The measurements here given need not be strictly followed out, but
can be governed by circumstances. The case should first be made
and varnished and while this is drying, the mechanical parts can
be put together.

[Illustration: Details of an Ammeter]

The back is a board 3/8 in. thick, 6-1/2 in. wide and 6-3/4 in.
long. The outer edges of this board are chamfered. The other parts
of the case are made from the cigar box wood which should be well
sandpapered to remove the labels. The sides are 3-1/4 in. wide and
5 in. long; the top and bottom, 3-1/4 in. wide and 4-1/2 in. long.
Glue a three cornered piece, A, Fig. 1, at each end on the surface
that is to be the inside of the top and bottom pieces. After the
glue, is set, fasten the sides to the pieces with glue, and take
care that the pieces are all square. When the glue is set, this
square box is well sandpapered, then centered, and fastened to the
back with small screws turned into each three-cornered piece.

The front, which is a piece 5-1/4 in. wide and 6-1/2 in. long, has
a circular opening cut near the top through which the graduated
scale may be seen. This front is centered and fastened the same as
the back, and the four outside edges, as well as the edges around
the opening, are rounded. The whole case can now be cleaned and
stained with a light mahogany stain and varnished. Cut another
piece of board, B, Figs. 2 and 3, to just fit inside the case and
rest on the ends of the three-cornered pieces, A, and glue to this
board two smaller pieces, C, 3 in. square, with the grain of the
wood in alternate directions to prevent warping. All of these
pieces are made of the cigar box wood. Another piece, D, 3/8 in.
thick and 3 in. square, is placed on the other pieces and a
U-shaped opening 1-3/4 in. wide and 2-1/2 in. high sawed out from
all of the pieces as shown. The piece D is attached to the pieces
C with four 1/2-in. pieces 2-5/8 in. long.

A magnet is made from a soft piece of iron, E, about 3/8 in.
thick, 1-1/4 in. wide and 2-3/4 in. long. Solder across each end
of the iron a piece of brass wire, F, and make a turn in each end
of the wires, forming an eye for a screw. These wires are about
2-1/2 in. long. Wind three layers of about No. 14 double
cotton-covered copper wire on the soft iron and leave about 5 or 6
in. of each end unwound for connections.

The pointer is made as shown in Fig. 5 from 1/16-in. brass wire
filed to make a point at both ends for a s