In making a shoe, whether by hand or machine, the leather must be solidified by hammering or rolling: it must be skit-ed. that is trimmed down to a uniform thickness. and all imperfections eut away; the parts must be cut out and the differ ent portions composing the upper sewed together. The sole consists of two portions: the insole of soft and the outer sole of heavier leather. The insole, rendered pliant by soaking in water, is first tacked to the last. Next its outer edge a channel, called a [collier, is dug about inch deep, along which holes for the stitches are pierced obliquely through the leather into the channel. The top is next lasted, an operation requiring great skill. The welt is then placed around the sole as far as the heel, and then the upper welt and insole are sewed together in one seam. The bottom is then leveled up by filling in the depressed portion formed by the welt with tarred paper or other material. The outer sole, which has first been soaked and then thor oughly hammered on the la pstone, is now tem porarily tacked to the insole. A narrow chan nel is then cut around the edge, through which the sole is securely stitched to the welt. The heel, built of several layers, or lifts, is now nailed to the sole. and the shoe is ready for the final processes of trimming, polishing. etc. Three other methods are employed for fastening the soles to the uppers: pegging, nailing or riveting, and screwing.
Probably the first piece of machinery that was applied to shoemaking was a combined lasting and sole-nailing machine, invented in England by M. J. Brunel, in 1810. In America the first invention which materially changed the methods of the shoemaker was the use of wooden pegs for fastening the soles and uppers together. With their adoption the development of the modern shoe factory began. At first only a small por tion of the work was done in the general fac tory. the rest being performed in private homes, or in shops, as before, hut with this great ditTer ence, that the shoes were to be sold at whole sale, 'ready-made,' and not according to the orders of individual customers. Shoemaking was divided into three parts: 'cutting.' binding,' and 'bottoming.' The cutting was done at the central factory; then the uppers were sent out to one set of workmen, often women and chil dren, to be sewed in their homes; last of all the bottoms and uppers were sent out to local shoe makers, who, in their little S X10 shops, formed what was known as a 'team' of workmen, who put the parts together, one man doing the lasting, another the pegging, and a third the trimming, About 1850 the rolling machine was intro duced, by which the sole leather is thoroughly compressed in a minute, a process which had re quired an hour's time of laborious pounding with hammer and lap-stone. A little later the Howe sewing machine was adapted to the sewing of the leather uppers. About the same time horse power, and soon after steam-power, was applied to the running of shoe-making machinery, and with the adoption of the latter the various branches of shoe-making were gathered together under one roof. In 180 the McKay sewing ma chine, for sewing the uppers and soles together, was introduced, and at once revolutionized the business. See SEWING MACHINE.
An improvement upon this was the Goodyear welt machine, introduced about 1S77, by means of which the uppers and soles are secured by means of a welt, as previously described. In 18s1 the invention of the Reese button-hole machine still further narrowed the sphere of hand-sewing in the manufacture of shoes.
Of the other earlier inventions the more im portant are: The cable screw-wire machine for fastening uppers and ,oles together (1869) ; Bigelow's and McKay's heeling machines (1870) ; and the edge-trimming machine, (1876). During the last two decades of the nineteenth century many other important machines were invented. in cluding polishers and trimmers. From a hun dred to two hundred different pieces of machinery are now commonly employed in a single factory.
The transformation of the raw material into a finished shoe involves over a hundred different manipulations. Boot, and shoes are made in twenty-six different lengths, numbered in two series from 1 to 13. Between most of the num bers half-sizes are made and often five different widths for each half size.
The modern factory usually consists of five de partments or rooms. In the first room the sole leather is first run through a skiving machine, which pares off the leather to a uniform thick ness, rejecting thin and ragged portions. It is then solidified in a rolling machine, after which the soles may lie cut out. This is accomplished either by means of dies operated by a steam hammer or by machine-driven knives, which fol low rapidly around a pattern laid on the leather. The heels are also cut by means of dies and vari ous forms of machinery in use for building them up. The cutting of the uppers, as well as of the soles and linings, is often done by dies or other cutting machinery. But the hest work is still done with a knife, by hand, in order to make sure that the parts are cut the right way of the grain and out of a portion of the skin of uniform text ure. The tips are cut by punching machines with many different dies, according to shape and pat terning. In the stitching room the sawing ma chines are driven by power and often there is a separate girl and machine for each seam. In the bottoming room the tippers are lasted and soled and then heeled.
Different methods of heeling are in practice. By one the lifts are nailed together by a nailing machine, which both cuts the wire off the reel and drives it through the heel. By another, the heel, instead of being built up separately and then secured to the boot, is built up on the boot, and when the top piece is on, the heel is pared am] the front curve or breast formed. The final shaping of the heel usually involves several manipulations. In the fifth room the final operations of trimming and polishing are conducted. The trimming is ef fected by specially adjusted, rapidly revolving wheels. The final polishing is done by machine driven burnishers. sandpaperers, and other pol ishing devices. Last of all, if a shiny surface is desired, the shoe is given a coat of liquid pol ish and rubbed with a hot iron. If a dull finish is desired, as in calfskin, the shoe is rubbed with grease and then with an ebony stick. When the shoes are screwed or riveted, the process is, of course, somewhat changed. In riveted work no welt is used. In screwing, a reel of stout wire is provided with a screw thread, which is driven by the machine through the outer sole, inner sole, and upper and then cut off evenly. This makes a strong, durable shoe. A great variety of different leathers are used in making shoes, including alligator, lizard, snake, and mon key skins, as well as the more common kinds.