be harnessed by future generations to provide light and power, according to a forecast made by Prof.
POISONOUS wastes from factories along the River Tees in England are mixed to neutralize each other before they are dumped into the stream. When intermixed, British engineers discovered that two poisonous wastes, each from a selected factory, would combine chemically to form a harmless compound.
A PIPE wrench recently introduced cannot slip its hold; the harder the user pushes the handle to twist a section of pipe, the tighter the jaws of the tool grip the metal. Inclosed in the body of the wrench and attached to the upper end of the handle is a gear wheel engaging a rack in such a way that a turn of the handle opens or closes the jaws.
IN THE future, ships may have hulls made of aluminum instead of steel or wood. A six-ton, aluminumalloy hull "fragment," representing a ten-foot cross section of a 100-foot boat, was launched recently at Bath, Me. It will undergo extensive tests at Newport News, Va.
PATTERNED after a diminutive type of airplane that has attained wide popularity in Europe, a novel single-seater biplane constructed by a Cincinnati, Ohio, pilot is under six feet high, has a wing spread of less than twenty feet, and weighs but 316 pounds.
GLASS ornaments and drink stirrers light up mysteriously when brought near a table recently marketed for use in bars, cafes, and restaurants. Electric current operates a radio tube and transformer in the pedestal of the table. A high-voltage, low-amperage charge is transferred to a tinfoil filament under the composition table top, setting up a high-frequency field.
CARDBOARD signs of a new type glow in the dark by reflected light. Small holes punched in the letters of the sign let light through to a thin sheet of metal foil which has been stamped and indented to provide a number of reflecting surfaces.
FURNACES glow, fire-box doors swing open, a mixer grinds, glass stirrers whirl, and tiny electric trucks trundle pots of "molten glass" to a casting table in an ingeniously constructed miniature glass factory recently completed by the Bausch & Lomb Optical Company at a cost of $8,000.
TO REMOVE ashes from a pipe recently invented, the smoker merely pulls apart the cherry-wood bowl, which is constructed in two sections hinged at the bottom. When the hinged halves are closed, two flanges of heat-resisting metal set into the wood overlap to form an air-tight joint.
PERSONS afflicted with narcolepsy, or constant sleepiness, are being treated with benzedrine, a new drug which keeps people awake. In a recent test, nine chronic "sleepers" who received the drug obtained complete relief. Benzedrine is also useful in treating muscular disorders.
READILY portable and operated from any electric outlet, a new compact stroboscope may replace bulkier and costlier models heretofore employed in industry to make moving machinery appear to stand still in order to check the behavior of rotating and vibrating parts.
GIANT loudspeakers take the place of bomb racks under the fuselage of a huge war plane used by the British Royal Air Force to subdue rebellious native tribes in Irak a British mandate in Mesopotamia. Officers report that words of warning spoken into cabin microphones and thrown down from the sky by means of powerful amplifiers prove more effective than bombs in quelling tribal revolts.
ABRASIVE wheels are easily leveled and made true with a spiral cutter recently marketed. The device is held against the wheel as it revolves; it is not necessary to move it back and forth across the wheel surface, since the spiral arrangement automatically trues the wheel.
HIGHWAY patrolmen employed by the Automobile Club of Southern California (P.S.M., June ’35, p. 20) now tour the roads in new three-wheeled motorcycle trucks fully stocked and equipped to render mechanical and medical first aid to motorists in distress.
WOOD CHOPPERS in Alabama, not long ago, stumbled upon six mysterious tree stumps. In the hollow of one, they noticed a wad of sodden paper. It proved to be $300 in rotting bills. A quarter of a mile away, another stump held $200. Axes were thrown aside and a treasure hunt ensued.
A CROSS the continent roars a trimotored airliner, recently retired from commercial service. In her large cabin, a dozen young men are busy mapping her course, taking shots at the sun with an octant, figuring drift, correcting air speed for altitude and temperature.
SEEING in the dark is literally made possible by an amazing “electron telescope” just perfected by Dr. V. K. Zworykin of the Radio Corporation of America. Startling applications result from its ability to transform invisible rays of infra-red or “black” light, emitted by unseen objects, into visible images of the objects.
"HOLED THROUGH” months ahead of schedule and seventy-five percent completed at this writing, the new Midtown Hudson Tunnel linking New York City and New Jersey reflects the striking progress that has been made in engineering methods in the last few years.
