The Boy Mechanic Part 75

** Method of Joining Boards [268]

The amateur wood-worker often has trouble in joining two boards together so that they will fit square and tight. The accompanying sketch shows a simple and effective method of doing this. Secure a board, A, about 12 in. wide that is perfectly flat. Fasten another board, B, about 6 in. wide, to the first one with screws or glue.

Now place the board to be joined, C, on the board B, letting it extend over the inside edge about 1 in. and fastening it to the others with clamps at each end. Lay the plane on its side and plane the edge straight. Place the second board in the clamps in the same manner as the first, only have the opposite side up. If the cutting edge of the blade is not vertical, the boards planed in this manner will fit as shown in the upper sketch. In using this method, first-cla.s.s joints can be made without much trouble.

--Contributed by V. Metzech, Chicago.

[Ill.u.s.tration: Joining Boards]

** Toy Gun for Throwing Cardboard Squares [269]

The parts of the gun are attached to a thin piece of wood 1 in.

wide and 5 in. long. It is best to use a piece of wood cut from the side or cover of a cigar box. A rectangular hole 3/16 in. wide and 1 in. long is cut in the wood longitudinally along its axis and 1-3/8 in. from one end, as shown at A, Fig. 1. A small notch is made with the point of a knife blade at B and notches are cut in the end of the wood as shown at C. Rubber bands are fastened in these notches as shown in Fig. 2. The trigger, whose dimensions are given in Fig. 3, is fastened in the hole A, Fig. 1, by driving a pin through the wood. The a.s.sembled parts are shown in Fig. 4.

Place the cardboard square in the nick B, attach the rubber bands and pull the trigger. The top rubber band will fly off and drive the cardboard

[Ill.u.s.tration: Details of Toy Gun]

square 75 ft. or more. The cardboard should be about 1/2 in.

square. These can be cut from any old pasteboard box.

--Contributed by Elmer A. Vanderslice, Phoenixville, Pa.

** Photographic Developing Tray [269]

Plates developed in an ordinary tray must be removed from the bath occasionally for examination. The film when in a chemical-soaked condition is easily damaged. The tray ill.u.s.trated herewith was made for the purpose of developing plates without having to take hold of them until the bath had completed its work, the examination being made through the plate and the bottom of the tray.

A pocket is provided for the liquid developer in one end of the tray when it

[Ill.u.s.tration: Developing Tray with Gla.s.s Bottom]

is turned up in a vertical position. A tray for developing 5 by 7-in. plates should be made 8 in. square inside. The side pieces with the grooves for the gla.s.s are shown in Fig. 1. Two of each of these pieces are made with mitered ends. The short groove shown in the top piece of the ill.u.s.tration is for inserting the plate covering on the pocket end of the tray.

Two blocks, one-half the length of the side pieces, are put in between the gla.s.s plates to hold the plate being developed from dropping down when the tray is tipped up in a vertical position.

The gla.s.s bottom of the tray is 8-1/2 in. square, which allows 1/4 in. on all edges to set in the grooves of the side pieces. The wood pieces should be well soaked in hot paraffin, and the mitered corners well glued and nailed.

--Contributed by J.A. Simonis, Fostoria, Ohio.

** Iron Putty [269]

A good filler used as a putty on iron castings may be made as follows: Take, by weight, 3 parts of stiff keg lead, 5 parts of black filler, 2 parts of whiting, 5 parts of pulverized silica and make into a paste with a mixture of one part each of coach j.a.pan, rubbing varnish and turpentine.

** Rubber Bands in Kite Balancing Strings [270]

Kite flyers will find it to their advantage to place rubber bands of

[Ill.u.s.tration: Bands in String]

suitable size in the balancing strings to the kite, as shown in the ill.u.s.tration. This will prevent a "break-away" and also make the right pull, if only two bands are put in the lower strings.

--Contributed by Thos. DeLoof, Grand Rapids, Michigan.

