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 spindle.  About 1/2 in. from each end of this wire are soldered two smaller brass wires which in turn are soldered to a strip of light tin 1/4 in. wide and 2-5/8 in. long.  The lower edge of this tin should be about 1/2 in. from the spindle.  The pointer is soldered to the spindle 1/4 in. from one end.  All of these parts should be brass with the exception of the strip of tin.  Another strip of tin, the same size as the first, is soldered to two brass wires as shown in Fig. 4.  These wires should be about 1 in. long.