Show how to cut belts square for better belt service BY F D rim RICH human nature p plays lays an important part in getting service and longer life out of a belt it is human nature to do things in what seems the easiest way not always realizing it is often the most expensive and usually the most laborious because it necessitates doing the work over and over again this applies particularly in the case of cutting belting and joining it cutting the ends of a belt to put it into service seems such a simple thing that often A 1 A belt joined this way cannot run true and evenly the belt man does not give it the consideration necessary to insure the best results and much of the difficulty with otherwise good belts is due to their not bein being g cut and joined accurately when you know how it is as easy to make a belt joint which will run the same as endless as it is to do it by careless rule of thumb methods when a belt runs wobbly or races back and forth across the pulleys it is not 21 giving its best service nor can it have its longest 2 hold the square tightly against the edge until you have cut all the way through the belt life if you have a belt that is repeatedly jurn jumping ping off the pulleys you are paying about twice as much as you should for it because its life is being shortened and you are paying for power that is lost and production that you dont get you are also repeatedly Peat edly paying for unnecessary time and lar bor in fixing things up provided that its ends are cut square and it is joined care a belt can be made to run as straight as an arrow if the pulleys are lined up true dont guess at cutting belt ends dont guess at cutting your belt ends use a square always and use it with care r you do not use a square one or both of the ends will be cut unevenly or irregularly cot bales Eti gincer Crese Ore scent ent belt beit fastener ra stener ciany fourth ave now new york which prevents smooth running 1 even th the e use of a straightedge straight edge does not assure the perfect results obtained by using a square for the slip of a fraction of an inch will bring the belt ends together at an angle as shown in illustration no 1 this results in the belt shimmying on the pulley which is bad for the belt and impairs its service for as it moves from side to side the line of direct pull AB A B moves from one side of the belt to the other imposing shifting and irregular strains which no belt can stand indefinitely there is only one way to assure correct rd results that is to use a belt square and to keep it in place until you have cut all the way through the belt dont just scratch the surface and then hack through cutting to the square assures an even cut all the way through the belt and all the way across it means that the belt ends can be brought together 1 ether in a tight but evenly running flush joint for belts up to fifteen or eighteen inches 3 this simple stunt makes square cutting easy and positive wide you can use the ordinary square press it firmly against the edge of the belt and when cutting hold the knife vertically see illustration no 2 pointers on details of belt cutting be sure your knife is sharp wet the point of your knife occasionally as it cuts more easily when the blade is wet when a number of belts have to be cut a good stunt is to drive two nails in a large block of wood corid and against these set the edge of the belt and the edge of the square as shown in illustration no 3 this prevents either the belt or the square slipping some men tack a slip of leather or a piece of old belt on the end of the block to protect the A A in from the measuring 4 find the center b by edges of the be belc it comes through the point of the knife as belt t to square difficult wide belts are more mor e is often i nereas difficulty correctly and the edby ed by slight variations in width which throws the square out to avoid this and assure perfect results the method described below has proven the best at any point near where you are going to cut the belt measure across and find the center as at AA A A illustration no 4 at any distance back of this two or three feet find the center again as at BB B B between these two center points draw a clean sharp line this marks the center axis of the belt beli now as in illustration no 5 using the CUTT CUTTING 1145 c e el 5 square by working from the center line and you wont go wrong square afaf against in st the center line trim off the end of the belt holding the square firmly in position while you cut all the way through two small nails driven in on the center line will keep the square from slipping for cutting the other end of the belt find the center line the same as just described then at any point on this line other than where your jour belt clamps will come take a point C asin as in illustration no 5 then using the square as illustrated draw a line D C E at right angles to the axis and all the way across from edge to edge it is sometimes easier to draw this line by marking the points D and E and then placing a straightedge straight edge through the points D CE C E to draw the line see illustration no 6 be D C E 6 on wide belts use a straight edge when you a large enough square sure your straightedge straight edge is straight not warped this line D C E will constitute a base line to measure from after the belt is in the clamps do not cut on this line you can determine exactly where you want to cut after the clamps have been put on and the belt brought into position then measure forward from the line DE D E an equal distance on each side of the belt to the cutting point you can use calipers and measure over the belt clamp or run your ruler through the edges of the clamp As a matter of convenience always cut one end of the belt square and get it ready for making the joint before putting the belt into the clamp remember that when you are doing a job it is much easier to do it right th than an to do it over this applies to making the completed joint as well as to cutting the belt therefore it is best when joining a belt to do so in a way which is permanent and which insures the belts most satisfactory service opposes hole punching method personally the writer who has had considerable sid erable experience in working with belting manufacturers in solving the difficult problems of efficient belt joining is very much opposed to methods which punch holes in the belt or which in any way cut or weaken the lengthwise power carrying fibres fabres of the belt any thinking man can see that no belt can give better service than its method of joining will permit and if wasteful or destructive tive means are employed the strength of the belt is lessened its service impaired and its life shortened it is no uncommon thing to see in journeys through manufacturing plants laced belts in which from 40 per cent to frequently more than 70 per cent of the cross section of the belt is removed in punched holes how in the name of common sense can such a belt joint be expected to give the full service of the belt many manufacturers are today running belts much heavier and more expensive than their requirements in an attempt to get strength at the joint there are many types of metal fasteners fastener s in common use which from an engineering standpoint are but slightly if any more satisfactory is than lacing methods for several reasons first because many of them sever the lengthwise power carrying fibres fabres see sec I 1 p ll 11 7 example of punching job as ordinarily done in the rush of work aggregate amount punched out is equal to 75 per cent of cross section ond because others place all the strain in a straight line comparatively close to the end of the belt third because some make a joint which is so stiff and hard that they pound on the pulleys and cause the belt to break back of the joint fourth because many put metal in contact with the pulleys which causes noise and wears and crystallizes the metal so that such joints must be constantly watched both to prevent danger to workmen and failure of the joint the ideal joint is one which would run the same as endless without the drawbacks or difficulty in making and later shortening to take up stretch belting manufacturers themselves estimate that only a very small percentage of belts need to be made actually endless their estimates range from one half to I 1 per cent to 2 per cent as endless requirements quire ments it is possible to make belt joints which run the same as endless and which meet all requirements of this 98 to 99 per cent of the belting field without having any of the objections noted above below is a table showing the qualifications of the perfect belt joint by which any engineer can check up the comparative efficiency fici ency of his own methods the per cent efficient belt joint 1 will maintain maximum strength of belt 2 will avoid destruction or weakening of the lengthwise power carry ing belt fibres fabres 3 should prevent breaking the belt back of the joint 4 must not hammer on the pulleys 5 must not be subject to wear or to crystallization 6 will insure continuous uninterrupted operation without supervision 7 hugs the pulleys tightly and insures full transmission of power 8 runs silent silently lyv same as endless 9 can be easily taken apart for removing or shortening the belt 10 Is safe against accidents or breakdowns 11 must be easily and quickly made without special equipment 12 will last for the life of the belt the leading manufacturers of belt fasteners are always willing to give engineers full data regarding their product and a checkup check up of the different methods a against 6 ainest the above should enable any engineer to determine for himself which is going to assure his gl getting etting the most satisfactory results and service from his belting but regardless of whatever method of joining is used the belt should always be cut square so that it may exert a straight line pull and perform its function of power transmission efficiently |