Part 3 (1/2)

Hold the yoke as in App 79 or 80 for filing As you will probably have no anvil, lay an old nut from a bolt upon the end of the block of wood (App 26), place the ine that you have an anvil Very good results may be obtained by this method The size of nut used will depend upon the size of hole wanted

APPARATUS 28

_43 To Straighten Wires_ It is often necessary to have short lengths of wires straight, where they are to be hten them, lay one or two at a time upon a perfectly flat surface, place a flat piece of board upon them, then roll them back and forth between the two The upper board should be pressed down upon the wires while rolling theht as needles

_44 Push-buttons_ Nearly every house has use for one or er upon aa bell a

APPARATUS 29

_45 Push-button_ Fig 14 This is made quickly, andOne wire is joined to A and the other to C B is a strip of tin or otherIt is bent so that it will not touch A unless it is pressed down This may be placed anywhere, in an electric-bell circuit or other open circuit, where it is desired to let the current pass for a14]

APPARATUS 30

_46 Push-button_ Fig 15 and Fig 16 By placing App 29 in a box, we canthat looks a little15 shows a plan with the box-cover re 16 shows a view of the inside of it, a part of the box being cut away C, Fig 15, is a wooden pill-box 1 in high and 1-3/4 in in diameter Make a 1/4 in hole in the cover of C for the ”button,” G, which is a short piece of 1/4 in dowel This rests upon a single thickness of tin, D, which is cut into a strip 3/8 in wide and about 1-1/4 in long In the bottoh to allow the screws E and F to pass through The wires, A and B, pass froh sh the sides of the box, and are fastened under the screw-heads The whole box is screwed to the wooden base, which is 3 4 7/8 in, by the screws, E and F D should have enough spring in it to raise itself and G when the pressure of the finger is removed The circuit will be closed only when you press the button

[Illustration: Fig 15]

[Illustration: Fig 16]

APPARATUS 31

_47 Push-button_ Figs 17, 18, 19 Fig 17 shows a top view or plan of the apparatus Fig 18 is a sectional view; that is, we suppose that the button has been cut into two parts along its length and through the center line Fig 19 is an enlarged detail drawing of the underside of the spool, C The saures

[Illustration: Fig 17]

[Illustration: Fig 18]

[Illustration: Fig 19]

Saw an ordinary spool, C, into two parts One-half of C will serve as the outside case for the button The part to be pressed with the finger is a short length of 1/4 in dowel To keep this fro out of the hole in C, a short piece of wire nail, N, has been put through a small hole in its lower end A slot, F, has been burned or cut into the underside of C, so that N can pass up and down in it when D is raised and lowered The rod, D, rests upon A, one of the contacts This is a straight piece of tin, cut as shown in Fig 17, the narrow part being 1/4 in wide and 1-1/4 in long The wide part is 3/4 in wide and 1 in

long The other contact, B, is the saroove, a little over 1/4 in wide, is cut into the base so that the narrow part of B can be bent down below the end of A The base shown is 4 2-1/2 7/8 in The spool, C, is fastened to the base by 2 screws or wire nails put up through the base, their positions being shown by the dots at E, Fig 17 X and Y, Fig 18, are 2 screw binding-posts It is evident that the current cannot pass from X to Y, unless the button, D, be pressed down so that the end of A will touch B

APPARATUS 32

_48 Sifter for Iron Filings_ Fig 20 In e to have the particles of iron fairly small and unifor holes in the bottom of a pasteboard pill-box with a pin The sifter s in it, provided you turn it upside down

[Illustration: Fig 20]

APPARATUS 33

_49 Sifter for Iron Filings_ Fig 21 Punch small holes in the cover of a tin box with a small wire nail If you have occasion to use sifters for other purposes, the different sizes can be er and smaller nails to punch the different tin covers But one size of nail should be used for one sifter