The tool should be entered at O, in Fig. 78, and worked gradually toward A; when the point is raised to A clear across the belt, open on down to C. After both ends of the splice have been opened up in this way, proceed to open the middle, which is now an easy task, there being no thin stock that a separating tool will pass through easily. After the belt is entirely apart tighten up on the rods until the belt is the proper tension and hang the hooks (76b, Fig. 75) on the belt rods. Throw the two ends of the belt back over the clamp and put the splicing board in position. After this is in place, throw the two ends of the belt back on the board and proceed to lay off the scarfs. To do this, first take a square and get the two thin points perfectly square, then put the "first end" point in between them. This is shown very clearly in Fig. 77, the shaded end being the last end. Of course the "first end" point at C, Fig. 77, will have to be cut off before the belt will lie down properly; the amount to cut off of this end will be just as much as you have shortened the distance between the clamps. After the point has been cut to the right length, take the square and make a mark across the belt, using the end of the thin point as your measure for length; then without moving the belt make a mark on the edge of the belt, showing just where the lower thin point came on the bottom. Throw the "last end" over the left-hand clamp out of the way and scarf down the top of the "first end" point, letting the scarf be about 4 inches long. Be careful not to gouge a hole in the belt where the scarf is started, but try to make the inclined plane from X to X perfect; try to keep the whole surface of this incline true and straight. After the short 4-inch scarf is finished, clean the glue off of the inside of the "first end"; lap up to where it enters the "last end"; then turn it over by bringing it over the right-hand clamp, place a scarfing board under it and make the scarf shown at T, Fig. 75. Now clean all glue off the "last end" lap and take a sharp scraper like the one shown in Fig. 69 or 69b, place a piece of glass under the points that have been previously squared up, and scarf them down to a knife-edge.
After the thin points are properly scarfed, lay the whole splice back on the splicing board just as it will be when it is glued, and do any fitting that may be necessary. Be very careful to get it thin enough, or it will make a hammering noise when going over the pulleys. When scarfing down the thin points with the scrapers, be sure that they are very sharp; if not, they will tear the point off when it gets down to an edge; also give the blade a drawing motion in order to facilitate cutting. It may seem to the novice that to use a piece of glass to scarf on, when one is using a tool with a razor edge, is a trifle inconsistent, but it is not so in the least; if the blade is held well back at the top and a considerable pressure applied to it, there will be no danger in the edge actually touching the glass; the edge is turned past a right-angular position, or hooked, and the heel is all that touches the glass. A good piece of plate glass about 12 Ã 18 inches is large enough for any width of belt, although a piece much smaller will do all right. Do not attempt to do any scarfing on the board 76d, for if you do it will be so full of holes that have been gouged by the scraper that it will be ruined for any purpose.
This board must be kept smooth in order to be able to do a good job of rubbing down when gluing. Never hammer a glue joint in order to set it; it is just that much unnecessary work and does absolutely no good; simply get a smooth block of wood 2 Ã 6 Ã 8 inches and rub hard and fast as soon as the glue is applied. Do not try to glue more than 6 inches in length at one time. Use a heavy brush—a high-priced paint brush is the best; the regular glue brush is about the only thing in existence that will not put on any glue at all—about a 3-inch brush is the thing; have the glue just as hot as it is possible to get it. Keep the brush in the pot all the time the glue is heating; also have a strong stick made somewhat like a three-cornered file, only larger, in the glue—this last is used to scrape off the brush all the glue that it is possible to get off without allowing the glue to get too cold. When you take the brush out of the pot, work fast; get all the glue possible off the brush and get the rest on the belt at once. Make two or three fast strokes across the belt and close down the splice and rub for dear life. After the first brushful has been applied (and rubbed for about two minutes), have an assistant raise the point up until you can see the glue breaking all across the whole width of the belt. Then have a second brush ready and repeat the former process, with the exception that you need not apply the glue to both sides of the leather as in the first case; for if you will keep the brush down in the fork between the two laps you will give both sides a coat, and in addition to the time saved by using this method you will get the joint closed while the glue is hot. As fast as you go across the belt with the brush, have the assistant roll the belt together after you; when you have used all the glue out of the brush, the joint is closed and ready to rub. You will keep the glue much hotter by immediately closing the splice after the brush, and there is nothing else so important as using hot glue; as soon as it commences to get shiny on the surface the thing is all off and it will not hold anything.
You cannot do any quick work with water in your glue—that is, unless it is old and has been heated up several times. If this is the case, it will have to be thinned with water. The proper consistency is about that of a very heavy grade of cylinder oil; if it is too thin, it will not dry in any reasonable time and it will also cause pockets in the splice by opening up after the joint has been rubbed, and the air in the pockets will open the whole splice. In important work never use a glue that will not stick so tightly between every application belt that after rubbing down you can give it a good, hard pull without its opening up. In all statements regarding the time necessary for the joint to dry, the belts are considered absolutely clean, dry and free from all oils.
The most disagreeable portion of the belt repairer's work is the splicing and repairing of oil-soaked belts. It is a well-known fact that the action of oil and that of glue are in direct opposition to each other: the oil prevents sticking and the glue sticks, if it has a chance. Such being the case, the first thing to do is to eliminate the oil completely, and the efficiency of your joint will be in direct proportion to your success in getting rid of the oil. To this end secure a large gasoline blow torch, such as painters use to burn off old paint. If you are not used to it, be very careful; at all events, have a bucket of dry sand to use in case of trouble. Just throw the sand on the fire and the fire will go out—that is, if you can get the sand in the right place.
The torch is to be used after the splice has been all completed except the thin points. The flame will burn them if finished, so leave them tolerably thick until after the oil has been removed; then finish them as directed before. When the scarfs have been made and the old glue has been removed, turn the flame (which should be an almost invisible blue if the torch is working properly) directly on the leather and move it over all the surface of the splice until the leather has become thoroughly heated; never allow the flame to remain directed at any point long enough to make the oil in the leather boil. If you do, the belt is burned. Continue to move the flame over the surface of the belt until the leather is so hot that the hand can scarcely be held on it. With one of the scrapers shown in Figs. 69 and 69b (69b preferred) scrape the oil off as the heat raises it up. Turn the cutting edge of the scraper up and wipe the oil off after every stroke; keep the scraping process going right on after the torch; never allow the leather to cool off until you can get practically no oil and the leather begins to turn brown. By heating the leather and bringing the oil to the surface you do just what the glue does when you put it on an oil-soaked belt without removing the oil. By means of the heat contained in it, it brings up all the oil near the surface to which it is applied and in consequence does not take any hold on the leather.
It will take two men with all the necessary tools and appliances at least six hours of good hard work to remove the oil from a well-soaked 36-inch belt—that is, to remove it to an extent sufficient to warrant the gluing of it.
In case of overflows in which the wheel pits are liable to be filled with water, pour cylinder oil on all belts that are liable to get wet and then remove them from pulleys if they will be covered for more than twenty-four hours, clean them with gasoline and they will be found to be all right and dry.
Hold a clean piece of waste against all belts at least twice every twenty hours, and wipe them clean.