The Boy Mechanic Part 85

To construct, layout the bases as shown in the drawing, making the mortises to receive the bottom ends of the posts exactly in the center, and cut a slanting mortise 6 in. from each end to receive the ends of the knee braces. Bevel the ends of the knee braces and fasten the upper ends of each pair to the post with one 9-in.

bolt. Fasten the lower ends to the base with the 7-in. bolts.

The upper end of each post should have 5/8-in. holes bored through it parallel to the base at intervals of 3 in., beginning 1-1/2 in.

from the top and extending down its length for 2 ft. 4-1/2 in. The adjusting pieces are to be bored in a similar manner after which they are to be mortised into the under side of the horse top 15 in. from each end, and secured with screws put through the top and into the end of the adjusting pieces.

The bases with their posts and knee braces are buried 2 ft. 4 in.

in the ground, parallel to each other and the same distance apart as the adjusting pieces are mortised in the horse top. When the ground has been filled in and tamped hard, the cross brace should be bolted in position with its lower edge resting on the ground and connecting the two posts.

The height of the horse from the ground is adjusted by changing the bolts in the different holes connecting the two adjusting pieces with the two posts. Much pleasant and healthful gymnastic exercise can be had in compet.i.tive horse jumping and leaping, the handles providing a way to make many different leaps through, over and around, including not only those made to see who can go over the horse from a standing or running start at the greatest height, but who can go over at the greatest height when starting from the "toeing off mark" farthest away from the horse. This horse should be located on level ground having smooth s.p.a.ce about it for several feet.

** Spoon Rest for Kettles [304]

A rest for keeping spoons from slipping into kettles can be made from

[Ill.u.s.tration: Spoon Rest]

a strip of metal bent as shown in the ill.u.s.tration. The spring of the metal will make it easy to apply to the kettle. The spoon placed in the rest will drain back into the kettle. The cover can be placed on without removing the spoon.

--Contributed by W. A. Jaquythe, Richmond. Cal.

** Reason for Bursting of Gun Barrels [304]

Gun barrels do not burst without a cause and usually that cause is one of which the shooter is entirely ignorant, but nevertheless, no one is responsible but himself, says the Sporting Goods Dealer.

Gun barrels can only burst by having some obstruction in the barrel or by overloading with powder. Any gun barrel can be burst by misuse or by carelessly loading smokeless powder, but no barrel will burst by using factory loaded ammunition, provided there is no obstruction or foreign substance inside the barrel. When a gun barrel bursts at the breech or chamber, it is caused by an overloaded sh.e.l.l, and when it bursts in the center or near the muzzle, it is caused by some obstruction, such as a dent, snow, water, etc.

** Hand Sled Made of Pipe and Fittings [305]

The accompanying sketch shows how an ordinary hand sled can be made of 3/4-in. pipe and fittings. Each runner is made of one piece of pipe bent to the proper shape. This can be accomplished by filling the pipe with melted rosin or lead, then bending to the shape desired, and afterward removing the rosin or lead by heating. Each joint is turned up tightly and well pinned or brazed. One of the top crosspieces should have right-hand and left-hand threads or be fitted with a union. Also, one of the top pieces connecting the rear part to the front part of each runner must be fitted in the same way. The top is fastened to the two crosspieces. Such a hand sled can be made in a

[Ill.u.s.tration: Parts Made of Pipe Fittings]

few hours' time and, when complete, is much better than a wood sled.

--Contributed by James E. n.o.ble, Toronto, Ontario.

** Emergency Magnifying Gla.s.s [305]

When in need of a microscope in the study of botany, one may be made in the following manner: Bend a small wire or the stem of a leaf so as to form a small loop not larger than the ordinary drop of water.

Loop Inclosing a Drop of Water

When this is done place a drop of clear water in the loop and the microscope is complete. This temporary device will prove valuable where a strong magnifying gla.s.s is not at hand.

--Contributed by Arthur E. Joerin, Paris, France.

** Bent-Iron Pipe Rack [305]

Strips of soft iron, 1/4 or 3/16 in. in width and 1/32 in.

thick, are used in

[Ill.u.s.tration: Design of a Rack]

making the pipe rack shown in Fig. 1. This material can be obtained from any local hardware dealer who carries bar iron in stock.

Draw a full-size sketch of the design on paper, then run a string over each part, which, when straightened out, will give the length. The scrolls are bent with a pair of round-nose pliers.

These, with a pair of flat-nose pliers, are all the tools necessary. The part for holding the pipes is shown in Fig. 2. The end elevation, at E and F, shows how the rack is fastened to the main frame of the rack.

--Contributed by J. W. Vener, Boston, Ma.s.s.

** To Clean Silver [305]

A good method to clean silver of any kind is to place the articles in an aluminum vessel and add a few pieces of zinc. Hot water is added and the silver boiled until clean. It is best to use soft water. The tarnish is removed by the electrolytic action of the zinc on the aluminum and the silver, and the latter will take on a bright l.u.s.ter. This method of cleaning will not injure oxidized or black silver, nor that which is partly oxidized.

** Sharpening Skates with a File [306

Two methods are shown in the sketches for filing skates-one for hollow filing and the other for filing flat

[Ill.u.s.tration: Filing a Flat Surface]

and straight across the blade. The method shown in Figs. 1 and 2 is for filing the blade flat. The device for holding the skates consists of a board on which four blocks, AA and BB, are nailed.

These blocks are fastened on the board in the relative positions of the heel and sole on a shoe. The skates are clamped on them in the same manner as on a shoe. A flat file is drawn across both blades of the skates as shown. After the roundness is cut down on the edges of the blades the skates are removed and the file is drawn along the sides to remove the

[Ill.u.s.tration: Filing a Curved Surface]

burr. Skates filed in this way have flat surfaces with sharp edges.

Some skaters like a hollow-ground skate and the method shown in Figs. 3 and 4 can be used for filing a slightly curved surface in the blade. A piece of tin or sheet metal is shaped over a round file as shown in Fig. 3. The manner of filing the curves is shown in Fig. 4. The piece of metal is held over the file and blade of the skate as the file is worked.

** Lines and Letters Made with a Carpenter's Pencil [306]

The sketch shows some unusual work made with a carpenter's pencil. If the flat lead is notched with a three-cornered file (Fig. 1), two parallel lines may be drawn at one stroke, or various rulings may be made, as shown in Fig. 2. Broad lines can be made, as shown in Fig. 3, or unequal widths as in Fig. 4.

[Ill.u.s.tration: Pencil Points and Their Work]

In Figs. 2, 5 and 6 are shown lines especially adapted for the bookkeeper or draftsman. If one lacks the ability to draw old English letters with a pen, the letters may be first drawn with a carpenter's pencil (Fig. 7) and the outlines marked with ink and finally filled in. Narrow lines are made with points cut as in Figs. 8 and 9. A little practice with the carpenter's pencil in making these letters will enable the student to finally produce them with the pen used for the purpose.