��ropular Science Alonthly
��©-Wi'/Vra.'©*''*^ ■*'«'©*«?/ WPirasj
���■ . ¥ I — V-
���© <te«? / / nararvBlicr or/ier Ixm
��Diagrams of the other details of the battery
��Detail 8 represents the interior or contact panel which is best made of fiber.
The contact slip-ring for the testing- switch is shown at 9; 10 shows the stop-pins for both switches.
The spring ( 1 1) which keeps the testing- switch contact arms out of contact with the points, is clearly shown in Fig. 7.
The locating spring (12) for'the testing- switch, is also clearly shown in Fig. 7.
Details I3and I4aretheswitcharniancl friction springfor the high-tension switch.
Detail 15 shows the centers of both switches, and 16 represents the adjusting collars for them.
The bushings (17) for the switches, should be forced in place in the hard rubber front panel.
Detail 18 is of the socket and flange for the testing-lamp. Thisismadel)\' takinga
���A complete wiring diagram of the battery
��"pin-socket," procured from an electrical supply house, and making a flange as shown. The socket is then soldered into a hole in the flange and filed down neatly, making finally a flush socket.
The hard rubber knob for the high-tension switch is shown at 19, the contact springs for the testing-switch at 20. These springs are cut exactly as shown and bent to suit.
The contacts for the cells (21), should be of very springy material and like the other parts, are preferably nickel-plated in order to pre- vent corrosion.
Detail 22 is of the hard rubber knob for the testing- switch and is drilled around its periphery to accomodate in the proper positions the friction spring shown in detail 12. It is suggested that the locating holes be not drilled until the switch is assembled, as this insures a much more accurate arrangement of the holes.
In assembling, the battery box is first set up and the fiber panel screwed on after having the contact-springs and points mounted on it. Then the fiber separators are pushed into place. The next step is to assemble the switch panel and mount it on its wood supporting top. The switch-points used are stan- dard X if- by X i"- heads having an 8-32 screw-hole at the back. The connecting wires at the back arc best soldered into small holes drilled into the screws. The connections to the battery contact points on the fiber panel are also preferably soldered into holes in the end of the screw shanks, these points being the usual type. The batteries used are the No. 603 pocket flashlight cell. The length of the battery box given in the drawings allows y^ in. for each cell but it may be best to measure up a set of cells and by dividing the total length covered by the number of cells obtain a fair average.
The pointsof the testing-switch and cell conii)artinents should he nuniiiered, so that a defective (cll ma>- be jiicked out immeiliately.