IN HOLLYWOOD you will find more sane people performing crazy jobs than anywhere else in the world. Painting horses’ tails, for instance. Or bleaching steer bones, breaking crockery, painting blood stains on shirts, waxing and polishing artificial fruit, painting natural flowers odd colors for the camera, spinning giant spider webs, grunting and groaning and shrieking in imitation of birds and animals, chasing bedbugs, and submitting to snake bites.
SITTING back to back aboard a two-way scooter of their own design, two San Francisco, Calif., boys enjoy a novel form of coasting on the city’s hilly streets. One boy steers the odd vehicle as it rumbles to the bottom of a hill and coasts part of the way up another. Then, without turning the six-wheeled car around, the second boy takes the other steering wheel to guide the scooter back down the slope.
CORN harvesting is made easier by a two-purpose knife just introduced. The tool has two "hooks" notched out of the dull edge of the blade, one at the end and one in the middle; with these the farmer pulls up leaning or fallen corn stalks to the right position for cutting with the sharp side of the blade. The hook at the end of the blade is used for handling stalks that have fallen flat, while the one in the middle picks up those that are leaning over.
MEMBERS of a newly founded French "underwater" club use a novel type of diving outfit. Transparent, water-tight masks cover the face and are held in place by straps fastened about the head. When submerged, the divers breathe through long rubber tubes, the ends of which are held above the surface by metal clamps attached to floating rings resembling life preservers.
ECHOES of artificial thunder discharged from the loudspeaker of a new sound apparatus are accurately measured by means of a whirling neon light to test the acoustics of a room. Both the clap of "thunder" and its various reverberations from walls and ceiling are picked up by a sensitive microphone, amplified, and made to flash a neon bulb which spins on a rotating arm.
A CIRCULAR oilstone with an ingenious guide makes it easy to hold chisels, plane blades, and other bevel-edged tools at the correct angle during sharpening. Grasped in a special holder, the tool is moved back and forth over the stone, while a ball-bearing post beneath the holder rides along the surface of a disk-shaped guiding table.
WALLS act as radiators in a concrete house erected recently in Red Bluff, Calif., as an example of a new method of building construction. Warm air from a special type of heating plant rises through half-round asbestos flues embedded in the walls, and the heat is radiated from the inner wall surfaces into the rooms.
STARTING near the roof of a huge indoor arena, ski jumpers whizzed into space from what was called the first indoor ski jump in the world, erected recently for a winter-sports carnival at Boston, Mass. Tons of "snow" covered the slide, which was 200 feet long and seventy-five feet high.
LEVELS of the atmosphere beyond the reach of balloons are now to be studied by pointing giant searchlights skyward. The rays, reflected to earth by dust and other particles, will be collected for study with mirrors like the one shown above.
BURGLARIES occur most frequently in cool weather: murders in hot weather. NINETY PERCENT of the storms in the United States pass out to sea within a radius of 300 miles of Plymouth Rock. BRAZIL NUTS are not eaten in Brazil. RED HAIR is more common in Scotland than in any other country in the world.
SMALL skin blemishes are detected by a giant enlarging mirror in use in a London beauty shop. Light from a powerful electric lamp is diffused through a circular glass screen onto the face of a customer. A concave mirror in the center of the illuminated screen reflects and magnifies images of portions of the face so that minute skin defects hard to find with the naked eye are easily discovered.
WITH the aid of one of the world’s largest electromagnets, the coldest temperature on record has just been produced at the University of Leyden, Holland. The new mark is within three one-hundredths of a degree F. of absolute zero, the point at which a body contains no heat.
COLORED printing inks can be mixed accurately to produce any shade desired, by the use of an ingeniously designed ink-matching kit now available. The user squeezes ribbons of ink onto a plate-glass mixing slab from tubes containing basic colors, following directions on a color chart and measuring the correct amount of each color by means of a graduated measuring sheet placed under the transparent slab.
SPRAWLING beneath the ruins of an ancient hilltop castle, a huge greenhouse under construction near the shore of the Black Sea, in Southern Russia, half circles the hill and extends up the steep slope in a series of giant steps. Located in a citrousfruit district, the mammoth hot-house accommodates an entire grove of lemon trees.
BASED on the principle of absorbing sound rather than blocking it, a noise-proof telephone booth recently introduced has no door and is completely open around the bottom. Perforated metal sheets lining the walls and ceiling are backed with sound-deadening balsam wool to suppress outside noises.
