Part 4

In taking down solid pulleys from main or counter shafting it sometimes happens that a hanger must be removed to permit the pulley to be taken off. A first-rate plan is to make a couple of long bolts hooked at the end as shown in Fig 58; pass the hook around the shaft and the threaded end through a hole in the stringer. By screwing up the nut as shown, the shaft and remaining pulleys can be kept in position, obviating the use of tackle, not to mention the labor required to hoist back the shaft into position. The application of this contrivance is especially valuable where heavy cone pulleys are required to be lowered or changed. It will be seen that if we employ a pipe thread we will be enabled to suit almost any condition of length that may arise between the shaft and stringer.

VII

PRACTICAL METHODS OF LOOSENING PULLEYS

WHEN a solid pulley is to be removed from a piece of shaft for any reason, it is not good policy to use sledge hammers on the spokes or hub to do it. Cast iron in pulleys is too liable to break or crack under repeated blows.

In Fig. 59 one ready method is illustrated by which the pulley may be removed. When a place between two walls can be found that will admit of this arrangement, proceed as shown to force the shaft through the pulley, substituting longer pieces of pipe as the shaft is forced through farther.

In one case where a large pulley was stuck on a 7-inch shaft and its removal was imperative, the shaft was sawed off (with large hack-saws) close up to the pulley hub and two 5/8-inch holes were drilled into the shaft parallel to its axis, as shown in Fig. 60. These holes were drilled so that they were 90 degrees apart and came within 1/16-inch of the hub of the pulley. The hub was 14 inches through and these holes were 8 inches deep; but that was enough to loosen up the shaft so that when the pulley was laid over on beams with the shaft hanging through, a sledge hammer applied on the shaft end soon drove it out.

Another way to remove a pulley is shown in Fig. 61, where a ram is used. The ram is another piece of old shaft. To prevent its damaging the pulley hub and also to have its force applied most advantageously, it should be used in a direct line with the direction of removal. To do this, the method shown in Fig. 61 is self-explanatory.

Another good method of removing an obdurate pulley is illustrated in Fig. 62, where the bolts _W_, _W_ must have long threads and the work is done by pulling up on the nuts _A_, _A_. This method can be used only when the end of the shaft can be reached and used as shown. In using this method, care must be exercised in the pulling up on the bolts _W_, _W_, keeping the strain equally divided between the two by pulling a little at a time on each.

If the pulley comes extra hard, it can be assisted when the strain is on the bolts by striking at _X_ with a sledge.

A good device for removing motor and generator pulleys that are near the shaft end is shown in Fig. 63. The arms _Z_, _Z_ are adjustable to take hold of hub or arms, and the screw applied to the shaft center will do the rest.

To run a pulley off a shaft without injury to the hands, use a monkey wrench on the rim of each pulley, as shown in Fig. 64. One pulley on the shaft can be selected for a hold-back; one monkey wrench there will hold the shaft from turning, while the other will turn around the shaft the pulley which it is intended to remove.

VIII

SPLICING LEATHER BELTS[5]

THE first thing is the tools for the different kinds of work. These may be usually changed somewhat to suit the taste of the user, but in the main the style and kind herein shown in attached drawings cannot be very much improved upon.

[5] Contributed to Power by Walter E. Dixon, M. E.

Figs. 65 and 66 show a splice opener for heavy belts. It is made of 1/2-inch tool steel with the point spread out about 2 inches wide and well tempered, after which it is ground to a good sharp edge, and then an oil stone run over the edge until it has been dulled so that it will not cut. The right kind of an edge can only be secured by trying; it is one of the tools that is very hard to get just right. You will notice that the manner in which this splitter is built may seem to be rather too much work to bestow on such a simple tool, but the reasons for so doing are as follows: in opening a 36-inch belt an old splice opener that was driven into the handle like an ordinary file was used and the handle split; that sharp point came back through the handle, and when it finally stopped it had gone about 2 inches into the palm of the operator's hand. Some 1/2-inch hexagon steel was turned down 6 inches, just enough to round it up; then a solid brass washer was turned out 1-1/4 inches in diameter and 1 inch thick, a hole bored through it that was a driving fit on the piece of steel and was driven down to the shoulder. Washers were cut out of old pieces of belt and put on with a liberal coat of glue on both sides; when the handle was filled, a steel washer which was 1/2 inch thick was screwed down hard on the leather washers, and when it had dried well the whole was turned down to size shown in the sketch. Two of these tools were made, one for belts up to 18 inches, and another that will reach through a 40-inch belt. The tool shown in Fig. 67 is an ordinary heavy screwdriver with the point rounded nicely, and it is used to raise the thin points that the larger tool will sometimes tear.

