The Boy Mechanic Part 61

[Ill.u.s.tration: Machine Belted to the Motorcycle]

** Home-Made Aquarium [219]

A good aquarium can be made from a large-sized street lamp globe and a yellow pine block. Usually a lamp globe costs less than an aquarium globe of the same dimensions. Procure a yellow pine block 3 in. thick and 12 in. square. The more uneven and twisted the grain the better for the purpose,

[Ill.u.s.tration: Lamp Globe as an Aquarium]

it is then less liable to develop a continuous crack.

Cut out a depression for the base of the globe as shown in Fig. 1.

Pour in aquarium cement and embed the globe in it. Pour more cement inside of the globe until the cement is level with the top of the block. Finish with a ring of cement around the outside and sprinkle with fine sand while the cement is damp. Feet may be added to the base if desired. The weight of the pine block makes a very solid and substantial base for the globe and renders it less liable to be upset.

--Contributed by James R. Kane, Doylestown, Pa

** Protect Your Lathe [219]

Never allow lard oil to harden on a lathe.

** Frame for Displaying Both Sides of Coins [220]

It is quite important for coin collectors to have some convenient way to

[Ill.u.s.tration: Holding Coins between Gla.s.ses]

show both sides of coins without touching or handling them. If the collection consists of only a few coins, they can be arranged in a frame as shown in Fig. 1. The frame is made of a heavy card, A, Fig. 2, the same thickness as the coins, and covered over on each side with a piece of gla.s.s, B. Holes are cut in the card to receive the coins C. The frame is placed on bearings so it may be turned over to examine both sides. If there is a large collection of coins, the frame can be made in the same manner and used as drawers in a cabinet. The drawers can be taken out and turned over.

--Contributed by C. Purdy, Ghent, O.

** How to Make Lantern Slides [220]

A great many persons who have magic lanterns do not use them very much, for after the slides have been shown a few times, they become uninteresting, and buying new ones or even making them from photographic negatives is expensive. But by the method described in the following paragraph anyone can make new and interesting slides in a few minutes' time and at a very small cost.

Secure a number of gla.s.s plates of the size that will fit your lantern and clean them on both sides. Dissolve a piece of white rosin in a half-pint of gasoline and flow it over one side of the plates and allow to dry. Place the dried plate over a picture you wish to reproduce and draw the outline upon the thin film. A lead pencil, pen and ink or colored crayons can be used, as the rosin and gasoline give a surface that can be written upon as easily as upon paper. When the slide becomes uninteresting it can be cleaned with a little clear gasoline and used again to make another slide.

A slide can be made in this way in five minutes and an interesting outline picture in even less time than that.

This solution also makes an ideal retouching varnish for negatives.

--Contributed by J.E. n.o.ble, Toronto, Canada.

** How to Make a Developing Box [220]

A box for developing 3-1/4 by 4-1/4 -in. plates is shown in detail in the accompanying sketch. It is made of strips of wood 1/4-in.

thick, cut and grooved, and then glued together as indicated. If desired, a heavier piece can be placed on the bottom. Coat the inside of the box with paraffin or wax, melted and applied with a brush. Allow it to fill all crevices so that the developing box will be watertight. It will hold 4 oz. of developer. Boxes for larger plates

[Ill.u.s.tration: Details of the Developing Box]

can be made in the same manner. Use a small wooden clip in taking the plates out of the box, being careful not to scratch the sensitive film.

--Contributed by R.J. Smith, Milwaukee, Wis.

** Staining Wood [221]

A very good method of staining close-grained woods is to use muriatic acid. The acid is put on with a brush like any ordinary stain. The colors thus obtained are artistic and most beautiful, and cannot be duplicated by any known pigment. The more coats applied the darker the color will be. This method of staining has the advantage of requiring no wiping or rubbing.

--Contributed by August T. Neyer, One Cloud, Cal.

** Sheet-Metal Whisk-Broom Holder [221]

A whisk-broom holder such as is shown in the accompanying picture may be easily made by the amateur. The tools needed are few: a pair of tin shears, a metal block of some kind upon which to pound when riveting, a hammer or mallet, several large nails, and a stout board upon which to work up the design. A rivet punch is desirable, though not absolutely necessary.

The material required is a sheet of No. 24 gauge copper or bra.s.s of a size equal to that of the proposed holder, plus a 3/8-in.

border all around, into which to place the screws that are to be used to hold the metal to the board while pounding it. The design shown in the picture is 6 by 8 in. at the widest part and has proven a satisfactory holder for a small broom.

Carefully work out the design desired on a piece of drawing paper, both outline and decoration, avoiding sharp curves in the outline because they are hard to follow with the shears when cutting the metal. If the design is to be of two-part symmetry, like the one shown, draw one part, then fold on a center line and duplicate this by inserting double-surfaced carbon paper and tracing the part already drawn. With this same carbon paper transfer the design to the metal. Fasten the metal to the board firmly, using 1/2-in. screws placed about 1 in. apart in holes previously punched in the margin with a nail set or nail.

To flatten the metal preparatory to fastening it to the board, place a block of wood upon it and pound on this block, never upon the metal directly,

[Ill.u.s.tration: Completed Holder Bra.s.s Fastened to Board-Method of Riveting]

or the surface will be dented and look bad in the finished piece.

Take the nail, a 10 or 20-penny wire or cut, and file it to a chisel edge, rounding it just enough to take the sharpness off so that it will not cut the metal. This tool is used for indenting the metal so as to bring out the outline of the design on the surface.

There are several ways of working up the design. The simplest way is to take the nail and merely "chase" the outlines of holder design. Remove the screws, cut off the surplus metal and file the edges until they are smooth. Make a paper pattern for the metal band that is to hold the broom. Trace around this pattern on the metal and cut out the shape. Punch rivet holes in holder and band, also a hole by which to hang the whole upon the wall.

Rivet the band to the holder. Punch the rivet holes with a nail set and make the holes considerably larger than the diameter of the rivet, for in flattening the raised edges the holes will close. Do the riveting on a metal block and keep the head of the rivet on the back of the holder. Round up the "upset" end of the riveted part as shown in the picture. Do not bend it over or flatten it. This rounding is done by pounding around the outer edge of the rivet end and not flat upon the top as in driving a nail.

Clean the metal by scrubbing it off with a solution composed of one-half water and one-half nitric acid. Use a rag tied to a stick and do not allow the acid to touch either your hands or clothes. A metal lacquer may next be applied to keep the metal from early corrosion.

** How to Make a Camp Stool [222]

The stool, as shown in Fig. 1, is made of beech or any suitable wood

[Ill.u.s.tration: Camp Stool Details]

with a canvas or carpet top. Provide four lengths for the legs, each 1 in. square and 18-1/2 in. long; two lengths, l-1/8 in.

square and 11 in. long, for the top, and two lengths, 3/4 in.

square, one 8-1/2 and the other 10-1/2 in. long, for the lower rails.