The Boy Mechanic Part 99

** How To Build An Ice Boat [357]

The ice boat is each year becoming more popular. Anyone with even small experience in using tools can

[Ill.u.s.tration: A Four-Runner Ice Yacht]

construct such a craft, and the pleasure many times repays the effort.

Take two pieces of wood 2 by 6 in., one 6 ft. and the other 8 ft.

long. At each end of the 6-ft. piece and at right angles to it, bolt a piece of hardwood 2 by 4 by 12 in. Round off the lower edge of each piece to fit an old skate. Have a blacksmith bore holes through the top of the skates and screw one of them to each of the pieces of hardwood.

[Ill.u.s.tration: Plan of Ice Boat]

These skates must be exactly parallel or there will be trouble the first time the craft is used.

Over the middle of the 6-ft. piece and at right angles to it, bolt the 8-ft. plank, leaving 1 ft. projecting as in Fig. 1.

The rudder skate is fastened to a piece of hardwood 2 by 2 by 12 in. as the runners were fastened. This piece should be mortised 3 by 3 by 4 in. in the top before the skate is put on. Figure 2 shows the rudder post.

A piece of hardwood 1 by 6 by 6 in.

[Ill.u.s.tration: Details of Ice Boat Construction]

should be screwed to the under side of the 8-ft. plank at the end with the grain running crosswise. Through this bore a hole 1-1/2-in. in diameter in order that the rudder post may fit nicely. The tiller, Fig. 3, should be of hardwood, and about 8 in.

long.

To the under side of the 8-ft. plank bolt a piece of timber 2 by 4 by 22 in. in front of the rudder block, and to this cross piece and the 6-ft. plank nail 8-in. boards to make the platform.

The spar should be 9 ft. long and 2-1/2 in. in diameter at the base, tapering to 1-1/2 in. at the top. This fits in the square hole, Fig. 1. The horn should be 5-1/2 ft. long, 2 by 3 in. at the b.u.t.t and 1 in. at the end.

Figure 4 gives the shape and dimensions of the mainsail which can be made of muslin. Run the seam on a machine, put a stout cord in the hem and make loops at the corners.

Figure 6 shows the way of rigging the gaff to the spar. Figure 7 shows the method of crotching the main boom and Fig. 8 a reef point knot, which may come in handy in heavy winds.

Make your runners as long as possible, and if a blacksmith will make an iron or steel runner for you, so much the better will be your boat.

** Electric Rat Exterminator [358]

Some time ago we were troubled by numerous large rats around the shop, particularly in a storehouse about 100 ft. distant, where they often did considerable damage. One of the boys thought he would try a plan of electrical extermination, and in order to carry out his plan he picked up an old zinc floor plate that had been used under a stove and mounted a wooden disk 6 in. in diameter in the center. On this disk he placed a small tin pan about 6 in. in diameter, being careful that none of the fastening nails made an electrical connection between the zinc plate and the tin pan.

This apparatus was placed on the floor of the warehouse where it was plainly visible from a window in the shop where we worked and a wire was run from the pan and another from the zinc plate through the intervening yard and into the shop. A good sized induction coil was through connected with these wires and about six dry batteries were used to run the induction coil whenever a push b.u.t.ton was manipulated.

It is quite evident that when a rat put its two fore feet on the edge of the pan in order to eat the mush which it contained, that an electrical connection would be made through the body of the rat, and when we pushed the b.u.t.ton up in the shop the rat would be thrown

[Ill.u.s.tration: Electric Rat Trap]

2 or 3 ft. in the air and let out a terrific squeak. The arrangement proved quite too effective, for after a week the rats all departed and the boys all regretted that their fun was at an end.

--Contributed by John D. Adams, Phoenix, Ariz.

** How to Make a Simple Fire Alarm [359]

A fire alarm which is both inexpensive and simple in construction is shown in the ill.u.s.tration. Its parts are as follows:

A, small piece of wood; B, block of wood nailed to A; S S. two pieces of sheet bra.s.s about 1/4 in. wide, bent into a hook at each end; P, P, binding-posts fastening the springs S S, to block B, so that they come in contact at C. W is a piece of wax crayon just long enough to break the contact at C when inserted as shown in the ill.u.s.tration.

When these parts have been put together in the manner described, connect the device in circuit with an electric bell, and place it behind a stove.

[Ill.u.s.tration: Simple Fire Alarm]

When the stove becomes too hot the wax will melt at the ends, allowing the springs to contact at C, and the alarm bell will ring.

--Contributed by J. R. Comstock, Mechanicsburg, Pa.

** To Build a Merry-Go-Round [359]

This is a very simple device, but one that will afford any amount of amus.e.m.e.nt. The center post rests in an auger hole bored in an old stump or in a post set in the ground. The stump makes the best support. The center pole should be 10 ft. high. An old wheel is mounted at the top of the pole, and the pole works in the wheel as an axle, says the American Boy. The wheel is anch.o.r.ed out by several guy

[Ill.u.s.tration: Home-Made Merry-Go-Round]

wires. The seat arms may be any length desired. A pa.s.senger rides in each seat and the motorman takes his station at the middle.

** Arbor Wheels [359]

Emery wheel arbors should be fitted with f.l.a.n.g.es or washers having a slight concave to their face.

** Novelty Clock for the Kitchen [360]

An inexpensive and easy way to make an unique ornament of a clock

[Ill.u.s.tration: The Clock with Holder]

for kitchen use is to take an old alarm clock or a new one if preferred, and make it into a clock to hang on the wall. Take the gla.s.s, dial and works out of the sh.e.l.l and cut some pieces out of the metal so that when the pieces left are turned back it will have the appearance as in Fig. 1. Then get a 10-cent frying pan, 6 in. in diameter, and drill a hole in the center so the shaft for the hands will easily pa.s.s through and extend out far enough to replace the two hands. Put the works back in the metal sh.e.l.l and solder it to the frying pan by the pieces turned out as in Fig. 2.

Gild the pan all over, including the handle, and print black figures in the small circles. Calendar figures can be pasted on small circles and these pasted on the frying pan. The parts can be divided into minutes with small lines the same as shown in the drawing. Make new hands that are long enough to reach the figures from sheet bra.s.s or tin and paint them black.

--Contributed by Carl P. Herd, Davenport, Iowa

** How to Make a Small Silver Plating Outfit [360]