** An Aid in Sketching [270]

Sketching requires some little training, but with the apparatus here ill.u.s.trated an inexperienced person can obtain excellent results. The apparatus is made of a box 8 in. deep, 8 in. wide and about 1 ft. long. A double convex lens, G, is fitted in a bra.s.s tube which should have a sliding fit in another shorter and larger tube fastened to the end of the box. A mirror, II, is set at an angle of 45 deg.

[Ill.u.s.tration: Sketching Aid]

in the opposite end of the box. This reflects the rays of light pa.s.sing through the lens to the surface K, which may be either of ground or plain gla.s.s. The lid or cover EF protects the gla.s.s and keeps the strong light out when sketching. The inside of the box and bra.s.s tube are painted a dull black.

In use, the device is set with the lens tube directed toward the scene to be painted or sketched and the lens focused so the reflected picture will be seen in sharp detail on the gla.s.s.

Select your colors and put them on the respective colors depicted on the gla.s.s. If you wish to make a pencil drawing, all you have to do is to fill in the lines in the picture on the ground gla.s.s.

If a plain gla.s.s is used, place tracing paper on its surface, and the picture can be drawn as described.

** How to Make Miniature Electric Lamp Sockets [270]

A socket for a miniature lamp can be made as shown in the sketch.

A bra.s.s spring wire is wound around the base of the threads on the lamp and an eye turned on each end to receive a screw and a binding-post, as shown in Fig. 1. A piece of metal, preferably copper, is attached to a wood base as shown in Fig. 2 and the coil-spring socket fastened across it in the opposite direction.

Bend the wire so that the spring presses the lamp against the metal. If the wire fits the lamp loosely, remove the lamp and press the sides of the coil closer together. The metal parts can

[Ill.u.s.tration: Wire Socket]

be attached to any smooth surface of wood without making a regular base.

--Contributed by Abner B. Shaw, No. Dartmouth, Ma.s.s.

** Imitation Arms and Armor-Part V [271]

The preceding chapters gave descriptions of making arms in imitation of ancient weapons, and now the amateur armorer must have some helmets to add to his collection. There is no limit to the size of the helmet, and it may be made as a model or full sized. In constructing helmets, a ma.s.s of clay of any kind that is easily workable and fairly stiff, is necessary, says the English Mechanic, London. It must be kept moist and well kneaded. A large

[Ill.u.s.tration: Making the Clay Model and Three Helmet Designs]

Board or several planks, joined closely together, on which to place the clay, will be necessary. The size of this board will depend on the size of the work that is intended to be modeled upon it.

The way to make a helmet is described in the following method of producing a German morion, shown in Fig. 1. This helmet has fleur-de-lis in embossed work, and on each side is a badge of the civic regiment of the city of Munich. The side view of the helmet is shown in Fig. 1.

The clay, is put on the board and modeled into the shape shown in Fig. 2. This is done with the aid of a pair of compa.s.ses, a few clay-modeling tools, and the deft use of the fingers. The fleur-de-lis are slightly raised, as in bas-relief. To aid in getting the helmet in correct proportion on both sides, and over the crest on top, cut out the shape from a piece of wood, as shown in Fig. 3, with a keyhole saw. This wood being pa.s.sed carefully and firmly over the clay will bring it into shape, and will also show where there may be any deficiencies in the modeling, which can then be easily remedied by adding more clay. The cut-out pattern shown in Fig. 4 is the side outline of the helmet.

Sc.r.a.ps of thin, brown, wrapping paper are put to soak in a basin of water to which has been added about a tablespoonful of size melted and well stirred, or some thin glue, and left over night to soak. The paper should be torn in irregular shapes about as large as the palm of the hand. After the clay model is finished, give it a thin coat of oil-sweet or olive oil will answer the purpose very well. All being ready, the clay model oiled, and the basin of soaked paper near to hand, take, up one piece of paper at a time and very carefully place it upon the model, pressing it well on the clay and into and around any crevices and patterns, and continue until the clay is completely covered.