WHEN an accident wrecked the radiator of his car, a motorist in the sparsely settled Black Hills region of South Dakota improvised a new one in order to run his auto to the nearest repair shop, 230 miles away. He adopted the ingenious method of clamping an empty oil drum on the front bumper, filling it with water, and connecting it to the engine’s circulation system.
WATCHFUL as a mother bird over its nest, a German nature photographer stood guard for weeks to catch a pheasant emerging from its egg. His patience was rewarded by the remarkable set of photographs reproduced here, which are believed to be the first of their kind to show the birth of this game bird.
BY SUPPLYING music for dances and entertainments with sound equipment of his own construction, Samuel Coombs, Columbia University senior, has been paying his way through college and obtaining funds to experiment with novelties in sound effects.
A NEW glass brick of improved design is now available to architects and engineers who have been experimenting with glass as a building material. By a special process of enameling and sanding, the edges are given a roughened surface to which mortar adheres readily.
SHAPED like a giant acorn, a new type of street lamp reduces road glare and also prevents light from shining in the second-story windows of near-by houses. The light source is concealed within the opaque upper half of the lamp fixture so that all the rays are thrown downward onto the road.
FOODS may now be stored in rented refrigeration lockers, much as valuables are kept in bank safe-deposit boxes. Householders and farmers in the North-west buy wholesale quantities of meat, fruit, and vegetables when the supply is plentiful, and the food is frozen and placed in lockers which are kept near zero in cold-storage plants.
Preserves Cloth, Forms No Scum, and Lathers Easily
"SOAPLESS soap" is a new product of synthetic chemistry. Actually a brand-new chemical compound, it looks like soap, makes soaplike suds, and is used exactly as soap is. In fact, according to laboratory workers who have spent five years bringing it to the point of commercial production, it does everything that soap does, and does it better.
ANGLERS may bend a new flexible lure into numerous, different shapes to imitate a large variety of fishlike movements in the water. Made of a tough pliable material, the bait, when twisted to any desired form and pulled through the water, has a swimming action said to be exceptionally realistic.
BECAUSE it has a long, solid heating element instead of the usual flat resistance coil, an improved electric lighter of the "pass-around" type can be used to light pipes as well as cigars and cigarettes. The base of the unit is connected to a wall plug and the handle of the "match" pressed down until the element glows.
GIANT CARDS SHOW PLAY AT CHAMPIONSHIP BRIDGE MATCH
GIANT playing cards, seven feet tall and moved by attendants, kept a vast audience informed of each play at a recent international bridge match held in New York City. The experts played in a soundproof, glass inclosure while the fifty-two giant cards were arranged on a stage in groups of thirteen to represent the playing hands.
BRING on your G-men of natural history and let them try to solve the many mysteries in the realm of old Mother Nature! On second thought, maybe a Philadelphia lawyer is needed to untangle some of the natural laws that seem to have gone askew and are out of kilter.
JIMMY, the shoebill stork, was going under the anesthetic. A stone, thrown by a boy visitor to the Bronx Zoo in New York City, had smashed into the huge bill of this rare bird, cracking it open. Tiny spores of mold, similar to that seen on stale bread, were attacking the delicate exposed tissues.
Fascinating Experiments Made with a Gyroscope Top Illustrate an Amazing Astronomical Theory
MOST people know that all our earth’s seasonal changes are caused by the slant of the globe’s axis in relation to the plane of its orbit around the sun. But few people have probably given very much thought to the forces which have caused this slant.
The heavy metal ball set in the handle of this new stainless-steel ice pick is intended for pulverizing ice. It is put in the handle in such a way that the pick cannot roll away When the tub is to be used, the wash basin is swung back into the corner where it is entirely out of the bather’s way SWINGING WASH BASIN.
Sulphur Dioxide Provides Fascinating Home Experiments
Sulphur Dioxide Provides Fascinating Home Experiments
STRANGE PROPERTIES OF THIS GAS EXPLAIN PRINCIPLES OF MECHANICAL REFRIGERATION
Raymond B. Wailes
IF YOU have ever burned any sulphur in your home laboratory, the pungent smell of the vapor probably lingers in your memory. This is what most people mean when they speak of the odor of sulphur. The fact is, however, that sulphur has almost no odor of its own.
