A Manual of Shoemaking and Leather and Rubber Products

by William H. Dooley

Sole fastening is performed by a number of operations, in which a score or more of separate machines are used. The sole layers smear a rubber cement over this welt with a “cementing machine,” after the outsole has been soaked in water to make it pliable, and then place it on the shoe and tack a single nail in the heel. The “sole laying machine,” through great pressure, cements the sole on and fits it to every curve of the last. Then the sole is trimmed by a “rough rounding machine,” which trims the soles to the shape of the last. This machine also channels the outer sole at the same time, which is necessary for the next operation. The “channel opening machine” now turns up the lips of the channel and the sole is ready to be stitched to the welt.

The outsole is now sewed by a waxed thread to the welt, by an “outsole lock stitch machine,” which is similar to a welt sewing machine. The stitch is finer and extends from the slit (channel) to the upper side of the welt, where it shows after the shoe has been finished.

It unites the sole and welt with a tightly drawn lock stitch of remarkable strength. It sews through an inch of leather as easily as a woman would sew through a piece of cloth. The stitches are made through the welt and outer sole, the seam running in the channel of the outsole.

Leveling. See [page 135].

Heeling. See [page 136].

The inside of the slit in which this stitch has just been made is now coated with cement by means of a brush. The channel lip is forced back to its original position after the cement has dried, by a rapidly revolving wheel of a “channel laying machine.” In this way the stitches are hidden.

Welt shoes are stitched on in three different ways: “channeled,” which, when finished, leaves an invisible stitch on the bottom of the sole; “regular stitched aloft,” showing the stitches on both sides; and “fudge stitched,” in which the seam is sunk down in a groove, being almost invisible from the welt side.

Every stitch must be of such a nature that it is independent of the one next to it, so that should one stitch break, the others will not work loose. This is accomplished by running the threads through a pan of hot wax just before entering the leather, which causes the waxed thread to solidify, becoming, as it were, a part of the leather.