Fig. 68 shows a handle made almost like the one in Fig. 65, with the exception that the brass washer referred to in Fig. 65 is here turned down to 3/4 inch, commencing 1/2 inch from the large end, which is 1 inch in diameter. The leather washers are slipped on over the small part until it is filled, and then a washer is screwed on the small end and the whole turned as shown in the sketch. A hole that will tap out 3/8 inch is bored in the large end of the brass center, and then tools made with threaded ends on them that will fit into it. These tools are made of 3/8-inch tool steel with scraping ends, as shown. These scrapers are used only for removing glue that is too hard and too thick to be removed by the scraper shown in Fig. 69.

Figs. 69, 69a and 69b show views of the only tool that is hardly worth being referred to as a leather-cutting tool. It is made of a thin piece of steel, about 18 gage, or any old hand-saw will make the very best scrapers that can be secured. They should be about 4 inches square, perhaps a little smaller, and fixed in a hardwood handle (usually of hard maple), simply by sawing about 2-1/2 inches into the handle and then driving the blade in. The saw cut should be just a trifle thinner than the piece of steel. Should they get loose from use, a piece of paper folded over the back of the blade and forced back into the handle with the blade will usually tighten it all right.

This is the tool that will ordinarily worry the novice more than all the rest to keep in proper condition. Fig. 70 shows an exaggerated view of how the blade should look when properly finished. It should be hooked considerably.

Fig. 71 shows a small steel for sharpening the scraper after it is turned, and it should be absolutely smooth.

Fig. 72 shows the equipment for turning the edge of the scrapers. A large three-cornered file, about 12 inches long, which has all the teeth ground carefully off of it and then nicely polished, is fastened to a piece of good clean belt leather by means of the staples shown.

Fig. 73 shows the method employed in turning the edge of the scraper, which is as follows: After the blade has been set firmly in the handle, grind the edge rounding, as is shown in Fig. 69; then grind sharp with a good long taper of about 3/8, and grind from both sides just as you would an ordinary axe. After you have a good smooth edge on it, put it on an oil or water stone and put as fine an edge as possible on it, then put on a smooth piece of leather and hone it down until it would shave you. You will then have a tool that will do a world of work for you, "if you will turn it right." The method shown in Fig. 73, if properly carried out, will do the trick for you; the thing to be remembered is that at no time in the turning of the scraper must the cutting edge bear on the smooth file. The first position is not shown right; the handle should be allowed to touch the file the first few times it is passed over, and then gradually raise the handle and keep on passing the blade from side to side, as is shown in Fig. 74; allowing it to slip off on the leather every time you cross the file; this is to keep the corners in proper shape. Another thing to remember is to bear down on the blade as it is passed over the file; you can't bear too hard; the only thing to look out for is not to raise the handle too fast. An ordinary blade can be turned in about fifty strokes across the file. The edge turned over should be at least 1/16 inch long and should be well hooked, as is shown in Fig. 73.

It is well to keep on hand about six of these scrapers, and as they get too dull to cut leather use them on glue. With one good scraper that is not too sharp all the glue can be cleaned off of both points of a 36-inch belt in from five to ten minutes. When the edge gets a trifle dull, use the small steel on both sides of the edge; first wet the steel with the lips, it makes a much better edge. For the benefit of beginners who may attempt to splice a belt for the first time, do not use a glue that will not allow you to remove the clamps and put on the full load in forty-five minutes after the glue has been applied and well rubbed down. The time given here applies only to clean belts that are absolutely free from all oils, and does not include old oil-soaked leather that no glue will ever dry on.

