The Boy Mechanic Part 65

** Mounting Photo Prints on Gla.s.s [231]

Photograph prints can be mounted on gla.s.s with an adhesive made by soaking 1 oz. of sheet gelatine in cold water to saturation, then dissolving in 3-1/2 oz. of boiling water. Let the solution cool to about 110 deg. F., then immerse the print in it and squeegee, face down, on a clear piece of gla.s.s. When dry, take a damp cloth or soft sponge and wipe off any surplus gelatine on the gla.s.s.

** Dropping Coins in a Gla.s.s Full of Water [231]

Take a gla.s.s and fill it to the brim with water, taking care that the surface of the water is raised a little above the edge of the gla.s.s, but not running over. Place a number of nickels or dimes on the table near the gla.s.s and ask your spectators how many coins can be put into the water without making it overflow. No doubt the reply will be that the water will run over before two coins are dropped in. But it is possible to put in ten or twelve of them.

With a great deal of care the coins may be made to fall without disturbing the water, the surface of which will become more and more convex before the water overflows.

[Ill.u.s.tration: Dropping Coins]

** Hollow-Grinding Ice Skates [231]

The accompanying sketch ill.u.s.trates a practical method of clamping ice skates to hold them for grinding the small arc of a circle so much desired.

The U-shaped clamps are made of 3/4-in. soft steel with the opening 6 in. deep and 5 in. high and are bolted to a block of wood, 2 in. thick, 6 in. wide and 12 in. long. The skate runner is adjusted to the proper height by 1/2-in.. set and thumbscrews. The block

[Ill.u.s.tration: Skate Runner Fastened in Clamp]

of wood holding the clamp and skate can be pushed along on the emery-wheel table in front of the revolving wheel.

If properly adjusted, a slight concave or hollow can be made full length of the runner, true and uniform which will hold on the ice sideways and not r.e.t.a.r.d the forward movement.

--Contributed by Geo. A. Howe, Tarrytown, New York.

** How to Make a Bicycle Coasting Sled [231]

The accompanying drawing and sketch ill.u.s.trate a new type of coasting sled built on the bicycle principle. This coaster is simple and easy to make, says Scientific American. It is constructed of a good quality of pine. The pieces marked S are single, and should be about 1 by 1-1/2 in.; the pieces

[Ill.u.s.tration: Has the Lines of a Bicycle]

marked D are double or in duplicate, and should be 1/2 by 1-1/2 in.

[Ill.u.s.tration: Coasting]

The runners are shod with iron and are pivoted to the uprights as shown, double pieces being secured to the uprights to make a fork.

The seat is a board, to the underside of which is a block, which drops down between the two top slats and is secured with a pin. A footrest is provided consisting of a short crosspiece secured to the front of the frame and resting on the two lower slats. The frame and front fork are hinged together with four short eyebolts, E, with a short bolt through each pair as shown.

** Spelling Names with Photo Letters [232]

There are, no doubt, many amateur photographers who make only occasional trips afield or through the more traveled thoroughfares with their cameras during the winter months. Each one is generally interested in working up the negatives that he or she made during the summer or on that last vacation into souvenir post cards, alb.u.ms and the like, for sending to friends. Ill.u.s.trated herewith is something different from the alb.u.m or photographic calendar.

The letters forming part of the word POPULAR are good examples of this work.

The masks which outline the letters are cut from the black paper in which plates come packed. Their size depends on the plate used.

A sharp knife, a smooth board and a straightedge are all the tools needed, says Camera Craft. If the letters are all cut the same height, they will look remarkably uniform, even if one is not skilled in the work of forming them all in accordance with the rules. Be sure to have the prints a little larger than the letters to insure a sufficient margin in tr.i.m.m.i.n.g, so as to have a white margin around the finished letters. The best method is to use a good pair of scissors or a sharp knife.