A HANDY dispenser for small quantities of water obviates the inconvenience of making up a few drops of a solution, or filling a graduate exactly to a given level, with water from a running tap. The device illustrated may be assembled from a flask or bottle, a two-hole rubber stopper, a few pieces of glass and rubber tubing, and the rubber bulb of a ten-cent atomizer.
VACUUM CAUSES AN UNEXPECTED EFFECT You would think that the stream of air blown between the table-tennis balls would force them apart. Instead, it creates a partial vacuum that draws them together A BUZZER MAKES A SIMPLE SHOCKING MACHINE Connect a tin-foil grip to one of the binding posts of a buzzer operated on a step-down transformer, and another to the contact arm.
RESEMBLING a magic wand, the newest tool for amateur experimenters and set builders makes it an easy matter to check the tuning inductances in any receiver. Placed in the magnetic field of the inductance, it determines instantly whether the inductance is too high, too low, or just right.
THIS simplified, inexpensive amplifier will make any headphone receiver a loudspeaker set. If you are a short-wave experimenter, it will make it possible for your friends to hear your oneor two-tube outfit with real loudspeaker volume.
"SO THAT’S the bunk they teach my boy at school!" Bill Simpson sputtered, shoving an elementary science textbook under Gus Wilson’s nose as the garageman pulled into the Simpson driveway in response to a trouble call phoned to the Model Garage.
DID you ever try to cut a delicate pattern from thin sheet metal without bending it? If not, perhaps you want to engrave figures or lettering on metal, such, for instance, as the numerals on a clock dial. Acid can be made to do both of these jobs without any disfiguration of the metal such as you would get if you tried to do the cutting or engraving by mechanical means.
HERE is a table lamp that will appeal to any one interested in ships and the sea. To ship model makers, it offers an opportunity to construct something quite different from the usual line of models. The standard represents the mainmast of a schooner, with the various fittings and a portion of the deck worked out to a suitable scale.
THIS homemade power hack saw has given satisfactory service for several years and has even sawed off several pieces of railroad iron, which shows that it is built for real work. The stand is rigidly constructed from 1¼-in. angle iron and is braced with ¾-in. angle iron.
FOR bending and shaping large wire or the smaller sizes of metal rods or bars, an improvised bending jig like that shown is useful. It consists of a portion of an old gear rack and two or more bolts or steel pins. The rack is placed along one jaw of the vise, and the pins are clamped between the teeth at the desired distance apart.
WHEN you wish to cut ovals or circles in paper, as in making black paper masks for photo printing, try using a glass cutter instead of a knife or razor blade. It will follow any curve with ease and make an absolutely clean cut. Place the paper on a sheet of glass, as shown in the illustration.
The mounting is made in the simplest manner from a single sheet of highly polished, brilliant cast-resin material
ALBERT Q. MAISEL
WHILE clock movements them-selves do not cost much, good modern designs in clock cases usually are quite expensive. The amateur craftsman, however, can produce a desk clock of cast-resin plastics like the one illustrated within a few hours, and in quality and appearance it will fully equal the commercially available types.
ARIONETTE stages are of many types, simple and complex. If it were possible, I should have every one start with an outdoor theater. There is nothing more delightful, and it is quite easy of achievement. We shall begin, however, with a small portable stage that may be used in the average doorway (marked Fig. 1 in the drawings).
THE "Lion of Judah," familiar symbol of Ethiopia, is now represented in a new block puzzle that originated in the Orient. It forms an entertaining project for whittlers. A close-grained hardwood such as maple gives the best appearance, but white pine, of course, is much easier to work.
A MINIATURE hand magnifier can be made in an emergency as shown at the right. Form a small loop in one end of a piece of copper wire and fasten the other end in a cork. Dip the loop in water glass (sodium silicate) and place in a level position to set.
ANY amateur microscopist who has struggled with the problem of manipulating a small insect so that it could be studied from all angles will find useful a gadget similar to the one illustrated below. It can be made of any material at hand. A small block of softwood (pine or balsa) or cork glued to a piece of stiff cardboard or cigar-box wood, with a darning needle or a long glass-headed pin stuck through, will serve very well.
A SMALL adjustable air vent may be made, when necessary, from two vacuum or compression can lids. They are laid off in eight sectors, and every other one is cut out with a chisel. One lid is fastened to the screened opening; the other is attached with a bolt, two nuts, and a small spring so that it can be turned as required, yet will remain in whatever position it is set.
