May i, 1904.] 



THE INDIA RUBBER WORLD 



273 



THE MANUFACTURE OF SHOE LASTS. 



THE coming molded rubber shoe may, in the course of 

 time, render maple lasts superfluous but, until then, in 

 every variety of style, width, and size, they will con- 

 tinue to hold an important place as one of the expen- 

 sive accessories of the rubber shoe industry. The lumbering 

 for maple timber from which shoe lasts are made takes place 

 in the woods of northern Maine and Canada. 



The felling of the trees is done in winter when the sap is 

 down out of the trunks, and the snow covered ground affords 

 good hauling. The trees are very carefully selected, because 

 not all maples are adapted to make good last blocks. The best 

 variety is the rock maple, better known as the sugar maple. 

 The trees are cut for last blocks where it does not pay to con- 

 tinue the manufacture of maple sugar. The habit of the rock 

 maple is to grow in clumps or groves, oftentimes many miles 

 apart, which greatly increases the labor and hardship of lum- 

 bering. It is a strenuous sort of life, fifteen or twenty miles 

 back in the bush, felling trees in the snow, with the tempera- 

 ture 15* below zero. It sometimes happens that unusually 

 heavy snowfalls will cut the camp off from supplies of fodder 

 for the animals and necessitate killing them. 



After felling and trimming, the timber is hauled on runners 

 to central points near camp and there cut, generally by horse 

 power with a drag saw, into block lengths. The bark is re- 

 moved from these sections and they are then marked on the 

 end with the pattern of the block desired. With these outlines 

 as guides, the tree section is carefully split into blocks of the 



general shape shown in Figure I, which represents the side 

 and both end views of a rough block as they are usually cut. 



The work of splitting is carefully done by holding a broad 

 axe on the mark, while it is struck by a blow from a wooden 

 mallet or beetle. When thus roughly split the blocks are 

 packed for seasoning or air drying in open sheds, for nearly two 

 years. Following this long interval of open air drying, comes a 

 period of three months in a warm kiln at the last factory before 

 they are ready for the turning lathe. Indeed, they generally go 

 from the kilns to a drying room of lower temperature, where 

 they are kept in stock and from which they are selected and re- 

 moved as needed for turning. 



The standard irregular turning lathe shown in the illustration 

 is one of the notable inventions of the nineteenth century. It 

 has undergone improvements which make its capabilities still 

 more remarkable today than when first invented. On these 

 machines such irregular forms as shoe lasts, hat blocks, gun 

 stocks, and many other unsymmetrical shapes are turned, not 

 only to the exact dimensions of a given model, but in various 

 gradations of sizes, larger and smaller, or right or left, in which 

 the proportions of the model are perfectly reproduced. The 

 machine is known as an " improved reverse last lathe." It is an 

 American invention, the result of forty years of experience, and 

 in general use for last turning in this and many foreign coun- 

 tries. 



The machine turns both "rights" and "lefts" accurately 



from one model, and grades five sizes both larger and smaller 

 than the model size. The capacity varies from 50 to 100 pairs 

 per ten hours, according to size and fineness of feed. It re- 

 quires about 1 'A horse power to operate it. The speed of the 

 cutters varies from 4500 to 5000 revolutions per minute. 



The principle on which the machine operates is not difficult 

 of comprehension. The model last is centered in one side of a 



swinging frame, 

 and the block to 

 beturned, roughly 

 cut on a circular 

 saw to approxi- 

 mate dimensions, 

 is centered in the 

 other side of the 

 frame, on the same 

 axis. The model 

 rests against a 

 guide wheel and 

 as each revolves 

 the latter also 

 travels, by an ad- 

 justable feed, 

 lengthwise, thus 

 traversing the en- 

 tire area of the 

 model. The 

 block to be 

 turned revolves 



FIO. 2. LAST LATHE. j n un i SO n with 



the model and in contact with the cutting wheel or head. The 

 swing of the frame is determined by the contour of the model 

 and as the latter rises and falls on the face of the guide wheel the 

 block also similarly advances and retreats against the cutting 

 wheel and a duplicate of the model is cut in the block. 



Variations in size or width and in right or left are simply a 

 matter of detail in adjustment. The cutters on the face of the 

 wheel are gouge shaped and several in number and are ad- 

 justed each in advance of the preceding, thus making a pro- 

 gressive cut capable of removing rapidly a considerable depth 

 of wood. Immediately around the cutting wheel is arranged a 



FIQ. 3. COLLECTION OF LASTS. 