Many combinations can be made of these letter pictures to spell out the recipient's name or the season's greeting. During the holidays the letters may be made from winter scenes to spell "A Merry Christmas" or "A Happy New Year." An Easter greeting may have more spring-like subjects and a birthday remembrance a fitting month. The prints are no more difficult to make than the ordinary kind. In cutting out an 0, for example, do not forget to cut out a piece to correspond to the center. This piece can be

[Ill.u.s.tration: Letters Made from photographs]

placed on the printing paper after the outline mask has been laid down, using care to get it in the right position, and closing the frame carefully so that the small piece will not be disturbed. The letters should be of the kind to give as large an area of surface to have as much of the picture show as possible. What the printer calls black face letters are the most suitable.

By cutting the letters out of black paper in a solid form, and using these as a mask for a second printing after printing the full size of the negatives, these letter pictures can be made with a black border. So made, they can be trimmed to a uniform black line all around; and, mounted on a white card and photographed down to post card size, the greeting so spelled out makes a most unique souvenir. Another application of the letters in copying is to paste them on a white card as before, trim the card even with the bottoms of the letters, stand the strip of card on a mirror laid flat on a table, and then photograph both the letters and their reflections so as to nicely fill a post card. Still another suggestion is to cut out the letters, after, pasting the prints on some thin card, and then arrange them in the desired order to spell out the name or greeting, but with flowers interspersed and forming a background, photographing them down to the desired size.

A third means of securing a novel effect by photographing down an arrangement of the letters is to have them cut out in stiff form as in the last method; mount them on short pieces of corks, in turn fastened to a white card forming the background. So arranged, the letters will stand out from the card about 1/2 in. If they are now placed in a light falling from the side and slightly in front, each letter will cast a shadow upon the background, and in the finished print the letters will look as if suspended in the air in front of the surface of the card.

** Holding a Loose Screw [233]

A piece of sheet lead put on each side of a screw will fill up and hold the threads in a too large hole.

A Checker Board Puzzle [233]

Place eight checker men upon the checker board as shown in the first row in the sketch. The puzzle is to get

[Ill.u.s.tration: Placing the Checkers]

them in four piles of two men each without omitting to jump over two checker men every time a move is made.

The first move is to jump 5 over 4 and 3 on 2 which is shown in the second row, then jump 3 over 4 and 6 on 7 and the positions will appear as shown in the third row; jump 1 over 2 and 5 on 4 to get the men placed like the fourth row and the last move is to jump 8 over 3 and 7 on 6 which will make the four piles of two men each as shown in the fifth row.

--Contributed by I. G. Bayley, Cape May Point, N.J.

** A Home-Made Rabbit Trap [233]

[Ill.u.s.tration: Rabbit in the Trap]

A good serviceable rabbit trap can be made by sinking a common dry goods box in the ground to within 6 in. of its top. A hole 6 or 7 in. square is cut in each end level with the earth's surface and boxes 18 in. long that will just fit are set in, hung on pivots, with the longest end outside, so they will lie horizontal. A rabbit may now look through the two tubes, says the American Thresherman. The bait is hung on a string from the top of the large box so that it may be seen and smelled from the outside. The rabbit naturally goes into the holes and in this trap there is nothing to awaken his suspicion. He smells the bait, squeezes along past the center of the tube, when it tilts down and the game is shot into the pit, the tube righting itself at once for another catch. The top and sides of the large box may be covered with leaves, snow or anything to hide it. A door placed in the top will enable the trapper to take out the animals. By placing a little hay or other food in the bottom of the box the trap need not be visited oftener than once a week.

** Old-Time Magic - Changing a b.u.t.ton into a Coin [234]

Place a b.u.t.ton in the palm of the left hand, then place a coin between the second and third fingers of the right hand. Keep the right hand faced down and the left hand faced up, so as to conceal the coin and expose the b.u.t.ton. With a quick motion bring the left hand under the right, stop quick and

[Ill.u.s.tration: Making the Change]

the b.u.t.ton will go up the right-hand coat sleeve. Press the hands together, allowing the coin to drop into the left hand, then expose again, or rub the hands a little before doing so, saying that you are rubbing a b.u.t.ton into a coin.

--Contributed by L. E. Parker, Pocatello, Idaho.