Fig. 75 shows the equipment necessary to do a good, quick job on a belt, and most of them are required to be done quickly and well. With such an outfit and half-dozen sharp scrapers a joint in a 36-inch belt can be made and run again in four hours after the engine is stopped. This includes all the time consumed in putting on and taking off the clamps, etc.

The top of the platform, 76d, is level with the bottom of the belt and is held in position by the hooks, 76b, which are shown in Figs. 75 and 76. These hooks slip over the 2×4-inch pieces that project outside the platform to which they are attached, and should be made of three-quarter iron and not too long, or some difficulty may be experienced in getting them on the two-by-fours.

The rods should be long enough to take care of the longest possible splice and still give plenty of room to work. There should be about 2-1/2 feet between the inside ends of the threads and the threaded end should be 3 feet long. This will make the rod 8 feet 6 inches long, and it will be none too long at that. For instance, in removing the glue from the splice, if the last end point is very close to the clamp, there will be great difficulty in cleaning it and also in fitting the leather after the belt has been shortened. What is meant by the head end splice is the one that is on the pulley first--the arrows in Figs. 77 and 78 will make this clear: they indicate the direction in which the belt should run; therefore that end of the piece of leather that is on the pulley first is the head end (or first end) and the end that leaves the pulley last is the last end. If the two belts shown in the sketch were reversed, the points would be turned up by everything that touched them; whereas, running in the direction that they do, everything that touches them has a tendency to rub them down.

We will suppose that the belt shown in Fig. 75 had a "first end" point that opened on the top of the belt instead of the bottom as this one does (see left-hand end of belt between the clamps, on the lower side); one can easily see how hard it would be to work if the clamp were near the point. There should always be enough room between the clamps to allow the splicer to take the last end (which is always the forked end), carry it entirely over the clamp toward the left in Fig. 75, lay it down on that part of the belt that is outside the clamp and slip an extra splicing board under it. Fasten the two belts and splicing board all together by means of a couple of 8-inch hand-screws (of which every belt splicer should have at least six or eight); then clean and shape it to suit the other end. It can be passed back over the clamp from time to time and tried for a fit.

The proper mode of procedure in splicing a belt on the pulleys is as follows: Decide on where the belt is to be opened, and always open it in the worst place in the belt for that is the place you certainly want to fix. Pay no attention whatever to any former splicing place that may be in the belt, but take it apart at any place where you are sure repairs are actually necessary. First put in the most convenient place possible the point that you have decided to open and then put the clamps in position. If you are sure that it is going to require very hard pulling to get it as tight as you wish, take a damp cloth, moisten the inside of the clamps and then sprinkle powdered resin on both upper and lower clamp. Put the "first end" clamp on first, as this is always the easiest point to clean and fit; decide how much you will have to take out, or as near as possible, measure off this amount on the belt and place the clamp this distance plus about 10 inches from the "first end" point. This extra 10 inches will give you plenty of room to clean the glue off and also to shorten up the belt the right amount, for all the shortening must be done on the "first end" point on account of the ease with which the new scarf can be made.

Should you try to shorten up from the "last end" point, by referring to Fig. 78, you can easily see the amount of work you would be in for. There would be two thin ends to scarf, and outside ends at that; whereas if you shorten up from the "first end" you make only one thin end and that one in the inside of the belt.

The first clamp, with the center mark of the clamp coinciding with the center of the belt, should be very tight; for should it slip when the load is put on, it will very probably slip in the middle of the belt and may not slip on the edges at all. Should you glue it in this condition, the chances are very much in favor of the outside edges giving away on a heavy load, due to the middle being too long. After the first clamp is in position and tightened, put on the second one and leave the bolts loose, so that it can be slipped easily. Then put the belt rods in position with just a "full nut" on each end and tighten the clamp. Tighten the rods enough to take most of the load, then get the large splitter shown in Figs. 65 and 66 and open the joint. The place to commence is between _X X_ in Fig. 75; this inclined point is about 4 inches long and must be opened at both ends of the splice before the middle is touched.

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 × 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 × 6 × 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.