AMONG the two dozen or more airplane designs given in this series have been included army and navy ships, commercial and passenger transports of both land and water types, racers and sport planes, and others designed for general use, but this month we are offering something different— plans for making a simplified model of a modern mail plane.
How to duplicate the simple but beautiful piece that won first place for handmade furniture in the National Homeworkshop Guild's great contest
H. C. KEYSOR
THE home workshop fan usually spends much of his shop time in making various gadgets which his wife considers quite useless. He has urgent need of a new tool cabinet, and that old tea cart will serve very well as a telephone stand.
WITH a few black walnuts and some pipe cleaners, you can make a variety of comical novelties for use as favors and gifts. The laughable expressions on the "faces" of these strange birds and animals make them interesting to adults as well as children.
A SMALL spotlight for photographic purposes can easily be made in such a way that it may be attached, when required, to any photoflood reflector. A disk of tin should be cut to fit the reflector. The one illustrated is 10 in. in diameter. Three ears are soldered to the edge and bent to snap over the rim of the reflector.
THE object of the easily made puzzle illustrated above is to get the split metal ring off the wood disk. After trying for a time, most people find that they have worked the ring right back to the center where it started from, unless they are either unusually lucky or very systematic.
Magical little device will operate a photographic exposure meter or automatic garage-door opener . . . It will guard rooms, turn on lights, and do many stunts
WORKMEN passing between the sun and a bank of copper oxide rectifier disks were responsible, a few years ago, for the discovery of a new type photocell or the so-called "electric eye." It was found that light falling on a disk of copper covered with cuprous oxide was converted directly into an electric current.
HINTS ON ASSEMBLING SOAP-BOX RACERS and Midget Autos
THOUSANDS of boys are getting ready to build new midget cars in the hope of entering the soap-box racing events that will be held in many cities and towns this summer. Others, who are too old for this type of contest and have progressed beyond plain coasters, are interested in constructing miniature automobiles that have their own power plants, usually a one-cylinder motor.
Installing the RIGGING on Our New Model of the GREAT REPUBLC
PART IV OF A SERIES OF ARTICLES ON A FAMOUS AMERICAN CLIPPER SHIP
E. Armitage McCann
ONCE the spars are made as described in last month’s issue, we are all ready to begin rigging our model of America’s largest clipper ship, the Great Republic. She was heavily rigged. Her lower shrouds, for example, were of rope 12½ in. in circumference; her topmast shrouds, 8 in., and other gear in proportion.
HERE’S A HOMEMADE camera Tripod that never slips, sways, or skids
HERE’S A HOMEMADE camera Tripod that never slips, sways, or skids
ONE of the old comedy stand-bys is the photographer whose tripod collapses just as he is taking a picture. It is funny to the audience, but no laughing matter to the serious picture taker. Any one who has attempted to set up a tripod on a tin roof or a polished ballroom floor knows just how exasperating a task it is.
Ingenious Methods Found By Our Readers to Solve Common Motoring Problems
THREE people can sit comfortably on the two front seats of the average two-door coach if the car owner builds the easily made filler seat illustrated above at the left. It consists simply of a rectangular wood frame or base padded and upholstered to bring its top flush with the two seats.
How to Develop GOOD PROGRAMS For Home Workshop Clubs
MUCH of the success of any home workshop club depends upon the type of programs presented at its regular meetings. Out-and-out home workshop enthusiasts are, of course, glad to have a chance to meet merely to talk over their problems and be in that atmosphere of cheery companionship which surrounds any group of men who are mutually interested in craftsmanship.
IN TURNING many small pieces of wood to ¼ in. in diameter or less, a collet like the one shown above will save much time. Take a piece of hardwood, a trifle larger than the center in the headstock of the lathe, and turn it to the same taper as the center, and cut off both ends square.
NO MATTER how much or little time you have for your home workshop activities, it pays to concentrate your efforts on worth-while projects. To help you do this, we offer a series of blueprints of well-tested projects designed by experts. The following is a selected list, but many other plans are available.
AN ATTRACTIVE type of wooden costume jewelry is represented by this walnut bracelet, which was made by Russell Hand, of Pasadena, Calif. The ivory-colored birch dowels heighten the effect with a polkadot design. First cut a disk of 1-in. walnut, about 3¼ in. in diameter to allow for a 3-in. finished diameter.
