Moving Picture World (Mar-Dec 1907)

THE MOVING PICTURE WORLD. strip of gutta-percha sheeting six inches long by one inch wide and start (as in Fig. io) to wrap this around the center of the joint until you have Fig. 1 1 ; warm again until very soft and mould it down over the entire jpint, as shown in Fig. 12, making the finish as neat as possible. Remember that gutta-percha should not be heated too much or it will become very sticky ; if so, allow to cool slightly before proceeding. In jointing rubber-covered wires proceed as in Figs. 4, 5 and 6, but in this case cover with rubber strip, using rubber solution as an adhesive, brushing some more of the solution over the entire joint, including the covering on either side ; remember to use plenty of rubber tape. Then cover the entire joint with the black insulating tape, making sure to cover the joint and the covering on either side for at least two inches and then shellac varnish all over and allow to dry. In passing on to cables let me say that there are several ways of jointing cables and I am going to explain the best and simplest as well as those in most common use, although a man very often picks his own way out as the best one after all. It does not matter much, so long as his work holds the strain and has good electrical conductivity up to the requirements of the work it is called upon to perform. In jointing cables first proceed to strip off the insulation for about four inches each side of the joint ; then cut the bunch of wires on the slope (as shown in Fig. 13) called scarfing the wires (this can be done with the file) ; then clean all wires thoroughly, if necessary separating them apart to do so ; then either holding the two ends in a jointing vise, or by an assistant, proceed to solder them together, using your compound as before, being sure that the solder has run through all the wires forming the strands of the cable; then bind the joint with binding wire (as shown in Fig. i4), well covering the joint so as to add strength to it, and again solder the whole into one mass, thereby making a solid affair of the entire joint; clean off and proceed to cover with rubber tape (as shown in Fig. 15) ; then brush over the entire joint some of the rubber solution and allow to dry, which it does in a few minutes; then wrap the same again with rubber tape until you build it up, as shown in Fig. 16; again brush some more rubber solution to fill up the spaces around the tape and to ensure a satisfactory and tight joint; then cover the entire joint with insulating tape (as shown in Fig. 17), only trying to make as neat a joint as it is possible to make (there should only be the slightest possible swelling of the joint at this point, not even as much as shown in Fig. 17) ; then finish off with shellac varnish all over and allow to dry. The writer recommends that all beginners practice on short pieces of cable before tackling a regular job in this line so as to give confidence and the knack of going about the work. The best and strongest way to joint cables is to open ■out the strands, as shown in Fig. 18, clean each wire, 501 then place the two together until a wire of each cable lies in between one of the other cable and then start to twist one over the other till you have a locked joint (as in Fig. 19) with one cable well knitted over the other one ; then the lock is not only perfect, but it will withstand the strain better. Next apply your soldering compound and solder until the whole is united into a solid mass ; proceed to tape and cover as before, finishing up the entire work in like manner to the previous method. Fig. 20 shows a method of making a tee joint by opening out the strands of the cable to be attached, cleaning well and then separating into halves and laying the main cable in the middle, twisting the two halves around the main cable in each direction and solder, then covering and finishing as before. Fig. 21 shows two samples of Seeley’s connectors for cables which are very handy things to use for the purpose as well as allowing the making of a neater joint than some men can make. The first view is for tee joints and the second one is for straight joints. They are made of copper, well tinned, so that they solder well and are used (as in Fig. 22) by slipping over the wires and closing with the pliers and soldering, the solder running through the entire joint. Fig. 23 shows a simple method of making a tee joint in gutta-percha covered wires and consists of bending the wire to be connected at right angles and binding on with binding wire and soldering in the usual way; then cover as before. The last figures refer to lead-covered cables, as so commonly used now in large cities for feeders ; that is, the service mains that supply the electrical energy throughout the streets. In jointing these, take your cobbler’s knife, have it as sharp as you can get it, then wet it and proceed to cut the lead off on either side and proceed to joint as for an ordinary cable until you have the appearance of Fig. 24. First, before making your joint, get a piece of lead pipe slightly larger than the cable and slip it over the cable and keep it there while jointing and when the stage, as shown in Fig. 24, is reached, slip the lead pipe over the joint and proceed with melted lead to wipe the joint so as to make the lead pipe and the lead covering one entire mass, as shown in Fig. 25. I may here explain how to wipe a lead joint. First take a lamp black solution and paint the part of the cable covering where you do not wish the lead to adhere to ; then melt your lead and get it as hot as you can; when practically boiling, pour with a small ladle over the part to be joined using your hand, covered well with a leather glove or wiper of thick leather (the glove must be without fingers as a mitt), and as you pour the lead on wipe it around the joint so that the hot lead will melt and unite with the lead of the pipe and the cable covering. A little tallow rubbed Over the lead to be jointed helps to make it unite easily and keep on doing the pouring and wiping until you have a smooth, well-knit job. A little practice