Electricity for Boys | Page 6

blade; small iron square; pair of dividers; tin shears; wire cutters; 2 pairs of pliers, one flat and the other round-nosed; 2 awls, centering punch, wire cutters, and, finally, soldering tools.
[Illustration: Fig. 2. Top View MAGNET-WINDING REEL]
[Illustration: Fig. 3. Side View MAGNET-WINDING REEL]
If a gas stove is not available, a brazing torch is an essential tool. Numerous small torches are being made, which are cheap and easily operated. A small soldering iron, with pointed end, should be provided; also metal shears and a small square; an awl and several sizes of gimlets; a screwdriver; pair of pliers and wire cutters.
From the foregoing it will be seen that the cost of tools is not a very expensive item.
This entire outfit, not including the anvil and vise, may be purchased new for about $20.00, so we have not been extravagant.
MAGNET-WINDING REEL.--Some little preparation must be made, so we may be enabled to handle our work by the construction of mechanical aids.
[Illustration: Fig. 4. Journal Block.]
First of these is the magnet-winding reel, a plan view of which is shown in Fig. 2. This, for our present work, will be made wholly of wood.
Select a plank 1-1/2 inches thick and 8 inches wide, and from this cut off two pieces (A), each 7 inches long, and then trim off the corners (B, B), as shown in Fig. 4. To serve as the mandrel (C, Fig. 2), select a piece of broomstick 9 inches long. Bore a hole (D) in each block (A) a half inch below the upper margin of the block, this hole being of such diameter that the broomstick mandrel will fit and easily turn therein.
Place a crank (E), 5 inches long, on the outer end of the mandrel, as in Fig. 3. Then mount one block on the end of the bench and the other block 3 inches away. Affix them to the bench by nails or screws, preferably the latter.
On the inner end of the mandrel put a block (F) of hard wood. This is done by boring a hole 1 inch deep in the center of the block, into which the mandrel is driven. On the outer face of the block is a square hole large enough to receive the head of a 3/8-inch bolt, and into the depression thus formed a screw (G) is driven through the block and into the end of the mandrel, so as to hold the block (F) and mandrel firmly together. When these parts are properly put together, the inner side of the block will rest and turn against the inner journal block (A).
The tailpiece is made of a 2" �� 4" scantling (H), 10 inches long, one end of it being nailed to a transverse block (I) 2" �� 2" �� 4". The inner face of this block has a depression in which is placed a V-shaped cup (J), to receive the end of the magnet core (K) or bolt, which is to be used for this purpose. The tailpiece (H) has a longitudinal slot (L) 5 inches long adapted to receive a 1/2-inch bolt (M), which passes down through the bench, and is, therefore, adjustable, so it may be moved to and from the journal bearing (A), thereby providing a place for the bolts to be put in. These bolts are the magnet cores (K), 6 inches long, but they may be even longer, if you bore several holes (N) through the bench so you may set over the tailpiece.
With a single tool made substantially like this, over a thousand of the finest magnets have been wound. Its value will be appreciated after you have had the experience of winding a few magnets.
ORDER IN THE WORKSHOP.--Select a place for each tool on the rear upright of the bench, and make it a rule to put each tool back into its place after using. This, if persisted in, will soon become a habit, and will save you hours of time. Hunting for tools is the unprofitable part of any work.
CHAPTER III
MAGNETS, COILS, ARMATURES, ETC.
THE TWO KINDS OF MAGNET.--Generally speaking, magnets are of two kinds, namely, permanent and electro-magnetic.
PERMANENT MAGNETS.--A permanent magnet is a piece of steel in which an electric force is exerted at all times. An electro-magnet is a piece of iron which is magnetized by a winding of wire, and the magnet is energized only while a current of electricity is passing through the wire.
ELECTRO-MAGNET.--The electro-magnet, therefore, is the more useful, because the pull of the magnet can be controlled by the current which actuates it.
The electro-magnet is the most essential of all contrivances in the operation and use of electricity. It is the piece of mechanism which does the physical work of almost every electrical apparatus or machine. It is the device which has the power to convert the