IT IS not easy to hold a small, round piece of wood under a drill press or other tool, but a clamp may quickly be made for this purpose as shown. It should be cut from hardwood about ⅝ in. thick and holes bored 1/16 in. larger in diameter than the work to be clamped.
THE adjustable radius turning tool illustrated below turns radii from ⅜ to 1¾ in. The tool bit in the revolving head is moved by means of the handle at the other end. The bit is set to the required radius by measuring with micrometers from the tip to the back of the holder.
THE two pairs of homemade ski covers illustrated in the photograph at the right are designed to protect a skier’s feet from wet snow and prevent the snow from balling up under his boots, which is one of the common annoyances that reduce the pleasure of the sport.
IF A CORRECTLY ground wire drill cuts large, the frist thing to do is to check up the concentricity of the chuck. If you find no trouble there, you had better shorten the drill ¼ to ½ in. and repoint it. Geared scroll chucks must operate freely, and they should be kept so with a good cleaning out every four or six weeks.
THE neatest way to carry a group of tools or instruments required for one particular kind of job is in a fitted case. Radio repairmen, amateur microscopists, photographers, and followers of many other hobbies find a fitted case convenient because it keeps the instruments or tools in good condition and reveals at a glance if anything is missing.
DURABLE and inexpensive valves for water pumps of the type used in rural communities may be made from a piece of rubber cut from a heavy inner tube. They take only a few minutes to make, yet my experience has been that they outlast ordinary leather valves and also give a better seal so that the pump needs no priming.
CLAMPING a thin piece of wood for gluing so that it will not warp is always difficult. If the thin piece is a split canoe paddle or the blade of an oar, and you are without the usual tools, it seems next to impossible. Any basement, boathouse, or camp will have the essentials for making a good job—light cord, a few nails, a knife and hatchet, and some sort of waterproof glue.
A CASE to keep small files from rubbing together can easily be made on a lathe. Take a piece of wood about 1¾ in. square and 6 or 7 in. long, and with brace and bit bore a 1¼in. hole in one end to a depth of 5½ in. From another piece of the same size wood, turn the bottom as shown.
EXCELLENT handles for small files and carving tools may be made from discarded siphon-bottle gas bulbs such as are used to prepare charged water at home. My method is to drill out the soft metal plug, fill the bulb half or three quarters full of sand, and then pour melted sealing wax level with the top.
MOUNTED on a sturdy base that swings under the workbench when not in use, this grinder is always handy, yet takes up no bench space. By locating this accessory in line with a motor used for some other piece of equipment, the need for a countershaft or extra motor is eliminated.
THE average operator of an engine lathe, whether in a home workshop or a factory, has probably more than once become vexed at "running out of thread" when using the compound rest. Instead of doing something about it, he is likely to reprove himself for not making a better guess as to whether or not the thread was ample for the length of the cut.
BUTTONS that are especially suitable for sports clothes may be made from nuts such as the American (black) walnut and the hickory nut. All that is necessary is to clamp the nut firmly and cut it crosswise into slices of the desired thickness with a fine-toothed saw.
DESIGNED to hold a complete set of wood-turning tools, the rack illustrated can be attached to the wall or set on the bench, just behind the lathe. Most craftsmen prefer to have their lathes placed in front of a window, in which case there is no convenient place to keep the turning tools.
THE file, handsaw, hack saw, and wood plane are four tools that are often used or misused in such a way that they quickly become dull and give inefficient service. Some men, when using a file, will apply practically the same pressure on the backstroke as on the forward stroke.
ADHESIVE TAPE WILL PROTECT YOUR THUMB WHILE WHITTLING
IF WHITTLING makes your thumb sore, apply a piece of dry-back or surgeon’s adhesive tape to it before starting work. Another piece can be placed where the back of the knife bears on the forefinger.—P. O’N. THE BEST SIZES TO MAKE BIRD-NESTING BOXES
V-BELTS for home workshop use may be made, when necessary, from remnants of good leather belting bought at a junk yard. For 25 cents I purchased a long, narrow strip that was sufficient for a dozen belts. I beveled the edges of two laths as shown, nailed one to the workbench (setting the nails), placed the strip of leather alongside the beveled edge, then placed the other lath snugly against the leather, and nailed this lath to the bench.
WHEN heated to a blue color, a wood screw can often be driven into a board that otherwise would certainly split. An extreme example is illustrated. The screw was driven while hot through the wood without first drilling a hole or making any kind of entering point.
WHEN working with an independent four-jaw lathe chuck, it is often necessary to reverse the jaws. The chuck key is satisfactory for tightening and adjusting the jaws, but is very slow and tiresome for reversing them. For quick work, square the end of a 3-in. piece of drill rod, insert it in a hand drill, and use as illustrated above.
IN BORING jigs on a milling machine, the use of the graduating lines on the machine is not very practical. One hole will generally be bored at the proper location, and succeeding holes determined from the first. As the holes are bored to plug-gage size, it is necessary to keep reboring these holes and making adjustments on the table until the proper distances are obtained.
WHEN U. S. Army aviators recently bombed Mauna Loa, Hawaiian volcano, they executed the first recorded attempt to combat such an eruption from the air, and demonstrated a new peacetime use for bombing planes. Twenty 600-pound missiles loaded with high explosives were dropped from altitudes of 3,000 to 5,000 feet in an effort to halt a lava stream advancing upon the town of Hilo and the river that furnishes its water supply.
DURING the ten years of her life, an English girl who died recently never laughed, cried, expressed fear, joy, anger, or any other emotion, according to a statement by a prominent British nerve specialist. The child’s intelligence was rated as normal but there was a complete absence of emotion.
T-SQUARES and triangles often become nicked on the corners. They can be repaired by filling them with ordinary celluloid cement. Trim the lumps of dried cement with a narrow chisel, and finish with two or three light strokes of a fine file guided by the edge.
OLD tooth-paste tubes make very handy soldering paste containers. Cut off the crimped end and clean out the tube thoroughly. After filling it with paste, close the open end by folding over and crimping in a vise.
SIMPLY MADE Hygrometer Gives Direct Moisture Reading
WILLIAM E. BROWN
A SENSITIVE yet simple hygrometer of the wet-and-dry-bulb type can be made of glass tubing bent into a U-shape and filled with a volatile liquid such as carbon tetrachloride. In operation, the difference in temperature of the wet bulb and the dry bulb causes a difference in vapor pressure as indicated by the unequal height of liquid in the two arms of the U-tube.
EVERY one knows of the many uses to which old safety-razor blades may be put, but discarded holders also are valuable. The pin vise shown above was made from the handle of a wafer-blade type of razor and a 10-32 flathead machine screw. The top of the screw was built up with solder, a No. 75 hole drilled through the center of the screw, and the screw then divided into four segments by two hack-saw slits extending to within 1/16 in. of the end.
Three prize winning letters in POPULAR SCIENCE MONTHLY’S new Secrets of Success contest—"What Home Study Has Meant to Me"—are printed below. Read these stories carefully because your own career may be just as interesting and inspiring to other readers.
A new hobby that can be made to pay cash dividends
C. L. NEWCOMB
M. W. GIRARD
MAKING decorative plaster casts is a hobby that is not only interesting, but can easily be made profitable. There is a market for the finished product, and a good chance for profit because the actual cost of each article is low. Among the projects that can be made are coats of arms, medallions, book ends, and wall plaques of many designs.
IN THE usual method of laying out the studding for frame buildings, the bottom plate is spiked down and the top plate is laid on top, so that the edges of both can be marked at the same time. The position of one stud being located, the others are marked successively by resting the tongue of the square on the floor while the pencil is guided along the edges of the blade.
MICROSCOPE and telescope eyepieces and the common tripod magnifiers have long been used for microscopic work where a large field of view with medium magnification is desired. By the simple expedient of mounting the eyepiece in a ten-cent spectacle frame, both the operator’s hands are freed for use in manipulating or dissecting the specimen.
IF YOU wish to print titles, notations, identifying numbers, or other data on your photographs, yet do not wish to alter the film by writing on it directly, place the lettering on a sheet of cellulose wrapping material slightly larger than the negative, as illustrated above.
WHEN you wish to enlarge or reduce a drawing and a regular wooden pantograph is not at hand, try the simple method illustrated. All you need is a rubber band, a pushpin, and a small piece of celluloid. Cut the band into two parts, one longer than the other, and tie each to holes in the celluloid.
For testing the tenons used in joining furniture and other cabinetwork, whether they are cut by hand or with a tenoning machine, it is a convenience in any woodworking shop to have a gauge like that illustrated below. This testing block is merely a piece of hardwood of about the dimensions indicated with a number of mortises of assorted sizes.